Ecolawns for the Pacific Northwest

Tom CookOSU Horticulture

2007

What should lawns be?

• Do all lawns have to be pure grass?• Do lawns have to be a mono-culture?• Are there good broadleaf weeds?• Are there niches for different kinds of

lawns?• Who decides what is appropriate?

After looking at lawns throughout the Pacific Northwest west of the Cascades for many years, it has become clear to me that most homelawns, parks, cemeteries, school grounds, etc. are in no way pure stands of grass. Most are a mixture of a fairly wide array of grasses and a fairly predictable list of dicot plants (broadleaf weeds) that are well suited for the conditions under which the lawns are being maintained. In the worst case scenario, the result is an ugly, weedy mess. Often, however, I see very attractive and apparently stable mixtures of plants that seem to perform well with minimal water, fertilizer, and mowing.

The idea of ecolawns is to try to simulate this ultimate climax vegetation to produce a lawn that is functional, reasonably attractive, and requires fewer rather than more inputs to produce anacceptable lawn.

There are many roadblocks in pursuing this goal. The biggest one (as noted on the slides that follow) is that many desirable components for an ecolawn are not in the commercial trade. The ecolawns described below are based on components that are available for purchase. With concerted effort, a host of new species may one day be available, resulting in much more sophisticated mixtures that are truly self sustaining.

The evolution of ecolawns

Naturally occurring ecolawns

T Cook photo

This is an old lawn that has evolved on its own to a fairly steady state climax. It is characterizedby partial shade, heavy soil, excess winter moisture, low fertility, and regular mowing with clippingsreturned. The components include bentgrasses, rough bluegrass, white clover, and Veronicachameadrys. All components are well suited to the site and tolerant of mowing.

Veronica chameadrys ecolawn flowering in spring

T Cook photo

All Veronicas have beautiful flowers inspring. The rest of the year the plants blend in nicely with the grass to produce a lawn that is easy to care for.

Naturally occurring bentgrass/lawn violet ecolawn

T Cook photo

Lawn violets are another plant well suited to ecolawns. They don’t blend as well with grass as some other plants, but the flowers more than make up for that in early spring.Like many compatible lawn plants violets can self seed and spread vegetatively.

T Cook photo

Naturally occurring bentgrass/ Galium ecolawn

One of the most intriguing plants with potential as part of an ecolawn is Galium verum.As this photo shows, Galium is extraordinarily drought tolerant and can stay green without any irrigation at all in the Willamette Valley of Oregon. It mixes well with grass and looks very much like a conventional lawn for most of the year. It producessmall yellow flowers in summer, but they are not very showy. It’s weak link is poor seed production. It can spread by seed or vegetatively by rhizomes. If seed wereavailable, it would be a great addition to an ecolawn mix.

This site is extremely dry with only False dandelion and Galium verummanaging to stay green by late summer. The grass in the foreground isRat-tail fescue, which is a winter annual. Galium verum typifies desirable plants that are not commercially available. T Cook photo

Lady’s Bedstraw, Galium verumT Cook photos

This stand of Galium is dense and green even without any irrigation. The yellow flowers develop in summer, but rarely cover the entire stand.

Constructed Ecolawns 1.Base of Perennial ryegrass

2.Common yarrow

3.Clovers

4.English Daisies

5.Others?

The first step in developing commercial ecolawn mixes is to find dicot and grass components that can be purchased in the trade. Our initial trials were based on the ingredients listed above.

Common Yarrow Achillea millefolium

T Cook photo

Yarrow is fairly common in lawns and gardens where it has demonstrated excellent droughttolerance. It blends well with grass and is well adapted to regular mowing. Best of all it is very persistent.

Strawberry clover Trifolium fragiferum

T Cook photo

In our early trials we used a variety of Strawberry clover called ‘Fresa’ developed at NewMexico State University. Shown here it is dense and persistent and well adapted to mowing. It has excellent drought tolerance. Unfortunately, it was not a commercial success due to poor yields in production fields. Now most strawberry clovers used in ecolawn mixes come from the forage trade. They tend to be ranker growing, but still work okay.

A new micro-white clover is now available that will likely fill the void created by loss of ‘Fresa’ strawberry clover.

English daisy Bellis perennis

T Cook photo

English daisy is a common component of drought stressedlawns throughout western Oregon and Washington. The wild types are very hardy and tolerate summer drought by going dormant. They can spread by seed or vegetative propagation.For our mixes we have had to use daisies out of the flower trade. These are not as hardy and the stand tends to fade out over a three to five year period after planting.

Daisies in spring

T Cook photo

Yarrow and White clover in summer

T Cook photo

Clver and yarrow are the most drought hardy components in commercial mixes. Theywork well in summer to obscure the now dormant ryegrass, while presenting a green cover. Normally, we irrigate once per month starting in mid June.

Yarrow vs Ryegrass after 5 weeks without water

T Cook photo

Performance at Corvallis on clay soil

Mowing goal: 1 per 3 wks 2” with mulching rotary

Mowing reality: 1 per 2-4 wks

Irrigation goal: 1 per mo. June, July, Aug, Sept 4 total

Irrigation reality: 2-4 total per year

Pest control goal: no treatments

Pest control reality: no treatments on clean sitesone treatment sequence in year two on dirty sites

Corvallis

4 irrigations per summerMowed every 3 weeks

Wilsonville

No irrigation3 mowings?

T Cook photos

With modest water in summer ecolawnshave stayed green. Without any water they go dormant like most other lawns.

Ecolawns in practice

T Cook photo

This is a commercial mixture planted around the renovated Weatherford Hall on the OSUcampus. This is typical of a young ecolawn in mid spring in the Willamette Valley of Oregon.

Ecolawns in practice

Spring is the time to see the flowers. In summer, ecolawns look more like conventional grass lawns from a distance.

Ecolawns in practice

After nearly a month without water, the grass lawn planted to hard fescue is partially dormant and generally unattractive. The ecolawn mixture dominated by yarrow and clover still looks green. This is the major strength of the ecolawn mixtures, the ability to look green under droughty conditions.

Where do ecolawns fit in the big picture?

So far we have done little more than assemble mixtures based on plants we thought might workand knew were commercially available. The interest on the part of the public has been surprisingly strong and has come from all over the USA.

There are obvious short comings with current mixes. They contain a limited number of species, the daisies tend to disappear over time, users don’t seem to understand that reduced input doesn’t mean no input, etc. Still, people do continue to plant them and many are very pleased with the results.

To move beyond this ‘first try’ stage, a lot of work needs to be done. We need to continue searching for new and better components. We need to figure out how to grow and produce seed from the promising components and the production process needs to be commercialized.

Since ecolawns need to be regionally specific if they are to persist over time, researchers in other parts of the country need to begin the process of evaluating potential mixes for their regions. Beforethat can happen, turf people have to buy into the concept as one more piece of the puzzle as far as sustainable lawns are concerned. Right now there is a powerful bias toward pure grass turf in the turf research community and the public.

I don’t ever see ecolawns replacing conventional grass lawns but I hope to see more options for lawns than we have at the present time. My goal is to see people have acceptable lawn groundcovers that don’t require intensive applications of water, fertilizer, or pest control products. Expanding our conceptof lawns beyond just grass may increase the chances of that happening.