Coreopsis is a hardy plant suitable for growing in USDA plant hardiness zones 4 through 9. As such, coreopsis winter care isn’t a difficult task, but a bit of protection will ensure the plant remains hale and hearty throughout even the toughest winter, ready to burst forth when temperatures rise in spring. Read on to learn how to winterize a coreopsis plant.
About Coreopsis Overwintering
Care of coreopsis in winter actually takes place during autumn. Once you’ve taken care of a few critical steps, you can stay indoors and enjoy a good book with the assurance that you, and your coreopsis plant, are snug and warm.
The number one question when it comes to getting coreopsis plants ready for winter is “Should coreopsis be cut back in autumn?” Many sources will tell you to cut coreopsis nearly to the ground in autumn. While to cut back or not is largely a matter of personal choice, it isn’t always the healthiest thing for the plant.
Leaving dead growth in place during winter actually provides a certain amount of insulation for the roots. It also creates texture and a lovely cinnamon color that lasts through the winter months, until you prune the plant in spring. Be sure to remove wilted blooms, however, especially if you want to prevent rampant reseeding.
If the unkempt look drives you crazy, go ahead and cut coreopsis back. Cutting back may also be a wise decision if your garden tends to have fungus or other moisture related problems. Use care and leave at least 2 or 3 inches (5-8 cm.) of stems in place, as cutting too severely before a difficult winter may kill the plant.
Winterizing Coreopsis Plants
Surround the plant with plenty of mulch in autumn, regardless of your decision to cut back or not. Applying at least 2 to 3 inches (5-8 cm.) is preferable, and more if you live in the northern reaches of the growing zone.
Don’t fertilize coreopsis after late summer or early fall. This isn’t a good time to encourage new, tender growth that can be zapped when temperatures drop.
Continue to water coreopsis and other perennials until the ground freezes. It may sound counterproductive, but roots in moist soil can withstand freezing temperatures better than those in dry soil. When it comes to winterizing coreopsis plants, watering and mulching are the most important steps you can take. No other coreopsis winter care is necessary, as the plant will be in a dormant stage of growth.
Remove the mulch as soon as frost no longer threatens in spring. Don’t wait too long because damp mulch can invite pests and disease. This is a good time to apply a bit of general-purpose fertilizer, topped by a thin layer of fresh mulch.