How to Grow Wildflowers

Pick the right mix

“Wildflower” covers annuals, biennials and perennials that grow with little care in a given area. The best mix for you depends on your region and your site. Before buying, note whether the spot is wet, medium or dry, and whether it gets full sun, filtered sun or shade. A site with full sun and good drainage suits the most species.

Read the label closely. Many commercial mixes are mostly annuals, often non-native, which give a burst of first-year color but don’t last. The University of New Hampshire recommends spending your money on a dozen or more native perennial wildflowers plus a few native warm-season grasses. The grasses fill gaps, shelter wildlife and help suppress weeds. Adding black-eyed Susan gives some bloom in the first season while the perennials settle in. Buy a mix put together for your region: UF/IFAS stresses Florida-native, Florida-grown seed, and Texas A&M points to regional Texas mixes.

Size matters too. UNH treats about 400 square feet as the minimum for a diverse meadow. A meadow looks informal and untidy at times, so place it where it will be seen from a distance.

Prepare the site: a full season

Young wildflower seedlings stay small and low in their first year and can’t compete with established grass. UNH treats the first year as site preparation only. Common methods:

• Smothering: Scalp-mow the area in spring, then cover it with thick black plastic, tarps, or cardboard topped with mulch from mid-June to mid-September. Rake off any organic mulch before seeding so it doesn’t enrich the soil.
• Herbicide: Clemson mows close, waits for 6 to 8 inches of regrowth, sprays a glyphosate product and repeats if green growth remains. UF/IFAS repeats treatments through the season whenever weeds reach about 6 inches.
• Solarizing: Cover moist, bare soil with clear plastic through the summer. UF/IFAS leaves it on at least six weeks. This works best in hot, sunny climates and is unreliable in cool, cloudy northern summers.
• Repeated shallow cultivation or a smothering cover crop such as buckwheat on previously cultivated ground. Cover crop residue has to break down first, which usually pushes seeding to the following spring.

Whatever method you use, avoid deep tilling once the site is clear, because it brings buried weed seed to the surface. Texas A&M’s advice differs here: it suggests tilling a new planting before sowing, while UNH and UF/IFAS favor no-till and Clemson only light cultivation. Skip compost, manure and topsoil, which add nutrients and often weed seed.

Sowing

1. Measure and divide. Split large areas into plots of 400 to 500 square feet and weigh out seed for each.
2. Bulk it up. Mix the seed with sand, vermiculite or perlite so it spreads evenly. UF/IFAS uses at least 2 parts carrier to 1 part seed by volume.
3. Broadcast in two passes. Spread half the seed walking one direction and the other half walking at right angles.
4. Barely work it in. Rake no deeper than 1/4 inch, or skip raking on firm, level soil. Then roll or tamp to press the seed into contact with the soil. Don’t bury it: many species need light to germinate.
5. Mulch lightly. A thin layer of clean straw or pine needles holds seed in place and conserves moisture. UNH uses about one bale per 1,000 square feet.

Seeding rates differ. Clemson suggests 4 to 5 ounces per 1,000 square feet (around 10 pounds per acre), while UNH uses 0.5 pound per 1,000 square feet (20 pounds per acre) for its native mix. Follow the rate on your mix if it gives one.

Keep the planting moist for the first 4 to 6 weeks. Sowing before a season of regular rain is ideal. After that, water only in drought.

When to sow

Fall is preferred in most regions, because winter cold and moisture break the dormancy of many wildflower seeds and seedlings get an early start in spring. Spring sowing works but brings more weeds and slower perennial bloom. The When to Plant page covers dates by region.

What to expect, year by year

UNH’s timeline for a native perennial meadow:

• Year 1: site preparation, then sowing in fall.
• First season after sowing: seedlings are hard to tell from weeds, and few flower except black-eyed Susan. Don’t hand-weed, which disturbs seedlings. Mow in midsummer at 4 to 6 inches to cut back taller weeds.
• Next season: plants grow faster and larger, weeds become less of a problem, and coreopsis, beardtongue, bergamot and black-eyed Susan bloom.
• Year 4 and beyond: a dense, diverse meadow blooming from spring to late fall.

Clemson notes perennials are fully established by their second summer. Annuals bloom much sooner, especially from spring sowings.

Mowing and upkeep

Mow once a year in late fall or early spring, after flowers have set and dropped seed. Texas A&M warns that cutting tired-looking plants too early removes the seed that replenishes next year’s display. Clemson mows at 4 to 6 inches. UNH mows at 6 to 8 inches or higher and suggests mowing only a third to a quarter of a large meadow each year to leave winter cover for wildlife. Yearly mowing isn’t essential, but it keeps shrubs and trees from moving in.

Pull aggressive weeds and woody seedlings by hand, disturbing the soil as little as possible. Expect the mix to shift over time: some species fade while others spread, depending on weather and soil.

Common problems

• Weeds outcompete the seedlings: almost always the result of poor site preparation. Clear vegetation thoroughly before sowing.
• Nothing comes up: the seed was buried too deep or dried out. Surface-sow, roll it in and keep it moist.
• Lush weeds after fertilizing: wildflowers are adapted to lean soil, so fertilizer mostly feeds the competition.
• Bloom fades after the first year: the mix was mostly annuals. UNH recommends regional native perennials for a meadow that lasts.