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Elisabeth C. Miller Library

Keyword: Lawns--Care and maintenance

Controlling Parsley-piert

Slowly but surely, what’s left of my untended lawn is being overtaken by a small weed with fan-shaped leaves. It reminds me of a tiny Lady’s Mantle. What is it, and is there any hope of getting rid of it without herbicide?

Your description sounds like Aphanes australis, whose common name is slender parsley-piert. The common name derives from the plant’s leaves which resemble parsley, and the French ‘perce-pierre,’ meaning ‘break (or pierce) stone.’ It thrives in dry, exposed, or barren soils. North Carolina State University’s Turf Center describes cultural control methods:
“Winter annual broadleaf weeds germinate in the fall or winter and grow during any warm weather, which may occur in the winter, but otherwise remain somewhat dormant during the winter. They resume growth and produce seed in the spring and die as temperatures increase in late spring and early summer. They quickly invade thin turf areas especially where there is good soil moisture. Shade may also encourage growth. Many have a prostrate growth habit and are not affected by mowing. A dense, vigorous turf is the best way to reduce the encroachment of winter annual weeds. First, select adapted turfgrass cultivars for your area and then properly fertilize, mow, and water to encourage dense growth.”

It sounds like lawn renovation might be a good idea. If the parsley-piert has intense competition from a happily growing lawn, it will not thrive. Seattle Public Utilities has good resources on lawn care.

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managing crabgrass

I used to have a pristine green lawn and it has since been overtaken by crabgrass. I’ve tried organic and chemical weed-and-feed products to no avail. What can I do to get the weeds out?

Local plant expert Arthur Lee Jacobson has written about crabgrass (Digitaria sanguinalis) in his book, Wild Plants of Greater Seattle (2008): “Crabgrass is difficult to get rid of because it seeds itself at an almost unbelievable rate; mowing simply makes if flower nearer to the ground. Control demands diligent weekly hoeing and pulling by hand, from July through at least September. Even a few specimens left to reseed ensure more seedlings next summer.”

According to Ecologically Sound Lawn Care for the Pacific Northwest by David McDonald (Seattle Public Utilities, 1999), weed invasions are best prevented by making a habit of aerating and topdressing to correct soil compaction and build fertile soil. He recommends that you “overseed at summer’s end with locally adapted grasses to fill bare areas with grass rather than weeds. Correct acidity or poor drainage. Mow higher (2-2 1/2 inches, or 1 inch on bentgrass), fertilize moderately with slow-release or natural products, water deeply and infrequently in the summer. Tolerate some broadleaf plants like clover and daisies. Hand weed or spot-spray problem weeds in spring or fall to stop them before they spread.”

There is additional information on crabgrass from University of California, Davis Integrated Pest Management.

Seattle Public Utilities has information on best practices for maintaining a healthy lawn.

Toxic-Free Future (formerly known as Washington Toxics Coalition) also has a helpful lawn care fact sheet that might be helpful to you.

Since the weed-and-feed approach to the problem was not effective (and chemical weed and feed should be avoided), I recommend trying some of the cultural controls discussed above (mow higher, only fertilize at appropriate times and don’t use quick release fertilizer, water less often but more deeply, improve drainage by aerating, build soil by mulching). Solarization might be an option if the problem can’t be addressed by hand-weeding combined with the other methods described.

lawns and dog urine damage

What can I do to repair the unsightly patches left in my lawn by the neighbor’s dog, which urinates there daily? Should I reseed or patch with sod?

 

First of all, if the dog’s person cannot encourage it to ‘go’ elsewhere, this will be a perpetual issue. That makes me think that it’s best to take the easiest route, which is to saturate the spots on the lawn as soon as you notice the dog has been there. A University of California, Davis publication entitled “Lawns ‘n’ Dogs” suggests prevention by flooding the small area where the dog has urinated as soon as possible after the event–keep a watering can at the ready! They recommend that you only repair the lawn if the grass is significantly burned, covers a large area, and is a cool-season non-creeping grass variety–other types of grass will regrow on their own quite easily.

Colorado State University’s Garden Notes published an article entitled “Dog Urine Damage on Lawns: Cause, Cure and Prevention.”
Excerpt:
“If the affected spots are brown, (the turf may or may not be dead):

  • Increase irrigation amount and/or frequency to help dilute salts that have accumulated in the soil. This may help still-living turf recover, and will dilute salts in those areas where the turf has been killed (allowing for more effective re-seeding).
  • When turf has been killed, the dead sod and some soil (0.5-1 inch of soil) can be removed. Re-sod the area with new grass.
  • Individual dead/damaged spots can be re-seeded as follows:In a Kentucky bluegrass lawn: Spot seed with Kentucky bluegrass (marginally effective) or perennial ryegrass (more effective). Tall fescue, K31 tall fescue, dwarf fescue, or annual (Italian) ryegrass should NOT be used for spot-seeding a bluegrass lawn.
    In a tall fescue lawn:Spot seed with turf-type tall fescue (sometimes called dwarf fescue). Perennial ryegrass can also be used, but it has a finer texture and the newly seeded spots will look different from the rest of the lawn. Do NOT use K31 fescue or annual (Italian) ryegrass for spot-seeding a tall fescue lawn.
    Fine fescue lawns: Seed with fine fescue seed. The use of perennial ryegrass or tall fescue is NOT recommended, as the spots will have a different color, texture, and growth rate.
    Zoysiagrass and bermudagrass lawns: Patch using sod from a sod farm, or by transplanting sod from an inconspicuous area of same the lawn.”

David McDonald’s guide, Ecologically Sound Lawn Care for the Pacific Northwest, has recommendations on the best grass varieties to use in our area:

“For conventional lawns west of the Cascade Mountains (the region covered by this report), most turf professionals say that mixtures of turf-type perennial ryegrasses and the fine fescues (such as chewings, creeping red and hard fescue) offer the greatest flexibility and adaptability to local conditions. A mixture of species and varieties will withstand diseases and adapt to various sites much better than a monoculture.
“In general, ryegrasses like full sun, whereas the fescues do well in sun (and are more drought tolerant) but are also among the most shade-tolerant of Northwest-adapted species. Ryegrass stands up best to heavy wear, much better than fescues, so it is the choice for sports fields. But most ryegrasses have a higher nitrogen requirement than the fescues, and so are is less appropriate for low maintenance turf. Seeding a blend of several species and varieties will allow each to thrive in the lawn area that suits it best.”

grass seed selection and planting for PNW gardens

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?

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

 

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.

Dealing with Dandelions.

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.

Garden Tip #123

Research from Purdue and Cornell University shows that autumn leaves can simply be left where they fall, shredded by a mower and allowed to mulch the lawn. Fertilize as you normally would. The shredding is essential, so don’t skip that step. If the leaf mulch is too thick, move some into your flowerbeds or compost bin. Read the research report.