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?
Archives: Plant Answer Line Q & A
Plant Answer Line questions and answers.
on growing buffalo grass in the PNW
I was interested in trying out buffalo grass (Buchloe dactyloides) ‘Legacy’ from High Country Gardens. I was wondering if you knew anyone who has tried growing it in the PNW (esp. Whidbey Island) and what they thought of its performance.
According to the Sunset Western Garden Book, buffalo grass is best suited to Sunset zones 1-3, 10, and 11. Whidbey Island is Sunset zone 5. While the Sunset book does not address ‘Legacy’ in particular, you may find that this grass is not the best choice for your location.
The Washington State Extension in Puyallup created a ranked list of good turf cultivars for Western Washington.
Additional information, from the Extension, about lawns. Note that there is an article about buffalo grass, but it is focused on whether that grass will do well in Central Washington, not Western Washington.
lawn care and controlling dandelions
I am renovating a lawn that has been completely ignored for a long time–dandelions 3 per square foot, for example. I need to know if I should use something like weed-and-feed now to kill the 1000s of weeds and wait till spring to aerate, remove the top 1/2-inch of the lawn, fertilize and re-seed. Do I need to get on this before the first frost?
Regarding your questions about lawn renovation, I have found a few options for you:
1. If the weed-and-feed product is for pre-emergent weeds, this would not work on your lawn, which already has dandelions growing actively. If the product is post-emergent, it will kill the dandelions, but if you are planning to sow grass seed, you will need to wait before sowing (different products have different guidelines, so check the directions on the package carefully). According to The Lawn Bible (by David R. Mellor, 2003), you should also make sure that the herbicide will target the weeds you have. Do not spray in windy conditions, and only treat areas which need it.
Overuse of herbicide destroys valuable bacteria and insects in the soil, so prevention is the best: mow the lawn high, which will keep weeds from getting established, as they need light to thrive; don’t scalp the lawn; water only when it is too difficult to press a screwdriver into the top 2 inches of the soil.
2. There are less toxic alternatives. Some sources say that corn gluten prevents weed seeds from sprouting. They must be wet to be activated. (It won’t work on dandelions which are already thriving in your lawn.) Please note that subsequent research suggests corn gluten may be ineffective as a weed control method. See this Oregon State University study.
According to Ann Lovejoy’s book, The Handbook of Northwest Gardening, corn gluten should be spread at a rate of 20 pounds per 1,000 square feet of lawn. Do this two or three times a year (in spring and fall, with a summer booster as needed). For ongoing weed suppression, apply it in small amounts whenever you pull up weeds (make a paste of corn gluten and water).
3. The Lovejoy book also has a recipe for fall lawn renovation:
a. Mow the existing grass as short as possible.
b. Spread 1 inch of clean crushed quarter-ten gravel (not pea gravel) evenly over the
entire surface.
c. Spread 1 inch of compost over the gravel.
d. Top-seed with a regionally appropriate blend if the lawn is thin and spotty.
e. Wait 6-7 weeks before mowing again.
A criticism of weed-and-feed products is that they will add excessive amounts of phosphorus to your lawn, which will actually encourage weed growth once the herbicide breaks down.
The Northwest Center for Alternatives to Pesticides has good information about controlling dandelions without using weed-and-feed products (originally published in the Journal of Pesticide Reform, Fall 2001).
Toxic-Free Future (formerly known as Washington Toxics Coalition) has information on an overall approach to weed control and lawn care
managing fungus gnats indoors
I need advice on how to rid my house of fungus gnats which were introduced in a bag of potting soil I used when repotting my houseplants. One plant is difficult to repot because it has long branches that cascade down the side of the pot in an intertwined mass.
I always let the soil dry out completely before potting, and also in between waterings. Recently I added a bunch of sand to the top of the soil. Would repotting again help? Is there a no-pest strip that is safe for use indoors for this insect? (I’m chemically sensitive and also concerned about the soil’s fungus).
I’m sorry to hear of your struggle with fungus gnats. I consulted
University of California, Davis Integrated Pest Management online, and
here is a link to their page on this insect and methods of controlling it. Here are excerpts which may be relevant to your situation:
Purchase and use only pasteurized container mix or treat potting soil
with heat or steam before using it; this will kill flies as well as the
algae and microorganisms they feed on. Store pasteurized potting soil in
closed containers to prevent it from becoming infested before use.
Commercially available Steinernema nematodes, Hypoaspis mites, or the
biological insecticide Bacillus thuringiensis subspecies israelensis
(Bti) can be applied to control fungus gnat larvae in container media.
North Carolina State University Extension also has suggestions on indoor control of this pest. Excerpt:
Potted plants and other types of interiorscaping are often the culprits.
Check plants to see if the soil is excessively wet. Drain any excess
water from the dish below the pot. If the weather permits, move the
plants outdoors or allow the soil to dry down (not to the point where
plants wilt). You can also drench the soil as mentioned previously. Then,
increase the interval between regular watering and the problem should
abate.
If you can possibly repot the plant(s) which had the infested soil, and
use sterile potting soil, that should help. If this doesn’t work, the
Bacillus thuringiensis (Bt) or parasitic nematodes might be an option. I
think the Bt might present problems for your chemical sensitivity, as you
would need to avoid breathing it in, and prevent it from getting on your
skin and clothing. However, the Steinernema feltiae nematodes should not
be a problem at all. One example of a source for these is Peaceful Valley Farm Supply.
I don’t think adding sand on top of the potting soil will be effective.
It might actually create a kind of crust over the top of the soil,
causing a drainage problem. If you are concerned about fungus in the
soil, using sterilized or pasteurized potting soil is a good idea. You
can try using yellow sticky traps to catch the gnats; it can’t hurt,
although it won’t completely solve the problem unless you are willing to
repot with new soil. Most garden centers sell these traps, or you can
make your own as described by New Mexico State University Extension.
You can also employ trapping techniques using yellow sticky traps. These
may be purchased, or you can make them from yellow surveyors tape or
yellow plastic butter tubs, etc., coated with vegetable oil, Vaseline, or
other sticky material. Put these traps in a window or other well-lighted
location. The adult gnats are attracted to the yellow color and get stuck
on the trap. This removes them from the home environment and reduces
their ability to reproduce. (They die on the trap.) After you catch a lot
of gnats, just discard the whole trap or wipe the insects off and reapply
the sticky material mentioned above, and you are ready to catch more.
on sourcing seeds of PNW plants
Where can the public, not agencies, purchase seeds of Pacific Northwest plants? A Missouri school teacher would like to sprout them in her classroom.
Once the teacher has a list of plants she is seeking (a list which could
be developed by looking at books on Pacific Northwest native plants, or
by visiting some of the sites linked below), there are a number of ways
of finding sources, shown below.
Washington Native Plant Society’s list of plant and seed sources
More lists of plants:
Native Plant Resources for the Pacific Northwest
Native Plant List –
Western Oregon and Western Washington
Plant Information Online – search once you have specific plants in mind.
Businesses which specialize in native plants:
on managing weevils in the garden
What is the pest that eats little notches around my Bergenia
and Heuchera? What can I do to prevent this?
It is possible your Bergenia and Heuchera are being nibbled by black vine
weevils or strawberry root weevils. Usually you would begin to notice the
damage in mid-spring. The notches won’t kill your plants, but if you have
a lot of black vine weevils and plants appear to be wilting, you may want
to attempt to control the larvae. Spraying beneficial nematodes
(Steinernema) on the surrounding soil may also help.
Below are links to information about weevils:
Black Vine Weevil from UMass Extension
Black Vine Weevils from University of California’s Integrated Pest Management site
Strawberry Root Weevil from the Pacific Northwest Insect Management Handbook
A document about Black Vine Weevil (and other root weevils) from Ohio State University Extension
Excerpt:
“Adults that feed along leaf margins produce typical crescent shaped
notches. Careful searches should be made to try and locate specimens
since several other weevils and some caterpillars can produce this same
type of notching. Moderate to light notching seems to have little effect
on plant health.
“Black vine weevils are oblong oval in shape, about 1/2-inch long and have
a short, broad snout with elbowed antennae. The body is slate grey to
blackish brown and the wing covers have numerous small pits and short
hairs. This pest is difficult to distinguish from other Otiorhynchus
weevils. The strawberry root weevil is usually half the size of the black
vine weevil, and more brown in color. The rough strawberry root weevil is
only slightly smaller than the black vine weevil but the collar just
behind the head, the pronotum, is heavily pitted.
“Female weevils emerge from soil pupation chambers late May to early July.
These weevils must feed on plant material for 21 to 45 days before they
are ready to lay eggs. After the preoviposition period has passed, the
females place several eggs each day into the soil or leaf litter nearby
suitable host plants. The weevils hide during the daytime at the base of
plants or in mulch and leaf litter near food plants. Adults may live 90
to 100 days and usually lay 200 eggs during this time. The eggs hatch in
two to three weeks and the small C-shaped, legless larvae feed on plant
rootlets. The larvae grow slowly over the summer, molting five to six
times. By late fall the larvae have matured and are about 5/8-inch long.
The mature larvae enter a quiescent prepupal stage in an earthen cell and
pupate the following spring. A single generation occurs each year.
“Strategy 1: Habitat Modification – Egg and larval survival is helped when
soil moisture is moderate to high in July and August. Heavy mulches also
help maintain critical moisture levels. Remove excessive mulch layers and
do not water plants unless necessary. Excessively damp soils in the fall
also force larvae to move up the base of the plant where girdling can
occur. Properly maintain rain down spouts and provide for adequate
drainage of soil around plants.
“Strategy 2: Biological Control Using Parasitic Nematodes – The
entomopathogenic nematodes, Steinernema and Heterorhabditis spp., have
been effective for controlling black vine weevil larvae, especially in
potted plants. Sufficient water must be used during application to wash
the infective nematodes into the soil and root zone. If the nematodes are
to be used in landscape plantings, remove a much of the mulch as possible
and thoroughly wet the remaining thatch and soil before and after the
nematode application. Applications of the nematodes in landscapes has
produced variable results.”
Sustainable lawn care
I am looking for general information on lawn care, lawn renovation, lawn fertilizer and alternatives to pesticides.
Here is information from the web pages of Seattle Public Utilities. An excerpt:
Fertilize Moderately:
Use “Natural Organic” or “Slow-release” fertilizer. These fertilizers release nutrients to feed the lawn slowly, and less is wasted through leaching or runoff into our streams. Look for the words “natural organic” or “slow-release” on the bag.
Fertilize in September and May:
With slow-release or organic fertilizers, you can fertilize just twice a year, in mid to late May and again in early September. If you choose to fertilize only once, the fall application is most important because it helps the grass grow new roots and store nutrients for next year’s growth.
How much to apply:
Washington State University (WSU) recommends that home lawns receive 3 to 4 pounds of nitrogen (in a balanced fertilizer) per 1000 square feet of lawn each year. Grasscycling can supply at least one-quarter of that. Split the rest between the May and September applications. Avoid fertilizing in the early spring because it makes lawns grow too fast (unless your lawn needs help recovering from disease or insect damage.) Wait until May.
Mow better:
Grasscycling returns valuable nutrients to the soil every time you mow! Mow high, mow often and leave the clippings to see results.
Fertilize for a healthy colored lawn”
Healthy lawns are a medium green color (top), depending on the variety of grass. The darkest green turf (bottom), which many people strive for, is not in fact the healthiest turf. Overfertilized lawns are more prone to disease, thatch buildup, and drought damage.
Test for calcium deficiency:
Soils west of the Cascades are often low in calcium. Apply lime in the spring or fall if a soil test shows a calcium deficiency or acid soil conditions (pH less than 5). Call WSU Cooperative Extension (206) 296-3900 for information on soil testing and their Home Lawns bulletin.”
If you would like to renovate your lawn, this is something you could do in the fall. Local garden writer Ann Lovejoy describes her method in The Handbook of Northwest Gardening (Sasquatch Books, 2003):
- Mow the existing grass as short as possible.
- Spread 1 inch of clean crushed quarter-ten gravel (not pea gravel) evenly over the entire surface.
- Spread 1 inch of compost over the gravel.
- Top-seed with a regionally appropriate blend if the lawn is thin and spotty.
- Wait 6-7 weeks before mowing again.
Should you decide to start afresh, here is information from the Washington State University Extension website which discusses grass seed for Western Washington gardens. Here is an excerpt:
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.
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.
University of Minnesota Extension’s Caring for Shoreland Lawns and Gardens describes best practices for caring for a shoreline lawn and garden, which includes using compost as lawn fertilizer. An excerpt:
- If possible avoid the use of chemical fertilizers. Native vegetation does not require the application of additional fertilizer. Use caution if applying fertilizers to lawns and adhere to the following guidelines:
Have your soil tested to determine how much fertilizer is needed and minimize the use of chemical fertilizers; soil test sample bags are available through the county offices of the University of Minnesota Extension Service. - Use compost or manure; this is preferable to chemical fertilizer. However, these also have the potential to damage water quality if used in excessive amounts.
- If chemical fertilizers are used, select slow-release (water insoluble) forms; see recommendations for fertilizing on next page.
- Water your lawn after fertilizing, but do not allow excess water to run off into surface waters.
- Sweep up any fertilizer spilled on hard surfaces such as walks and driveways, instead of washing it off.
- Use extra caution when applying fertilizer near surface waters; do not spread fertilizer within 75 feet of surface waters or wetlands; use a “drop” spreader and not a “cyclone” spreader to minimize the possibility of getting fertilizer directly into the water.
- Never apply fertilizers to frozen ground.
- Leave a natural vegetation filter strip of grass, trees, and/or shrubs next to the shoreline; another option would be to construct a berm along the shore.
You may find this general information about compost, from the City of Seattle Public Utilities and the Saving Water Partnership, of interest.
Here are additional links to lawn care methods. The first three are from the Northwest Coalition for Alternatives to Pesticides:
Taking Care of Your Lawn without Using Pesticides.
Pesticide-Free Techniques for Dealing with a Mossy Lawn.
From Toxic-Free Future (formerly Washington Toxics Coalition):
Choosing Fertilizers for the Lawn & Garden.
From Beyond Pesticides:
Read your “Weeds”–A simple Guide to Creating a Healthy Lawn.
plants for banks of a fish pond
We need some advice and we are hoping you can help. We would like to replant the banks of our fish pond and want to know what kinds of plants would hold a steep slope and be compatible with the fish and each other. We have a large deer and elk population and we get substantial amounts of rain. We like grass-type shrubs and we need a ground cover that will not take over and is evergreen.
From the research I have done, it seems that a pond with a sloping side is a very good idea, but if erosion is a serious issue, you may want to think about both plants and physical controls such as coconut fiber matting to stabilize the banks. The Brooklyn Botanic Garden’s guide (1997), The Natural Water Garden, has a description of using coconut fiber tubes (also called biologs) laid horizontally along a bank, which can also be used as a secure planting medium for seedlings.
As far as deer-resistant plants which may work for your site, iris and spiraea appear to be unappealing to deer, so you might want to try some of the irises which prefer moist situations, such as Iris laevigata, and Iris versicolor (blue flag), as well as Spiraea douglasii (hardhack).
Other plants which may help with preventing erosion are Lysichiton americanum (skunk cabbage), Athyrium filix-femina (lady fern), Carex obnupta (sedge), and Cornus stolonifera (red osier dogwood) or C. alba (red twig dogwood).
Some grassy or reedy plants which do well as marginal (water’s edge) plants include Acorus calamus ‘Variegatus’ (variegated sweet flag), Pontederia cordata (pickerelweed), Sagittaria latifolia (American arrowhead), and Typha latifolia (cattail). All of these are deciduous.
For evergreen plants, you could try Scrophularia auriculata ‘Variegata’ (water figwort), an evergreen perennial with cream-edged foliage. The flowers should be deadheaded to prevent self-seeding. Thalia dealbata (hardy canna) is evergreen, with long-stalked blue-green leaves and violet flower spikes.
pruning and transplanting Ceanothus
I have a mature Ceanothus ‘Victoria’ that I’d like to prune and transplant. When is a good time to do this? It seems as if it has a deep root system.
Ceanothus ‘Victoria’ can be a bit difficult to transplant because the root systems are extensive, as you noted, but it is worth a try. I have transplanted this cultivar both successfully and unsuccessfully.
I would recommend either that you do not prune them or that you wait until August. You do not want them to grow much before you transplant them, and pruning during the growing season will encourage growth. If you prune them in August, they will grow very little.
Extensive pruning before transplanting sets up competition between the root system and the upper plant (responding to the pruning), as far as the plant’s resources are concerned. After transplanting, you want energy directed toward the roots so that they might take hold and also so that growth above ground slows. If you choose to prune the shrubs, I recommend that you prune as little as possible. Prune from the inside, thinning and taking out dead branches, and removing a few lower limbs. You can also cut back some of the longer limbs, as this shrub can handle ‘heading back,’ as this type of pruning is called. Please note that this shrub is genetically programmed to get quite large, and pruning will not prevent this. Be sure the new spot can handle a shrub that wants to grow 8 to 10 feet up and out (possibly more!).
With this in mind, you can consider transplanting the shrub in the fall. I recommend October or later so that you can avoid a hot spell (which may promote upper growth and/or place the plant under stress). When you dig up the root system, retain as many of the roots and their native soil (surrounding them and holding them together) as you can. You will have to cut the deep taproot(s); that is unavoidable. The tiny, thread-like roots are more important to retain.
When you dig the hole, make it big enough to accommodate the soil around the roots as well as a bit of filler. You don’t need to add new soil; simply backfill with the soil you dug out. You may have to water a bit, even in the fall, until our rainy season begins. You don’t need to saturate the roots, but don’t allow them to dry out.
pruning Persian ironwood trees and canker affected magnolias
I have two questions. When is a good time to prune Parrotia persica?
What can I do about a canker on the trunk of a Southern Magnolia?
According to the American Horticultural Society’s Pruning and Training (edited by Christopher Brickell; DK Publishing, 1996), Parrotia persica should not need a great deal of pruning, but if you do prune, it should be from fall to early spring.
If you are growing it as a shrub-like shape, you should not thin or shorten laterals, as this will cause congested growth. If you are growing it in a tree-like form, the trunk can be cleared to about 5 feet, allowing the crown to branch. If needed, you can shorten pendulous tips to give clearance for walking beneath the tree. Once established, this tree should not be pruned. If the tree was a grafted specimen, remove any suckers.
This information from University of Florida discusses Southern magnolia (Magnolia grandiflora), and says that cankers may kill branches, but the affected branches may be pruned.
Excerpt:
“Canker diseases will kill branches. Cankers on branches can be pruned out. Keep trees healthy with regular fertilization and by watering in dry weather.”
Magnolias by Rosemary Barrett (Firefly Books, 2002) says that
“various cankers, such as nectria canker, dieback and trunk decay can all be dealt with by cutting out the dead or diseased wood. Rarely will any of these diseases cause the death of the plant.”