Microclover Lawn in Washington: Zone 6–9 Guide
Washington is oddly split on clover — and it’s worth knowing why. WSU’s turf publication calls white clover a lawn weed. WSU’s own Master Gardeners list clover as a recommended eco-lawn alternative. Both are right; they’re answering different questions.
- USDA zones: 6–7 (east) · 8–9 (Puget/coast)
- Climate: Wet fall–spring, very droughty summer
- WSU turf view: Clover treated as a weed
- WSU eco-lawn view: Clover a lawn alternative
- Herbicides: Kill clover — must skip them
- Mow: 2.5–3 in (WSU: less water use)
- Eastern WA: Hot, arid — irrigate
- Pet-safe: Yes
Why WSU says two different things about clover
Read WSU’s Home Lawns publication and you’ll find white clover described bluntly: it’s sometimes sold in lawn seed mixes, it’s susceptible to kill by most common lawn herbicides, and it “is usually treated as a lawn weed.” Read WSU’s King County Master Gardener tip sheet on lawns and you’ll find clover listed among the low-growing alternatives — alongside yarrow, creeping thyme, moss and chamomile — noted as a component of eco-lawn seed available from local nurseries. Both statements come from Washington State University, and both are accurate. The turf publication is answering “how do I maintain a uniform grass lawn?”, where clover is a contaminant. The Master Gardener sheet is answering “how do I reduce lawn maintenance and water use?”, where clover is a tool. You have to decide which question is yours.
The choice you’re actually making
Here’s the practical consequence, and it’s the most important thing on this page: a clover lawn and a conventional weed-and-feed programme cannot coexist. WSU is explicit that clover is killed by most common lawn herbicides — so the moment you pick microclover, you’re opting out of broadleaf herbicide use, permanently. WSU also notes a well-fertilised lawn suppresses clover, which cuts the same way: heavy nitrogen pushes the clover out. What you get in exchange is a lawn that fixes its own nitrogen, needs less feeding, and supports pollinators. That’s a genuine trade, not a free upgrade. If you’re committed to a flawless, herbicide-managed monoculture, don’t buy microclover. If you want a lower-input Washington lawn, it’s an excellent choice — just go in with both eyes open.
Washington by region
| Region | Zone | Microclover notes |
|---|---|---|
| Puget Sound & coast (Seattle, Olympia) | Zone 8–9 | Best fit — cool, wet most of the year; droughty summer |
| Central WA (Wenatchee, Yakima) | Zone 6–7 | Hot, arid — irrigation essential; seed mid-Aug–mid-Sept |
| Eastern WA (Spokane) | Zone 6 | Colder, drier — more winter dieback; irrigate in summer |
Across Washington, microclover is a cool-season, blended lawn component — easiest west of the Cascades, irrigation-dependent in the hot, arid centre and east.
How to plant microclover in Washington
Late summer to early fall is the window statewide — WSU recommends mid-August to mid-September for seeding (with April–May as a second option), because the cooler seasons keep the seed bed moist for germinating seed. In central and eastern Washington, time your seeding around when irrigation water is turned on or off for the season. Overseed microclover into perennial ryegrass or fine fescue rather than going pure; mow low first for seed-to-soil contact, then broadcast and keep the surface moist.
Use Rhizobium-coated seed. Afterwards, follow WSU’s own cultural advice, which happens to suit clover perfectly: mow at 2.5–3 inches (taller turf shades the soil and uses less water), leave your clippings (grasscycling returns roughly 2 lb of nitrogen a year), split irrigation across the week to avoid runoff, and remember Washington’s rainfall is concentrated in fall through spring with a very droughty summer. And skip the herbicides.
Is a microclover lawn right for your WA yard? (fit-check)
Good fit if: you’re west of the Cascades, want a lower-input lawn that feeds itself and supports pollinators, and are willing to give up broadleaf herbicides and heavy nitrogen entirely.
Reconsider if: you want a flawless herbicide-managed grass monoculture — WSU’s turf guidance treats clover as a weed for exactly that reason — or you’re in hot, arid central/eastern Washington and hoping to skip summer irrigation. You can’t have both clover and weed-and-feed.
The bottom line: Washington’s own university says two things about clover, and both are true. WSU’s turf publication treats white clover as a lawn weed — killed by common herbicides, suppressed by good fertilisation — while WSU’s Master Gardeners list clover among the eco-lawn alternatives for gardeners who want less mowing and watering. The deciding question is which lawn you actually want. Choose microclover and you’re choosing a lower-input, self-fertilising, pollinator-friendly lawn, and giving up the weed-and-feed programme for good. Seed mid-August to mid-September, blend with ryegrass or fine fescue, mow at 2.5–3 inches, grasscycle, and expect to irrigate through Washington’s very droughty summer — much more so east of the Cascades.
Frequently asked questions
Is clover a weed in Washington lawns?
It depends who at WSU you ask — and that’s not a dodge. WSU’s Home Lawns turf publication states white clover is sometimes sold in lawn seed mixes but “is usually treated as a lawn weed,” noting it’s killed by most common lawn herbicides. Meanwhile WSU’s King County Master Gardener lawn tip sheet lists clover among the low-growing lawn alternatives found in eco-lawn seed, for gardeners reducing maintenance and water use. Both are correct: clover is a weed if your goal is a uniform herbicide-managed grass monoculture, and a valuable component if your goal is a low-input lawn. Decide which lawn you want, then be consistent.
Can I use weed-and-feed on a microclover lawn?
No — and this is the single most important thing to understand. WSU notes white clover is susceptible to kill by most common herbicides used for lawn weed control, so any broadleaf weed-and-feed will damage or destroy your clover. WSU also observes that a properly fertilised lawn helps suppress clover, meaning heavy nitrogen works against you too. So planting microclover is a decision to stop using broadleaf herbicides and to keep nitrogen low. In exchange, the clover fixes its own nitrogen and reduces your feeding needs. It’s a legitimate trade — but you can’t run both systems at once.
When should I plant microclover in Washington?
Mid-August to mid-September is the prime window, with April–May as a second option — WSU recommends these seasons because they’re cooler and the seed bed is easier to keep moist for germinating seed. In central and eastern Washington, time your planting around when irrigation water is turned on or off for the season. Overseed into your existing lawn rather than starting over: mow low for good seed-to-soil contact, broadcast microclover into perennial ryegrass or fine fescue, and keep the surface moist through germination. Use Rhizobium-coated seed so nitrogen fixation begins, and avoid herbicides before or after seeding.
Does microclover need watering in a Seattle summer?
Yes, some — despite the rainy reputation. WSU notes that although the majority of Washington’s rainfall comes in fall, winter and spring, summers here are very droughty, so irrigation still matters. Microclover holds colour better than plain grass under drought stress, but it does not tolerate high heat and drought indefinitely and will thin without water in a hard summer. WSU advises splitting irrigation across two or three applications a week to reduce runoff, and mowing at 2.5–3 inches — taller turf shades and cools the soil, resulting in less water use. In hot, arid central and eastern Washington, summer irrigation is essential rather than optional.
Do I need to fertilise a microclover lawn in Washington?
Very little. Microclover fixes its own nitrogen through Rhizobium bacteria, which is the whole point — UMD Extension notes it can reduce roughly one fertiliser application a year. Add to that WSU’s grasscycling advice: leaving your clippings on the lawn returns approximately 2 pounds of nitrogen per year to the turf stand. Between the clover and the clippings, a Washington microclover lawn needs little or no synthetic nitrogen. In fact you should keep nitrogen deliberately low, since WSU notes a well-fertilised lawn suppresses clover — feed it heavily and you’ll lose the very plant you paid for.
Lower input, by choice
For a Washington lawn, a microclover-fescue mix blends into cool-season turf, or overseed microclover seed into existing ryegrass or fescue; fine fescue suits shadier, wetter PNW sites. Compare the neighbouring Oregon guide (where OSU’s eco-lawn research is more enthusiastic), learn ground-cover use in the microclover ground cover guide, or plan for cold in the microclover winter guide.
Washington’s climate, WSU’s differing turf and eco-lawn positions on clover, and regional irrigation needs cross-checked against Washington State University Extension, WSU Extension Master Gardeners, and University of Maryland Extension. Where a state’s own experts disagree, we show both.
Sources
- Washington State University Extension — Washington State University Extension (IN-STATE, the blunt turf view): WSU’s Home Lawns pu
- WSU Extension Master Gardener Program (King County) — WSU Extension Master Gardener Program, King County (IN-STATE, the eco-lawn view): for Puge
- Washington State University Extension — Washington State University Extension (IN-STATE practice: mowing, water and grasscycling):
- WSU Extension (Chelan & Douglas Counties) — WSU Extension (IN-STATE, eastern/central Washington): Central Washington has a hot, arid c
- University of Maryland Extension — University of Maryland Extension (what microclover is): microclover refers to smaller vari