Tickseed

Coreopsis is the perennial that rewards neglect. Plant it in lean, well-drained soil in full sun and it will bloom for months — often from June until the first hard frost — with no fertilizer, no deadheading regimen, and only the most occasional watering. The flowers are golden yellow daisies, sometimes two inches across, held on wiry stems above ferny foliage. Bees and butterflies visit them constantly. It is one of the most generous plants you can put in a pollinator border.

The main thing to understand about coreopsis is that it blooms itself to death if you let it. A plant left to set seed all summer will exhaust itself by August, and the show ends. Deadheading — cutting or snapping off spent flowers before they form seed heads — keeps the plant in bloom production instead of seed production. You don't need to be religious about it, but walking through the bed once a week with pruners in hand makes a noticeable difference in the length of the season.

Soil preferences matter more than most gardeners expect. Coreopsis evolved in sandy, rocky ground with low fertility, and it still prefers those conditions. Rich garden soil amended with compost and manure produces lush foliage that tends to flop over in the first rainstorm, and the plant makes fewer flowers because it has enough nitrogen to grow leaves instead. If your soil is heavy or fertile, plant coreopsis in a spot where you haven't amended in a few years, or mix sand into the bed to lean it out.

The other reality is that coreopsis grandiflora and its hybrids are shorter-lived than true prairie perennials like echinacea or rudbeckia. A clump may bloom enthusiastically for two or three years, then start to die out in the center, leaving a ring of tired stems and bare ground in the middle. This is normal. Divide the clump in early spring every three years, replanting the outer sections and composting the dead center, or let the plant self-sow and pull out the old clump when it looks finished. The seedlings tend to come back reliably if you don't mulch too heavily.

Transplant after your last frost date — coreopsis tolerates light frost but establishes faster in warm soil. Space plants about eighteen inches apart; they fill in quickly and a dense planting is more prone to fungal issues in humid climates. Water during the first few weeks until the roots take hold, then leave it alone. Overwatering or overhead irrigation in humid weather can encourage powdery mildew on the foliage, though it rarely kills the plant — it just looks tired by late summer.

In fall, cut the plant back to a few inches above the ground after it has finished blooming or after the first frost. The dried seed heads are attractive to finches if you want to leave them standing for a few weeks, but cutting them back before winter tends to reduce disease carryover and keeps the clump tidier. Mulch lightly if you're in zone 4 or colder; in warmer zones the plant needs no winter protection.