When to plant wildflowers

Wildflowers goes in by the calendar of your frost dates. Type your town to see the dates for your weather station.

The seed packet, in short

Wildflowers planting dates by zone

Each row uses the typical frost dates of a zone: the middle value among towns of 10,000 people or more in it. In zone 6b, for example, the typical last frost is Apr 20, so the first step for wildflowers, plant seed, falls Mar 23 to May 4. Towns in one zone can differ by two weeks, so your own town's dates above are the better guide.

Good to know about wildflowers

• Fall or winter sowing lets seed get natural cold treatment; seed sown in late summer can sprout and then be killed by frost.
• Loosen only the top half inch of soil, scatter seed mixed with sand for even coverage, then rake lightly and press it in; do not bury it.
• Keep seed moist for 4 to 6 weeks while it sprouts and settles in.
• Clear weeds well before sowing; site preparation is often a full season of work.

How to plant wildflowers

• Most wildflowers need full sun and well-drained soil; woodland species are the exception and take light shade.
• Skip fertilizer, compost and manure for meadow plantings; extra fertility mostly feeds weeds, and meadow flowers do fine in lean soil.
• Avoid deep tilling, which brings buried weed seed to the surface; loosen only the top few inches.
• After broadcasting, roll or tamp the area for good seed-to-soil contact, then add a thin layer of straw.
• Once established, mow the meadow about once a year in late fall or early spring, leaving 4 to 8 inches of stubble.

Types that change the timing

• Seed mixes usually blend annuals, biennials and perennials; annuals give most of the first-year color.
• Perennial wildflowers often do not bloom until the second year, and some take two to three years just to sprout.
• Many off-the-shelf mixes contain non-native plants; a mix of species native to your region supports local pollinators.

Common mistakes

• Sowing into existing weeds or turf; wildflower seedlings cannot outcompete them, so clear the site first.
• Expecting the planting to look the same every year; the fastest spreaders often take over after a year or two.
• Choosing a mix that does not match the site, such as moisture lovers on a dry slope.

Warm and cold regions

• Zones 3-6: Sow in mid to late fall, after a killing frost, so seed lies dormant over winter and sprouts in spring; spring sowing about a month before the last hard frost also works.
• Zones 7-8: Sow September through November as soil cools toward 40 F, or March to late April if you can keep seedlings watered.
• Zones 9-10: Fall sowing timed with cool-season rains works best; spring sowing faces more weed and heat stress.

First harvest

Annuals in a mix flower the first summer; perennials sown in spring usually wait until the second growing season, and a full meadow takes about three years.

Many meadow perennials germinate better after a cold, moist winter in the soil, which fall or dormant sowing provides; some need 6 to 12 weeks near 40 F.