Smooth purple coneflower

Year-round

Smooth coneflower is not from Texas, but it grows well as a garden perennial in Houston when it gets good drainage and a little relief from full afternoon sun.

• Give it full sun to a few hours of afternoon shade so Houston's heat and humidity do not stress it as much as full all day sun would.
• Break up Houston's heavy clay before planting. Work several inches of compost into the bed, or plant on a slight mound, so water drains away from the crown.
• Water regularly through the first growing season while roots establish, then ease off. This plant tolerates drought and poor soil once it is settled in.
• Watch for leaf spot and crown rot during Houston's wet, humid stretches. Both show up more here than in the plant's native mountain range.
• It has special value to native bees according to the Xerces Society, so a well drained bed still earns its keep for pollinators even outside its home range.

Fall

Fall is a second good planting window in Houston's mild climate, and a chance to tidy the bed before winter while leaving some seed heads for later.

• Houston's cooler fall weather is a good second window to plant new coneflowers or divide crowded clumps, giving roots months to settle in before next summer's heat.
• Trim back any leaf spot damaged foliage, but leave a good number of seed heads standing rather than cutting the whole plant down.
• Ease off watering as temperatures drop. This plant does not want soggy soil heading into Houston's wetter winter months.
• Skip heavy fertilizer in fall. A light compost topdressing is enough going into the plant's slower season.

A tidy fall cutback that still leaves a few seed heads standing reads as intentional, not overgrown, which helps avoid a violation letter.

Winter

Houston winters are mild but wet, which is harder on this plant's roots than a cold, dry winter further north. Keep the crown dry and watch for the occasional hard freeze.

• Houston rarely gets cold enough to fully finish this plant's winter dormancy, but wet soil during our cool, damp winters is harder on the crown than cold alone.
• Leave any standing seed heads through winter if you did not cut them back in fall.
• If a hard freeze is forecast, pull mulch back a few inches from the crown first, then add a fresh layer over the roots so moisture does not sit against the base of the plant.
• Hold off on winter fertilizing. The plant does not need feeding while it is dormant or slowed down during Houston's mild winter.

Fresh mulch and a few standing seed heads read as an intentional winter planting, not a neglected bed, which helps avoid a violation letter.

Spring

Spring is planting and early growth season in Houston. Get new plants or divisions in the ground early and set up good drainage before the heat arrives.

• Plant new coneflowers or divide older clumps in late winter to early spring, before Houston's heat ramps up.
• Work compost into heavy clay at planting time, or set the crown slightly above grade, so spring rain does not pool around the roots.
• Keep soil evenly moist but not soggy while roots establish this first spring.
• Check new growth for slugs and snails after rain. Houston's humid spring weeks bring them out.
• Skip heavy fertilizer. A light compost topdressing is enough, and overfeeding pushes weak, leggy growth in Houston's mild spring.

Summer

Summer is bloom season, but Houston's heat and humidity are harder on this plant than the Appalachian Piedmont it comes from. Give it some afternoon shade and stay ahead of fungal problems.

• Give it afternoon shade during peak summer. Houston's heat and sun load are stronger than in the plant's native range.
• Deadhead spent blooms to keep it flowering into late summer, but leave some flowers standing toward the end of the season.
• Water deeply during dry stretches rather than a little every day. Shallow, frequent watering does not hold up under Houston's summer heat.
• Check leaves for leaf spot in humid summer air and remove affected foliage so it does not spread through the bed.
• Keep mulch a few inches back from the crown. It holds moisture and keeps roots cooler without inviting rot.

Deadheading through summer keeps the bed looking tended, which reads as intentional, not neglected.