keeping cats out of flower beds

How can I keep cats out of my flower beds? They keep using them as a litter box. I’ve heard to use cocoa hull mulch or eggshells since cats don’t like to step on them. Is that safe, and will it work?

One of the main results I found is that cats are unpredictable, so you might want to try a
few possibilities. The most reliable approaches seem to revolve around creating
smells, textures, or situations that cats dislike.

We don’t recommend using cocoa beans or eggshells to prevent cats from going into your flowers.
Cocoa bean mulch is toxic to dogs and possibly other pets. In fact, it has more concentrated theobromine per ounce than most chocolate products. This page from the ASPCA (now archived) has more information, and it is further confirmed at Snopes.com, a site that evaluates word-of-mouth knowledge and urban legends.
Eggshells, on the other hand, are nontoxic, but seem likely to attract pests and thus create a new and different
animal problem.

Instead, there are a number of other solutions you might try. One that a
librarian here has had success with is planting strong-smelling plant like
lavender (Lavandula spp.) or other herbs (but NOT catmint, also known as Nepeta!).

Another tactic that might not offend your nose is to make the area unpleasant to
use as a litter box. In particular, you can make it unpleasant for cats to walk through and dig in. Laying chicken wire or hardware cloth out over the garden bed is said to be successful sometimes, though it would be difficult to do after plants were established. Another possibility would be making a ground-level lattice of thorny branches, like rose prunings, around established plants. Other possibilities include a stone mulch or some other kind of bristly mulch, such as prickly pinecones. This article discusses these and other cat repellents.

Please note, though, that we don’t recommend all of the ideas you will find there, like scattering mothballs in your garden, which is just as likely to be toxic to you as to the cats. You don’t want to harm yourself or anything else!

If you are looking for a long term solution with no toxicity and some fringe
benefits like doing your watering for you, motion activated sprinklers are
highly recommended as a cat repellent.

cherry tree blossoms in February?

Is it possible that I’m seeing cherry trees flowering this early (mid-February)? Some have white flowers, and some are pink.

It is certainly true that things may be flowering early when we have a mild winter. In 2014, the famous cherry blossoms in the University of Washington’s Quad began opening on March 13, and the winter of 2015 was warm, so they may be opening earlier than that. While it is possible you are seeing flowering ornamental cherries (Prunus species), they are easily confused with their cousins in the same genus, flowering ornamental plums–extremely common street trees in Seattle–most of which are definitely flowering now. Ornamental pears (Pyrus) are also flowering now. They have white petals, and might be mistaken for cherry trees as well but the distinctive odor of pear blossoms is a big clue to their true identity: acrid, astringent, and just plain stinky!

The Vancouver Cherry Blossom Festival offers some pointers on how to tell the difference between cherry and plum blossoms. Most cherry blossoms aren’t noticeably fragrant, while plum blossoms are fragrant. Cherry blossoms usually have small splits or indentations at the ends of their petals. Note, however, that the book Japanese Flowering Cherries by Wybe Kuitert (Timber Press, 1999) says cherry “petals are mostly [emphasis mine] retuse,” that is, not all of them have a shallow notch or split on the ends of the petals.

Project BudBurst, a citizen-science phenology project, offers this distinction: apple blossoms have 3 to 5 styles whereas cherries have one. And what is a style? It is the part of the pistil between the stigma and the ovary. Brooklyn Botanic Garden also has a helpful guide to flowering trees that are not cherries.

According to the British Natural History Museum, one unifying characteristic of cherries is “flowers in clusters with stalks all arising from a central point, or arranged along a short stem, or in spikes.”

plants for narrow planting areas

I am redoing the narrow planting areas (2-3′ wide) on either
side of our 20′ long entry. Garages from next door townhouses butt up
against the outer edge on each side, causing morning sun and afternoon shade on one
side, and vice versa on the other side. I have picked out some
euphorbias, heucheras, and carexes which should do well. I’m wondering
if I should have some taller, more dramatic plants to offset these and if
you have any suggestions of ones which might work. Also, any bulb ideas
would be appreciated.

Have you considered putting up trellises on one or both sides? Then you
could grow vines which require little width, but still have the
advantage of height. You could also grow taller plants (maybe some
grasses like Miscanthus or even a well-restricted–using root
barrier–Bamboo) in containers, and keep them shaped to suit the narrow
space. Some shrubs and trees are naturally narrow or fastigiate in growth
habit.

Here is a list of narrow plants compiled by local garden designer Chris
Pfeiffer, c2005. Some will be too wide for your planting area, but you
might want to research those that fit the site.

American arborvitae ‘Rheingold’ (Thuja occidentalis ‘Rheingold’) 5’h x
3′ w

Barberry ‘Helmond Pillar’ (Berberis thunbergii f. atropurpurea ‘Helmond
Pillar’) 6’h x 2’w

Boxwood ‘Graham Blandy’ (Buxus sempervirens ‘Graham Blandy’) 8’h x 1-1/2’w

English yew ‘Standishii’ (Taxus baccata ‘Standishii’) 4’h x 1-1/2’w

Irish yew (Taxus baccata ‘Fastigiata’) 20’h x 4’w

Japanese holly Jersey pinnacle (Ilex crenata ‘Jersey Pinnacle’) 6’h x
4’w

Japanese holly Mariesii (Ilex crenata ‘Mariesii) 3’h x 1-1/2’w

Dwarf yeddo rhaphiolepis (Rhaphiolepis umbellata ‘Gulf Green’) 3-4’h x
2’w

Heavenly bamboo ‘Gulf Stream’ (Nandina domestica ‘Gulf Stream’) 4’h x 2’w

Japanese euonymus ‘Green Spire’ (Euonymus japonicus ‘Green Spire’) 15’h x
6’w

There are also a good number of tall perennials you might try, such as
(for your afternoon sunny side) Helenium, Verbascum, Baptisia,
Eupatorium, and bulbous plants like Allium and Eremurus, and for your
shadier morning sun side, Macleaya, Digitalis, Filipendula ulmaria,
Anemone x hybrida, Actaea (formerly called Cimicifuga), Lilium martagon, Thalictrum, and Veronicastrum.

There are many excellent gardening books you could consult for ideas.
Since you have a small, narrow space, I highly recommend local garden
writer Marty Wingate’s book, Big Ideas for Northwest Small Gardens
(Sasquatch Books, 2003). You are welcome to visit the Miller Library,
where you can do further research and also borrow books.

gardening with children and children’s gardens

I am interested in information about gardening with children and gardens designed for children. Can you recommend some relevant web sites and articles?

Below are some useful web sites about children’s gardens. They include actual children’s garden web sites which may have garden maps or plans as well as information about how the garden was designed, and horticulture sites with information about gardening with children.

The Edible Schoolyard Project

Magnuson Park Children’s Garden

kinderGarden

The Helen & Peter Bing Children’s Garden

Children’s Garden at the Morton Arboretum

The Midway Plaisance Children’s Garden

Ithaca Children’s Garden

Each year, the National Children & Youth Garden Symposium, takes place at varying locations.

You may wish to visit the Miller Library and search the Garden Literature Index, which has an article about past years’ symposia (see abstract here: 2006 Youth Garden Symposium. Robbins, Heather American Gardener; Sep/Oct2006, Vol. 85 Issue 5, p12-15
The article presents the highlights of the 2006 annual American Horticultural Society’s National Children & Youth Garden Symposium held in Saint Louis, Missouri. It cites the implications of the high number of participants in the event. The issues discussed at the educational sessions in the symposium include building children’s gardens and community gardening. Attendees were given the opportunity to explore the Missouri Botanical Garden, the event’s host garden.)

Below is just a sampling of other articles from the “children’s gardens” search results:

1. Gardening on the curriculum? Why not? By: West, Cleve. Garden, Jan2007, Vol. 132 Issue 1, p13-13, 1/2p; (AN 23649207)

2. Lewis Ginter Botanical Garden. By: Day, Susan. Birds & Blooms, Oct/Nov2006, Vol. 12 Issue 5, p54-55, 2p, 1 map, 4c; (AN 22575160)

3. SCAPE’S GARDEN OF DISCOVERY. HD: Hospital Development, Mar2006, Vol. 37 Issue 3, p6-6, 1/4p; (AN 20303088)

4. The Best Backyard In The World. By: McGuire, Leslie. Landscape Architect & Specifier News, Mar2006, Vol. 22 Issue 3, p58-65, 8p, 1 map, 8c; (AN 20532564)

5. THE ACTIVITY MATRIX. Landscape Architect & Specifier News, Mar2006, Vol. 22 Issue 3, p60-63, 4p, 8c; (AN 20532565)

6. Children’s Garden Consultants: A New Model of Engaging Youth to Inform Garden Design and Programming. By: Lekies, Kristi S.; Eames-Sheavly, Marcia; Wong, Kimberly J.; Ceccarini, Anne. HortTechnology, Jan-Mar2006, Vol. 16 Issue 1, p139-142, 4p, 2 charts; (AN 20620955)

7. Duke Garden. By: Stewart, Joann. Daylily Journal, Winter2005, Vol. 60 Issue 4, p414-415, 2p, 4c; (AN 19479979)

8. Cultivating gardeners. By: Benson, Sally D.. American Nurseryman, 9/1/2005, Vol. 202 Issue 5, p4-4, 2/3p; (AN 18031480)

9. Fall for Fun: New Children’s Garden. By: Sherman, Marilyn. Chicagoland Gardening, Sep/Oct2005, Vol. 11 Issue 5, p78-79, 2p; (AN 18096223)

10. Kid’s paradise. By: Patrick, John. Gardening Australia, Apr2005, p22-26, 5p, 9c; (AN 16593169)

There are also articles available in landscape architecture and urban planning publications which we do not have in our library, but which you might find at the University of Washington Libraries. I searched the Avery Index to Periodicals and came up with quite a few potentially useful results. Here are some examples:

Child’s play: the Ian Potter Foundation Children’s Garden is a new component of the very successful observatory precinct at the Royal Botanic Gardens Melbourne [Australia] / Bruce Echberg. :photos., site plans. Landscape architecture Australia 2006 Nov., n.112, p. 49-52, ISSN 1833-4814.

Footprints of school gardens in Sweden / Petter kerblom. photos., drawings, plans, site plans. Garden history 2004 Winter, v.32, n.2, p.[229]-247, ISSN 0307-1243.

We also have many books available here at the Miller Library on gardens for children. Our annotated booklist (154 pages)may be of interest.

landscaping around septic systems

We have a new house that we have to landscape around. The biggest problem is that we have to be careful what we plan due to the septic system. It is an evaporation system, with two huge cement tanks buried under the ground in the front of the house and plastic pipes running through the side yard. We are planting grass in a rectangle right above the biggest bunch of the plastic pipes, but what can go around it or by the cement tanks that will not grow long roots and dig into it? In looking at the planting information on the packages and in my Western Garden Book, nothing seems to mention root depth.

Below is an article entitled What to Plant Over the Septic System by Mary Robson (originally published in her Regional Garden Column for Washington State University Extension, December 6, 1998):

“As more and more people move into rural areas, questions about septic systems and landscaping have become quite common. This column deals with some of the basics. A new brochure from Washington Sea Grant called: Landscaping your Septic System, offers considerable detail on the subject and provided much of this material.

“First, be sure that the septic field is clearly identified, and you know where the reserve area is. Keep all construction away from these areas. Understanding the functioning of the system is vital. Get information. (Some of it is available in video form.) The drainfield will not work well if overloaded with extra surface water, so be certain that it is not in the path of downspout run off or irrigation systems.

“Sunlight and air circulation also help the drainfield perform properly. Avoid surrounding it with tall trees. (Some shade is fine, but you would not plant an oak on the edge of a drainfield.) Set up some barriers so that it is not compacted by frequent foot traffic. Occasional mowing or moving through the field to check the system is certainly fine, but you do not want the drainfield in the middle of a heavily used path.

“There are advantages to using plants over the drainfield. Plants do help provide oxygen exchange and contribute to evaporation necessary in the drainfield area. Choose plants with shallow, non-invasive roots. You do not want breakage or damage in pipes from root intrusions.

“Grasses are most commonly recommended for the septic area. Lawn can be attractive. Do not overload the system by watering it a lot. Meadow grasses or a mixture of turf grasses like perennial rye and some broadleaf flowers (such as yarrow) can also look good and require little maintenance. Several mixes sold as Eco-Turf or Fleur de Lawn have these components.

“Small, shallow-rooted ornamental grasses (for instance, Festuca ovina
\’Glauca\’ 4-10 inches) can also be good looking. Very tall grasses like Stipa gigantea are not appropriate. Avoid over-active plants like English ivy (Hedera helix), which is becoming a menace in forested areas by moving in and stifling trees.

“Edible crops are not suggested. Vegetable gardening requires frequent cultivation, and digging in the drainfield area is inadvisable. Also, the brochure notes that: Sewage effluent is distributed through the soil in the drainfield area. Any root vegetables planted in this area may be directly exposed to septic tank effluent.

“Other possibilities are low-growing ground covers. Some, such as bugle weed (Ajuga reptans) and vinca (Vinca minor) grow vigorously and would fill in quickly. The native kinnikinnick (Arctostaphylos uva-ursi) grows well in full sun but is slow to establish. A mulch around the plants may help with weed control while the plants spread.

“The green growing layer over the septic tank helps the system to function, adds to the appearance of the landscape, and should, ideally, be set up to allow easy monitoring and maintenance. Keep landscaping simple and straightforward, remembering that the object is the good performance of the system.”

To get more information on septic systems, contact your local health department. The brochure Landscaping Your Septic System (pdf) is available through the Sea Grant Program.

Here are links to publications that might also be helpful:

Mounds: A Septic System Alternative

Understanding and Caring for Your Sand Filter System

Care and Feeding of Septic Tanks

raking leaves in the Fall

I have heard that raking to clean up leaves in the fall is no longer a recommended practice, and that it is more sustainable to leave the leaves alone, to decompose in place. Can you provide information supporting this?

This is a complex issue without a single simple answer. Letting leaves lie in place is fine in some situations and not in others. Undisturbed leaves can be a beneficial mulch in the garden, but not all leaves, and not in all circumstances.

Here are a few suggestions:

Don’t leave diseased or insect-affected leaves on the ground. (As a precaution, I always rake up and remove leaves of fruit trees.)

Be aware that a thick mat of leaves can make a great hiding place for slugs and snails, and early stages of stink bugs. Learn to recognize their pearly little eggs!

If you have thick or leathery leaves (such as oak and magnolia), a mulching mower might be a good way of breaking them down to use as mulch.

If leaves are slippery or are going to obscure uneven terrain that might cause people to trip or fall, rake them.

If you do decide to collect leaves into a pile, raking is a better method than using a leaf blower (and if you must blow, use an electric or battery-operated blower, which is still noise pollution but at least not air pollution).

In their 2014 book The Living Landscape: Designing for Beauty and Biodiversity in the Home Garden (page 146), Rick Darke and Doug Tallamy do advocate letting leaves lie in the garden, but they recommend running over them with a mower first if you want to have finer material for mulching (so as not to smother fragile plants)—which means they would need to be raked into a mowable pile first. Another way to make leaves more useful as mulch is to compost them for a year—which would also require raking them up and putting them in a pile. Generally, though, the authors favor the let-it-lie philosophy: “In many places, the most conserving, functional, low-maintenance approach to autumn leaves is to let them lie where they fall. This is exactly what happens in unmanaged forest ecosystems. Though a too-heavy leaf layer can have a negative effect on delicate herbaceous plants, most trees and shrubs and a wide range of sturdy perennial herbs grow well under natural leaf fall.”

I will point out that a tiny urban garden is quite different from an unmanaged forest ecosystem, so sometimes we need to rake leaves where they impede access to paths, steps, sidewalks, etc. And again, consideration should be given to preventive measures. Don’t let lie the leaves of any plant you know to be struggling with pests and diseases.

can wood chip spread diseases?

I have two 40′ trees diseased with Phytophthora lateralis that I am having removed tomorrow. Can I chip the branches and spread them in my garden or will this spread the disease to other plants?

Although the following information from Washington State University Extension refers to a different species of Phytophthora, I imagine that the same precautions hold true.

Excerpt:
“P. ramorum can be spread to other hosts through air, water, rain, soil and plant debris. People can move it via plants, plant material, soil, plant products, wood, woodchips, dirty shoes, and water. P. ramorum does best in cool, wet climates (like ours).”

A resource from Oregon State University confirms this for both commonly found species of Phytophthora fungus:

Generally, one does not need to worry about plant diseases being spread by wood chips, because “they cannot compete well with wood-decay fungi. Uncomposted plant materials can, however, carry two important diseases of woody plants: Port-Orford-cedar root rot, caused by Phytophthora lateralis, and Sudden Oak Death (Phytophthora ramorum). Many diseased Port-Orford-cedar trees are disposed of by chipping, and mulch made from these chips can spread disease to healthy plants.”

Witches’ brooms

I have purchased a Larix laricina ‘Blue Sparkler.’ It appears to be a dwarf larch but I can’t find any information about it. Could you point me toward a reference?

According to an article by Kathryn Lund Johnson in The American Gardener, volume 87, no. 6. (2008) entitled “Wicked and wonderful: witches’ brooms,” Larix laricina ‘Blue Sparkler’ is a witches’ broom cultivar. It was introduced in 1993, and is a dwarf deciduous larch with “a dense habit that is reminiscent of miniature fireworks. Its blue green needles turn gold in autumn, then drop. In 10 years, it can grow three feet high and two-and-a-half feet wide.”

Witches’ brooms are a type of deformity that can occur for a number of reasons, according to the article, including dwarf mistletoes, fungi, viruses, bacteria, and aphids. Witches’ brooms on conifers are used as a source for propagating new cultivars. The propagator takes a cutting from the broom, and this ‘scion’ is “either rooted directly or grafted to young conifers that serve as the ‘understock.’ When grafting, the wound is given a year to heal. The understock is then removed and a new plant stands in its place.” This method was pioneered by Sidney Waxman, a professor of plant science at University of Connecticut, Storrs. He is responsible for developing the ‘Blue Sparkler’ tamarack you are growing.

Iowa State University has a page of information about the phenomenon of witches’ brooms.

growing and caring for Cornelian cherry trees

Can you tell me how to grow Cornelian cherry? Do I need more than one tree to get fruit? Also, what kind of soil and fertilizer does it need?

Cornelian cherry, or Cornus mas, is not especially fussy about type of soil, but prefers well-drained moist soil that is somewhat rich. According to Lee Reich’s Landscaping with Fruit (Storey, 2009), the tree is at least partly self-fruitful, but planting a second tree (a different cultivar or clone) will increase fruit yield. I don’t think there are particular fertilizer needs for this tree, but you can provide a mulch of compost in spring or fall if you wish. Reich says to “plant this tree carefully, keep weeds at bay at least for the first few seasons, water as needed during the first season and you’ll have little else to do for your tree beyond enjoying looking at it and harvesting the fruits.”

The local website of Great Plant Picks has information about this tree.

Washington State University at Mount Vernon’s fruit research center offers a list of cultivars tested in 2007:
Cornus mas

“Elegant”
“Olga”
“Pioneer”
“Red Star”
“Sevetok”
“Yevgenii”

sourcing non-GMO seeds

I read an article recently that said some of my favorite seed companies are now owned by Monsanto. I don’t want to use genetically modified seeds in my home garden, so I’d like to know where I can find more information on the sources seed companies use for the seed I am buying.

You may be referring to the January 2009 issue of the PCC Newsletter regarding Monsanto purchasing many of your favorite garden and farm seed catalogs. Territorial Seeds, Johnny’s Seeds, Park Seed, Burpee, Cook’s Garden, Spring Hill Nurseries, Flower of the Month Club, and Audubon Workshop are not owned by Monsanto or Seminis. PCC subsequently posted a retraction.

The folks at Organic Seed Alliance are a great resource on this issue. Here is what they suggest:
“For gardeners interested in buying non-GMO seeds, the best bet is to purchase seeds from seed companies who sell only organic seeds and who have signed the Safe Seed Pledge.”

For further reading on the subject, see this February 2005 article (now archived) by Matthew Dillon from the Rodale Institute on Monsanto’s purchase of Seminis. Environmental News Network also has information about a September 2008 discussion forum with writer Michael Pollan and Monsanto CEO Hugh Grant.