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PAL Questions: 829 - Garden Tools: 346 - Recommended Websites: 680

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Keywords: Vitis

PAL Question:

Do you have any information on a new grape variety called Sweet Seduction? I am interested in vigor, fruit set, and ripening time.

View Answer:

Depending on the source, this is either a beautiful and productive grape or a straggly one with poorly filled clusters. It received praise from Lon Rombough, a grape expert from Oregon. The Home Orchard Society has a brief discussion about Sweet Seduction. These first two sources do not think much of this seedless grape. It is also mentioned in a list of American grapes and hybrids in the book McGee and Stuckey's Bountiful Container (Workman, 2002):
"Introduced by Oregon grape grower Bill Schulz, Sweet Seduction is an unusual variety with exceptional flavor. It produces beautiful golden yellow seedless grapes with a muscat-like taste that we usually associate with European grapes (...) Vigorous and productive, [it] bears large and attractive clusters of its seductively flavored fruit."

Anecdotal comments on the web suggest that this variety begins to bear fruit at between 2 to 3 years after planting, and may produce 10 to 15 pounds of grapes. It is hardy in Sunset zones 5 - 9 and can grow 15 to 20 feet.

Season All Season
Date 2006-03-04
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Keywords: Luzula

PAL Question:

I am looking for information on Luzula purpureosplendens, and all I can find is very general information on the genus Luzula.

View Answer:

Luzula purpureosplendens is endemic to Azores islands, which may be why there is so little information about the species. Another reason it may be hard to find information is that it has synonymous names, according to GlobalSpecies.org, and these are Luzula azorica and Luzula purpurea. If you search either of the synonyms on the web, you will get some results, many quite technical (chromosomal studies).

Season All Season
Date 2008-01-03
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Keywords: Oplopanax horridus, Perennials--Care and maintenance, Native plants--Care and maintenance

PAL Question:

My question is about Oplopanax horridus. I planted one last winter in deep shade. It has lost its leaves and appears to have gone dormant. 1) Does devil's club go dormant in the winter? 2) If not, then could it come back with watering in the winter climate or am I better to rip it out and put in another one? 3) How frequently should devil's club be watered in a normal summer and assuming good loam soil?

View Answer:

Devil's club does lose its leaves in the winter. Quoting from the source cited below, it is hardy down to at least 5 degrees F, although the young growth is likely to be cut back by spring frosts...On cool moist soils, it forms tall, impenetrable thickets...Plant in sun or part-shade.
(Source: The New Royal Horticulture Society Dictionary of Gardening, Vol.3, 1992, p. 378)

Additionally, devil's club "grows in well-drained to poorly drained soils with sandy, silty, or loamy textures," which indicates that it will appreciate regular watering that ensures moist soil in the summer.
(Source: Propagation of Pacific Northwest Native Plants, R. Rose, et al, 1998, p. 129)

Season Winter
Date 2006-03-20
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Keywords: Acer palmatum dissectum, Deer

PAL Question:

Is the Japanese 'Crimson Queen' laceleaf maple deer resistant?

View Answer:

I found Japanese maple (Acer palmatum) on a few lists of deer resistant plants. (One source is Pacific Horticulture, v. 47 (3) 1986, "Co-Existing with Deer," by Mary Lynn Cox)

None of the lists mention specific cultivars, such as your 'Crimson Queen.' But the risk of damage should be lower than other plants that deer prefer. Every article I read warned that a starving deer will eat anything, so no plant is 100% safe.

Season All Season
Date 2006-03-03
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Keywords: Packing for shipment

PAL Question:

What do I have to do to ship a plant via the United States Postal Service? How do I prepare a plant for mailing? I want to mail a one gallon plant.

View Answer:

When sending your one gallon plant, you should mark the box Fragile and Living Plant Material. You should also use the fastest shipping method you can afford, to make sure the plant reaches its destination in good condition. You might also phone your local post office to learn whether there are any other regulations concerning mailing live plants. The U.S. Postal Service provides these basic guidelines for packaging perishable plant matter. Another matter to consider is whether plant quarantine regulations apply to the plant you are shipping, and whether or not you need a permit.

FedEx has a guide has a guide entitled Packaging Guidelines for Flowers and Plants which should help you.

In terms of packing the plant, you should also ensure that the plant does not move around in its box during transport. Avent (see the source below) recommends securing the pot to the side of the box, with strapping or similar material. You may also want to protect the vegetation with breathable material--perhaps biodegradable starch-based packing peanuts?

Source: So You Want to Start a Nursery, T. Avent, 2003, pp. 75-78

Season All Season
Date 2008-01-03
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Keywords: Plant reproduction, Solanum melongena, Quirky

PAL Question:

I read on a cooking blog that it's important to be able to distinguish between male and female eggplants, because males are less seedy and therefore less bitter. Supposedly, the difference can be detected by looking at the indentation at the bottom of the vegetable. Females have long, deep, dash-shaped dents, and males have round, shallow ones. This is the first time I've ever heard of such a thing, and I'm wondering if you can confirm it.

View Answer:

There is no sex difference among eggplant fruits. The confusion may have come from the fact that eggplant flowers have male and female parts. Mary Keith, a nutrition educator with University of Florida Extension says:
"Please, don't waste any sleep over trying to remember which one is which. There are not 'male' or 'female' eggplants. They all come from the female organs of the flower, but eggplant flowers have both male and female organs. The seeds they contain will grow into plants that make flowers with both male and female parts.[...] The shape of the scar where the flower fell off doesnít tell you whether the fruit is a boy or a girl."
Keith goes on to explain the best way to select an eggplant for cooking purposes:
"The best place to start is what you can see, the skin. There should be a little bit of the stem still attached to one end. A ripe eggplant will have a smooth, bright, shiny skin. It should be firm, not hard but not soft and soggy either. Whether it is purple, green, white or striped, if the skin is dull the fruit has been picked for too long. When you press on the skin it should spring right back at you. If it's too hard to press in, then the fruit is too green and underripe. If it goes in and stays in, the fruit is too old. The texture is getting soft and it is more likely to be bitter. In general the smaller ones are usually better. Probably the best way to decide which ones to buy is to weigh them. [...] The heavier one will be the better one. Some people say they can tell by knocking on an eggplant as they do a watermelon. In this case though, you do not want to buy one that sounds hollow. These will be dry and punky inside."

Similar information comes from University of Illinois Extension:
"There is long-standing controversy about male and female eggplants, which is an inaccurate approach considering the fact that fruits are the product of sex and do not have it. However, it is folk wisdom worth some attention. Eggplants have a dimple at the blossom end. The dimple can be very round or oval in shape. The round ones seem to have more seeds and tend to be less meaty, so select the oval dimpled eggplant."

Season All Season
Date 2011-10-28
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Keywords: Vines--Care and maintenance, Hydrangea

PAL Question:

I have had a climbing hydrangea for 4 years - but it has never bloomed. It is growing but does not produce any buds. It gets full sun and is in good soil. What can I do so it will produce blossoms?

View Answer:

I looked in a few books (including Trees and Shrubs for Pacific Northwest Gardens, 1990, by Grant and Grant) about climbing Hydrangea (Hydrangea anomala ssp. petiolaris) and they all said this vine is wonderful and robust but very slow to establish. You may just have to wait a few more years.

This hydrangea prefers a cool, moist root run so be sure to irrigate it in the summer and place a good mulch (such as compost or wood chips) a few inches deep. The mulch should not touch the trunk of the vine at the top of the soil around the vine. Established trees and shrubs don't generally need feeding. Avoid using a fertilizer that is high in nitrogen, or it may add lush, green growth at the expense of flowers.

Here is additional information, from Virginia Cooperative Extension:
Excerpts: "Climbing hydrangeas only bloom on vertical stems Ė vines growing on the ground will not bloom. Minimal pruning is required. They bear lacecap inflorescences with an outer ring of showy white sterile florets around creamy to yellow fertile flowers in late spring. Deadheading can be done right after flowering to save energy and for aesthetics by cutting the inflorescences off above the first leaf. Branches that extend out far from the climbing surface may also be pruned back in summer after flowering to prevent the plants from being pulled from their structures by heavy winds, ice or snow."
Reasons for lack of flowers on various species of Hydrangea:

  • Improper shearing and renewal pruning on H. macrophylla and serrata cultivars
  • Frost injury to early expanding growth buds
  • Pruning more than a month after bloom time in summer
  • Excessive shade
  • Excess nitrogen fertilization

Season All Season
Date 2008-01-03
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Keywords: Vegetative propagation, Gunnera

PAL Question:

When and how do I divide my Gunnera?

View Answer:

"Divide large types before growth starts into single crowns in midspring." (Source: American Horticultural Society Plant Propagation, ed. by A. Toogood, 1999, p. 198)

"Many gunneras are huge and so are impossible to dig up and divide in the conventional sense. For propagation, cut pieces from the edge of the clump. Pot up in a large pot and in a fibrous medium and keep moist." (Source: The Complete Book of Plant Propagation, ed. by C. Heuser, 1997, p. 40)

The sources I looked at indicate that you should divide your Gunnera in April or May. Because of the size of the plant, it may be impractical to divide the rootball. You can use a spade or pitchfork to cut sections from the main clump, and then plant those divisions in pots, keeping them moist. Gunnera is a tough plant, and should take well to this kind of division, as long as there is adequate moisture.

Should you need to protect your Gunnera over the winter months, you can cut the leaves and use them like a tent to protect the crown of the plant during the coldest months.

Season Spring
Date 2006-03-03
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Keywords: Land treatment of wastewater, Landscaping drain fields, Ground cover plants, Grasses, Drought-tolerant plants

PAL Question:

I am looking for plants suitable for a septic drain field site. I have a very large north facing slope in open sun with a drain field running along the top half. I would like to plant low to no maintenance ground covers and low growing shrubs to cover this area. This is a focal point when driving up to my house so I want it to be eye catching and interesting year round.

I thought of heaths and heathers as a possibility, but I'm not sure if the root system is shallow enough. I also would like to include native ground covers such as ferns, Gaultheria shallon and any others that you might think would work, as well as ornamental grasses and perennial flowers for interest. Can you please offer a resource for planting over drain fields or a list of plants that you think would work?

View Answer:

Trees or large shrubs should be kept at least 30 feet away from your drain field. If you do plan to plant trees near a drain field, consult an expert to discuss your ideas and needs. Trees and shrubs generally have extensive root systems that seek out and grow into wet areas like drain fields. Grass is the ideal cover for drain fields. Grasses can be ornamental, mowed in a traditional lawn, or left as an unmowed meadow. You can also try groundcovers and ferns.

The key to planting over the drain field is to select shallow-rooted, low-maintenance, low-water-use plants. When tank covers are buried, keep in mind that plantings over the tank--from inlet to outlet--will have to be removed every three or four years for inspection and pumping.

Planting your drain field will be much different from other experiences you may have had landscaping. First, it is unwise to work the soil, which means no rototilling. Parts of the system may be only six inches under the surface. Adding 2 to 3 inches of topsoil should be fine, but more could be a problem. Second, the plants need to be relatively low-maintenance and low-water use. You will be best off if you select plants for your drain field that, once established, will not require routine watering.

SOURCE: WSU Cooperative Extension - Clallam County

Information can be found here.

Thurston County, Washington, has some information about landscaping a drain field, including plant suggestions, here.

Additionally, the Pacific Northwest Gardener's Book of Lists (1997, by R. & J. McNeilan) offers a number of groundcover lists for various situations, including groundcovers for dry sites, slopes, and sun and shade. The Miller Library has this book.

Season All Season
Date 2008-01-03
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Keywords: Prunus padus, Styrax, Laburnum, Davidia, Ornamental conifers, Ribes, Larix, Chamaecyparis, Picea, Tsuga, Cedrus, Fagus, Betula, Flowering trees, Pinus, Ericaceae (Heath family)

PAL Question:

Are there any lists of shrubs/small trees that are best viewed from below, such as Styrax or Halesia?

View Answer:

While there are no lists of shrubs/small trees best viewed from below, there is a list of trees with weeping habits in The Pacific Northwest Gardener's Book of Lists (Ray and Jan McNeilan, 1997). Many genera of conifers - Cedrus (cedar), Chamaecyparis (cypress), Larix (larch), Picea (spruce), Pinus (pine), and Tsuga (hemlock) - have weeping forms, often indicated by a variety name 'Pendula' or 'Pendulum'. There are weeping birches (Betula), beeches (Fagus), and cherries (Prunus), too.

You are correct about Styrax and Halesia. Additionally, I ran across a few individual species that may be of interest to you as I researched this question:
--Davidia involucrata
--Laburnum anagyroides
--flowering currants, Ribes spp.
--flowering cherry trees, particularly Prunus padus
--various plants in the Ericaceae family have bell-shaped flowers that hang on the underside of the stem.

I would add that any tree which has a naturally graceful branching pattern and/or delicately shaped foliage (such as Japanese maples) would be pleasant to view from below, as well as from other angles.

Season All Season
Date 2007-05-21
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Keywords: Hardy plants, Osmanthus

PAL Question:

Is Osmanthus fragrans hardy enough to withstand winter in Bellevue, WA?

View Answer:

Osmanthus fragrans is a borderline hardy shrub in our area. References vary in the hardiness they quote from zone 7 to zone 9 (Bellevue is zone 8). According to a gardener here at the Center for Urban Horticulture, "it takes a special spot for it to grow and thrive here in the Puget Sound area. The places where I've seen decent specimens and blooms are plants growing up against a warm wall or enclosed somehow by other plantings, buildings, or areas near pavement." If you have a very sheltered spot, for example a courtyard where you could grow it against a south-facing wall, it might be worth a try. Otherwise it seems to be very risky.

Season Winter
Date 2006-03-03
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Keywords: Perennials--Care and maintenance, Pruning

PAL Question:

What causes my chrysanthemums to do the big flop? One even came out of the ground! We have had a lot of rain lately, and it seems like a lot of plants did the big floppy, from roses to sedum, and now the mums. Is it all weather-related?

View Answer:

Yes, certainly the weather contributes to the big flop. Certain perennials just can't stand up to heavy mist and rain.

Some gardeners stake their flop-prone plants before they flop over, while others dig them up and grow things that don't flop.

You can prune perennials to help prevent flop. Typically you cut a perennial back by 1/3 a few months before it flowers. This causes the plant to branch out, producing a bushier, shorter, less floppy plant. In The Well-Tended Perennial Garden (Tracy DiSabato-Aust, 1998), the author suggests that staking be done early: ...after the first flush of growth but before full growth. The stems need to be sturdy, and flower buds should not be formed yet...[stake] without adulterating the normal habit of the plants. Follow the natural line of the stem. (p.63)

Season Winter
Date 2006-03-03
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Keywords: Insect pests--Identification, Pseudotsuga menziesii, Master gardeners

PAL Question:

I have some large second growth Douglas firs in my yard that were topped about 20 years ago. The last several years, almost all of them have developed pitch oozing down their sides from up high. What might be wrong with my trees, and what do you think I should do now?

View Answer:

Disease and pest diagnosis is impossible without actually examining the affected plant. However, based on the symptom of oozing pitch you described, these Pseudotsuga menziesii (Douglas fir) could be suffering from one (or more) of the following pests:

Fir Beetle

Pitch Moth

Twig Weevil

For a proper diagnosis you could hire an arborist. The Pacific Northwest Chapter of the International Society for Arboriculture has a directory of certified arborists.

You could also take many photos and a plant sample to a Master Gardener clinic. This is a free service run by volunteers trained by WSU faculty. Clinic locations and times can be found at this link.

Season All Season
Date 2008-01-03
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Keywords: Plant growth inhibiting substances, Ligustrum

PAL Question:

I have a Japanese privet that has turned into a 30-40 foot tree next to my patio. How can I get it to stop blooming and dropping its flower and seeds onto my patio? Is there a hormone or something that I can use to regulate plant growth, similar to what is given to olive trees to stop them from producing?

View Answer:

There is a product called Florel which is an organophosphate pesticide that has been used to regulate plant growth. The active ingredient is Ethephon which has some health concerns, as described by the Environmental Protection Agency.

Florel was described as an alternative to the toxic chemical, NAA (Naphthalene acetic acid) which has traditionally been used to thin fruit, in an article in Arboriculture, by Harris, Clark and Matheny, 2004, p. 403). However, Florel is still a toxic product and overuse can damage your plants.

Another (non-toxic!) option would be to remove the privet and plant something which will not interfere with your enjoyment of the patio.

Season All Season
Date 2008-01-03
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Keywords: Continuing education, Master gardeners

PAL Question:

I would like to find a speaker for our garden club which meets at the Phinney Neighborhood Center in northwest Seattle. We are a small general interest club. Do you have any suggestions for resources for finding people willing to talk to our club, on topics such as winter interest in the garden?

View Answer:

Here is a link to the King County Master Gardener Volunteers who speak to groups.

Season All Season
Date 2008-01-03
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Keywords: Lawns--Planting, Turfgrasses

PAL Question:

I want to put in a wee bit of lawn, an area of 240 square feet. I have two questions: 1) what seed would you recommend for an area that is mostly dappled shade? 2) how do I prepare the area correctly?

View Answer:

Below is information from the Master Gardeners handbook on home lawns which discusses grass seed for Western Washington gardens on page 6.

What Grass Seed Grows Well in Western Washington?

To establish a lawn in western Washington, choose a combination of turftype tall fescue grasses and turftype perennial rye grasses. A mix that adds up to about 90% of these two grass seed types will grow well in either sun or light shade in western Washington. Turftype perennial ryegrass takes full sun and stands up to traffic. Turftype tall fescues are adapted to shadier locations. In combination, the mix works for a lawn in average light conditions. Mixes containing fine-leaved fescues or chewings fescues will also establish well. Fine-leaved fescues offer bright green color, and will take some shade, but do not take heavy use.

Many commonly-grown grass types from other areas of the United States will not thrive in western Washington's cool, dry summer climate. AVOID mixes with high concentrations of Kentucky blue grasses. DO NOT PLANT Zoysia, bermuda, dichondra, centipede, carpetgrass, St. Augustine, or mondograss. Buffalograss isn't suitable for western Washington, though it may thrive in eastern Washington.

The same document linked above discusses soil and site preparation (pages 2-3):

Soil Conditions for Planting a New Lawn:
Establishing a new lawn successfully depends more on the preparation of the ground before planting than on whether the lawn choice is seed or sod. Lawn failures are often caused by poor soil conditions under the roots. Many times soil surface left for planting after new construction is infertile subsoils, with rocks, lumps, and building detritus left in it. The texture may vary from sands and gravels to heavy, poorly drained clay areas. The best soil texture for a lawn is a sandy loam, containing 60%-70% sand and 30%-40% combined silt and clay.

If the soil isn't well-drained, do not try to amend a heavy clay by dumping sand into it. Adding sand doesn't work, nor does adding gypsum. Amend the soil with organic material, which will help in creating better structure. Use compost, manure, aged sawdust, ground bark, or other organic (previously living) materials. Spread 2 inches on top of the ground and work it in thoroughly 6 to 8 inches down. Getting it completely incorporated is important, because spots of organic material in clumps may decompose and cause a low spot in the finished lawn. Rake away clods and remove large rocks and litter.

Season All Season
Date 2008-01-03
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Keywords: Multipurpose shrubs, Garden design, Perennials

PAL Question:

I have an asymmetrical flower bed in front of my house. It faces southeast and the house is white, with reflection of light. I purchase plants for full sun but they tend to get fried. I am interested in finding perennials to provide interest 12 months of the year. I prefer shrubs with a variety of texture. Plants that attract butterflies would be nice, and any grasses that are known not to grow out of control. What plants do you recommend that would give me a lush, year-round garden?

View Answer:

You may want to plant a mixture of perennials and shrubs, particularly those which tolerate bright light. An excellent book full of lists of plants is Ray and Jan McNeilanís Pacific Northwest Gardenerís Book of Lists (1997). This book includes lists such as Shrubs for Interest in Each Season (pp.62-64), and Herbaceous Perennials for Full Sun All Day (pp.138-139).

I think you may find many of the other lists in this book valuable as you design your flower beds.

The Great Plant Picks website has lists of many different plants that do well in Northwest gardens, including pictures and descriptions.

There are quite a few books which address the issue of providing year-round color and interest in the garden, such as Adrian Bloom's Year-Round Garden: Colour in Your Garden from January to December (Timber Press, 1998) and his Bloom's Best Perennials and Grasses : Expert Plant Choices and Dramatic Combinations for Year-Round Gardens (Timber Press, 2010). The Miller Library also has booklists on topics like Winter Gardening and Perennials which may be of use to you.

And, here is an article entitled "Create a Butterfly Garden" (S. Lamb et al., January 2002) from Oregon State University.

Visiting local gardens throughout the year and noting the plants that appear to be thriving may help, and a trip to your local nursery can give you lots of ideas and information. The Center for Urban Horticulture and the Washington Park Arboretum both feature seasonal plant highlights.

Season All Season
Date 2008-01-03
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Keywords: Ocimum, Mentha, Cooking

PAL Question:

I'm writing an article for a travel magazine about locally grown culinary herbs which are used by chefs in our area. I found a reference to something called "cinnamon mint," but there doesn't seem to be any information available about this plant. In fact, I'm not sure the name is accurate. If it's not an actual mint, are there other mint varieties used in cooking?

View Answer:

I am going on a hunch, having found nothing that suggests there is a species of mint which is called cinnamon mint, that the plant in question is actually cinnamon basil. This is commonly used in cooking. I looked in Mints: A Family of Herbs and Ornamentals by Barbara Perry Lawton (Timber Press, 2002) and noticed cinnamon basil in the index. This plant's botanical name is Ocimum basilicum 'Cinnamon,' and it is described in the chapter entitled "Herbal Mints" (as opposed the what the author calls "true mints") as follows:
"Vigorous plant with a strong flavor of cinnamon combined with the typical basil taste. Terminal spikes of purple flowers rise above glossy green foliage."

Utah State University Cooperative Extension has a publication about mint which mentions several types for culinary use.

Season All Season
Date 2010-06-11
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Keywords: Plant sales, Garden tours

PAL Question:

How can I find out about local plant sales and garden tours?

View Answer:

This page on the Miller Library's website provides information about plant sales and garden tours.

Season All Season
Date 2008-01-03
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Keywords: Mulching, Compost

PAL Question:

Can you give me some good sources for information about mulching and different mulching materials?

View Answer:

Below are many links to information about mulch, including several from Pacific Northwest government agencies. Explore these sites for lots of other useful information about gardening! There are also many helpful books on the subject, such as Mulch It! by Stu Campbell (Storey Books, 2001) and the Brooklyn Botanic Garden's guide, Healthy Soils for Sustainable Gardens edited by Niall Dunne (2009).

Brooklyn Botanic Garden has an excellent introductory article by Janet Marinelli entitled "The Dirt on Mulch", published in Plants & Gardens News, Volume 22, Number 2, Summer 2007.

ABOUT MULCH, types, and uses--Cornell Cooperative Extension (NY)

King County (Washington) Solid Waste Division mulch info
Make the mulch of it!

INFORMATION FROM THE PACIFIC NORTHWEST (generally useful)
-- Saving Water Partnership (Seattle)
--King Conservation District (Washington), manure share program

COMPOSTING COUNCIL OF CANADA:
Compost.org

MULCHING TREES AND SHRUBS
--North Carolina State University:
Mulching Trees and Shrubs

Season All Season
Date 2008-01-03
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Keywords: Symphytum officinale, Weed control

PAL Question:

Comfrey root has taken over my acreage at my home. I want to know how it spreads, how to kill it, naturally and chemically, by the root. I am currently using Roundup sporadically. I don't know how it got into my yard or anything. I would like to be able to kill it off and plant nice grass there in the spring.

View Answer:

Comfrey (Symphytum officinale) has a fibrous root system which is very deep and difficult to eradicate. Any bits of root left in the soil can produce new plants. While it may be tempting to take the quick path and use RoundUp to get rid of your comfrey, you may want to consider the health and environmental consequences of this product, whose active ingredient is glyphosate. Northwest Coalition for Alternatives to Pesticides has information about this chemical.

If you avoid using herbicide, you may find additional uses in the garden for the comfrey you remove by hand. Do not rototill this plant, and always wear gloves when handling it. Dig carefully and remove as much as you can of the roots, and then dispose of them. Pacific Northwest gardener and author Mary Preus writes about comfrey in The Northwest Herb Loverís Handbook (Sasquatch Books, 2000):

Comfrey can play an important role in compost making, The considerable leaf mass of a mature comfrey plant, cut several times in a season, can add plenty of high-nitrogen green material to the pile. In addition, the leaves contain calcium, phosphorus, potassium, and trace minerals drawn deep from the subsoil. Just be sure there are no ripe seeds, and that no pieces of root are attached to the base of the leaves that go into the compost pile.

The leaves can also be added to potato crops as a fertilizer. After allowing them to wilt, you can use the leaves by chopping them up and placing them in a trench with main crop potatoes. As the leaves are high in potassium, they make an excellent fertilizer. Layer to a depth of 1 to 2 inches. Comfrey can also be used on other plants that benefit from high doses of potassium, like tomatoes and runner beans. It has also been used to as a top dressing around soft fruit bushes. As the leaves break down, gently cultivate them into the planting area. For more information see the British NorthWest Dahlia Societyís page about using comfrey. There is also an excellent article from Organic Gardening Magazine by Jean Nick, entitled Comfrey Power, available from the online archive.

If you have large swathes of your garden which are weedy, you can also try sheet mulch as a solution. StopWaste.org has information on how to do this. To simplify, the technique is to spread out a layer of cardboard or newspaper (at 4-6 sheets thick) and cover it with a layer of organic mulch (compost, straw, alfalfa hay--available at feed stores, woodchips, coffee grounds, etc.). Then wait 6-8 months. This is not an exact science because there are many variables, such as thickness of newspaper, type of mulch and what type of plant you're trying to kill. Perennial weeds and especially coarse grass will push through the cardboard once it starts to break down so it is critical that if and when this happens you pull the mulch back and put down more newspaper/cardboard, and then replace the mulch.

Season All Season
Date 2008-01-03
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Keywords: Phormium

PAL Question:

What is the maintenance routine for Phormium?

View Answer:

According to Sunset Western Garden Book (2007), require well-drained soil, and may be prone to crown rot if the site is poorly drained. They are susceptible to damage from cold (below 20 degrees Fahrenheit). The Plant Care Manual by Stefan Buczacki (Crown, 1993) suggests that you provide them with full sun and shelter from cold winds, especially if your plants are variegated cultivars, which are less hardy. Mulch in spring and fall, and provide a balanced fertilizer mid-spring and midsummer. In fall, wear heavy gloves and cut or pull away dead foliage. You may need to divide every 5-6 years.

Season All Season
Date 2008-01-03
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Keywords: Arctostaphylos, Native plant gardening, Mulching

PAL Question:

Is is good to mulch Arctostaphylos uva-ursi? If so, would an aged bark be best or a mulch that contains manure? How deep should the mulch be?

View Answer:

Native Plants in the Coastal Garden (by April Pettinger, 2002, p. 27), says the following about mulching Pacific Northwest native plants:
"...When an established native plant garden requires maintenance, it is usually minimal: mulching is probably the most important---and often the only---maintenance required. In any garden, mulching is arguably the most beneficial care you can give your soil and your plants. There are many advantages to using mulch. It suppresses weeds, conserves moisture by minimizing evaporation, and releases nutrients to the soil...Good mulch materials are compost, decaying leaves, well-rotted manures, sea kelp, mushroom compost, seedless hay or straw, shredded prunings, natural wood chips, grass clippings and evergreen needles and cones. Commercially available screened bark---usually referred to as bark mulch---has little to offer other than its ability to conserve water; it has no nutritional value and in fact depletes the nitrogen in the soil. When spreading mulch, don't pile it too close to stems of plants. If you are using compost as mulch, spread it about 2 to 4 inches deep. Other materials may be applied to a depth of 3 to 7 inches..."

Season All Season
Date 2006-03-20
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Keywords: Insect pests--Control, Arctostaphylos, Aphids

PAL Question:

My Arctostaphylos uva-ursi has suffered from galls caused by aphids. What approach would be best to combat the aphids and when is the best time in their life cycle to attack?

View Answer:

Kinnikinnick or Arctostaphylos uva-ursi sometimes suffers from galls caused by aphids, and is also susceptible to fungal diseases. If your plant has galls, you would see distorted, thickened, and often reddish leaves which almost don't seem leaf-like. The aphids may also secrete honeydew which can then turn blackish with mold.

Douglas Justice, University of British Columbia Botanical Garden Associate Director offers these comments on Arctostaphylos uva-ursi:

The Arctostaphylos uva-ursi cultivar 'Vancouver Jade' -- a UBC introduction and one of the most widely grown cultivars in temperate climates -- is adapted to wetter conditions than many other cultivars, as it was selected from the Pacific Northwest. Nevertheless, like all kinnikinnicks, it is not a plant for poorly drained, shaded or high traffic areas. And unfortunately, it appears to be rather more susceptible to manzanita pod gall aphid than other cultivars. Populations of that insect pest can build up during "warm winter" periods (such as we've been experiencing in Vancouver over the past several years) and disfigure plants significantly.
Source: UBC Botanical Garden Forums

Oregon State University has information about leaf gall on Arctostaphylos uva-ursi in their Plant Disease management handbook online.

The following, from Pacific Northwest Insect Management Handbook (WSU, OSU and U. of Idaho, 2005) provides more information about the aphids.

Kinnikinnick Arctostaphylos - Aphids

Manzanita leafgall aphid, Tamalia coweni:

Pest description and crop damage - Manzanita leafgall aphids are grayish or greenish in color and prefer new growth. They feed on the leaves of kinnikinnick and other manzanita species (Arctostaphylos spp.). Aphid feeding causes the leaves to thicken and form bright red galls. Older galls turn brown. Severe infestations may slow the growth of the plant.

Nongall-forming aphids also may be seen occasionally on kinnikinnick. They are greenish, soft-bodied insects that may feed on leaves or stems. Honeydew, a sweet, sticky material, may be associated with aphid feeding. It may attract ants or become covered with a growth of dark, sooty mold. Severe infestations may result in leaf and twig dieback.

Management-biological control: Syrphid fly larvae are important predators of leafgall aphids, and will feed on them inside the galls. Avoid use of broad-spectrum insecticides which kill these and other beneficial insects such as ladybird beetles and parasitic wasps.

Management-cultural control: Prune off and destroy galls where seen. Avoid frequent shearing and overfertilization, which encourages succulent new growth favored by aphids. Wash other aphid pests from plants with a strong stream of water or by hand-wiping. Avoid excessive watering, and use slow-release or organic sources of nitrogen. Control ants, which "farm" aphids and protect them from predators in order to harvest their honeydew.

Season All Season
Date 2008-01-03
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Keywords: Potted plants, Roots, Planting

PAL Question:

For how long can purchased plants remain out of the ground?

View Answer:

If the plants are in pots, they can stay out of the ground as long as needed. Keep them watered and they will be fine. But if they are bare root, then you should plant them temporarily (called heeling in) in a trench until you can get them into their proper holes. The most important thing to remember is to keep the roots moist. Keeping the plants out of the sun can help reduce stress as well. If digging a trench is impractical, then cover the roots with damp towels or burlap bags. Of course, planting sooner is better!

Season All Season
Date 2006-02-23
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Keywords: Abelia, Pruning

PAL Question:

I recently bought an Abelia 'Edward Goucher.' When I got it home, I noticed a lot of the stem tips were broken off. I figured it probably happened when the salesperson pulled it away from the other plants. I tried to be very careful when I planted it, but again, some of the tips bent and broke. Then after a rainstorm the other day, I found a couple more broken. I love the plant, but is it going to be that fragile? I planted it on the southwest side of my house. Will the stems grow more sturdy?

Also, what is the best way to prune it? I thought I read that you shouldn't just trim branches but rather take some back to the ground. So if branches keep breaking, what will happen?

View Answer:

Woody shrubs purchased in nurseries often have the damage you describe, mainly from being packed into a truck for transport from the grower. Abelias are not particularly fragile when established - the branches thicken up and get stronger with time. You are right about not trimming (shearing) branches but cutting them to the ground or to a strong main branch.

The best guide to pruning abelias that I found is in Cass Turnbull's Guide to Pruning (Cass Turnbull, 2004, Sasquatch Books). She recommends removing whole branches if they are dead or damaged. When the plant is older, she suggests removing some of the lower branches that grow along the ground, and some of the taller branches that grow straight upwards. As mentioned, prune them back to a main stem. You can remove up to a quarter of the branches at a time. Pruning is best done in the winter months; pruning an abelia during the growing season will encourage it to grow even more. (In your situation, though, you might want to do some pruning during the growing season to encourage this sort of quick growth.)

Plant Amnesty's website has a section written by Cass Turnbull on pruning abelia and spirea.

Of course, if all your branches are broken, you will have to wait a year before you can do this kind of pruning - don't cut them all off. Old, overgrown plants can be cut to the ground for renewal, but a new plant probably will not survive this.

Finally, remember that this variety grows to 5 feet. Trying to keep it smaller by shearing it will lead to growth of water sprouts, and even more pruning...Cass explains all of this very well.

Season All Season
Date 2008-01-03
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Keywords: Hummingbirds, Animal-plant relationships

PAL Question:

We have a dead cherry tree in front of our house. We're sad that it died since birds loved it and it bloomed starting early winter. We'd like to find someone to replace it for us and we'd like the new tree to be small to medium in size and be a draw for hummingbirds and other birds as the old cherry tree was. What tree would you recommend to replace our old cherry tree?

View Answer:

We recommend you select a certified arborist to remove the dead tree. There is a list online here where you can narrow a search to your area.

There are some evergreen, flowering shrubs which appeal to hummingbirds, such as Grevillea, which can reach 8 feet tall, depending on the variety. Arctostaphylos (Manzanita) species and Abelia grandiflora are also possibilities.

Trees which are attractive to hummingbirds (according to Welcoming Wildlife to the Garden, by Catherine Johnson and Susan McDiarmid, 2004) include Malus species (crabapple), Crataegus (hawthorn), and Sorbus sitchensis (Sitka mountain ash).

Here are some websites with more suggestions:
Backyard Wildlife Habitat
WA Dept. of Fish and Wildlife Backyard Wildlife Sanctuary
USDA National Resources Conservation Service's Backyard Conservation tips

Season All Season
Date 2008-01-10
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Keywords: Poisonous plants, Ilex

PAL Question:

Is a holly tree toxic to animals (dogs/cats)?

View Answer:

The ASPCA website on plants which are toxic to animals lists holly (Ilex spp.), as does the Humane Society website.

According to Plant Alert, A Garden Guide for Parents (by Catherine Collins; 2001), and Plants That Poison (by Ervin M. Schmutz and Lucretia Breazeale Hamilton; 1979) the red or black berries on holly are poisonous to humans as well, and can be fatal to small children if eaten in quantity.

If you believe your dog or cat has consumed holly berries, call your veterinarian for advice as soon as possible, or call the ASPCA Animal Poison Control number, 888-426-4435 (not a free service).

Season All Season
Date 2006-03-06
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Keywords: Soil amendments, Mulching, Compost

PAL Question:

Help! My clay soil is stunting the growth of my plants. I've amended the soil with compost and manure. Is there a another method of conditioning the soil that you can recommend?

View Answer:

First and most important, it appears mulching is the best organic solution for conditioning clay and heavy soils. Organic soil conditioners include compost, well-rotted animal manures, and natural fertilizers. Planting green manures such as clover, rye grass, or vetch are also effective for breaking up large clods in clay soil over time.

Sheet composting - laying compost over the entire area to be worked and using a fork (or rototiller) to work it into the soil to a depth of 2-4 inches - is cited by the resources listed below as an efficient method of soil conditioning. Both books listed below recommend repeating this process at least twice a year, in early spring and in late fall.

Secrets to Great Soil [by Elizabeth P. Stell, 1998, (pbk)] and
The Gardener's Guide to Better Soil [by Gene Logsdon, 1975, (pbk)]

The Saving Water Partnership (the City of Seattle and other government entities) has a website full of information about improving soil.

The site includes Growing Healthy Soil.

Current thinking contradicts the notion of working compost or other amendments into the soil, as explained in this March 31, 2010 Garden Professors blog post by Professor Linda Chalker-Scott of Washington State University Extension Horticulture. She specifically takes issue with the "Growing Healthy Soil" information linked above. Here is an excerpt:
"Not only will extensive digging or rototilling destroy any soil structure you might have, it will also take out the roots of any desirable plants in the vicinity). [...] improper soil amendment can cause serious problems such as soil subsidence, perched water tables, and nutrient overloads. This last point is especially important to anyone living near aquatic ecosystems, since excess nutrients always end up in the water. Before you plant this year, find out what your soil needs before amending it. And remember that mulching is the natural (and sustainable) way to add organic matter to the soil.

Season All Season
Date 2006-12-08
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Keywords: Whiteflies, Insect pests--Identification, Insect pests--Control, Root weevils, Rhododendrons--Diseases and pests, Dahlia

PAL Question:

I have a line of Ward's ruby azaleas. The three weakest ones have a lot of tiny notches in the leaves. I seem to remember the notches from the root weevil as being larger than these. Are the tiny notches from something else?

I also noticed that some of my dahlias have splotched leaves and that when I disturb the leaves, white-looking insects fly off the leaves. These flies apparently have spread to tomatoes as well. Are these whitefly? Will they disappear after the winter or is there some control I should use to prevent them from taking over?

View Answer:

First you need to get an accurate diagnosis of your problems. If you are in King County, you can bring samples to a Master Gardener Clinic.

Oregon State University offers this information about root weevils and Rhododendron (which includes Azaleas). It describes using beneficial nematodes as a control.

According to Washington State University Cooperative Extension's publication, How to Identify Rhododendron and Azalea Problems (1984), root weevil damage to foliage is not usually a serious problem. You can check for weevils with a flashlight at night to confirm that they are the source of the notches you are seeing. There are some Neem oil-based products that may be helpful, but they must be used at the correct times of year. See WSU's HortSense page (search under Ornamentals, then scroll down to Rhododendron, and select "weevil").

As for the dahlias and tomatoes, it is important to determine exactly what the insects are before proceeding with treatment. If they are whiteflies, you can put yellow sticky traps around the plants to trap them. University of California, Davis's Integrated Pest Management site has other recommended control methods, including reflective mulch. You may not want to use insecticidal soap:
"Insecticides have only a limited effect on whiteflies. Most kill only those whiteflies that come in direct contact with them. For particularly troublesome situations, try insecticidal soap or an insecticidal oil such as neem oil or narrow-range oil. Because these products only kill whitefly nymphs that are directly sprayed, plants must be thoroughly covered with the spray solution. Be sure to cover undersides of all infested leaves; usually these are the lowest leaves and the most difficult to reach. Use soaps when plants are not drought-stressed and when temperatures are under 80 degrees F to prevent possible damage to plants. Avoid using other pesticides to control whiteflies; not only do most of them kill natural enemies, whiteflies quickly build up resistance to them, and most are not very effective in garden situations."

Season All Season
Date 2008-01-10
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June 24 2013 12:55:25