Why Did My Beautiful Coreopsis Die This Winter?

In order to answer the question “Why did my beautiful Coreopsis die this winter?” it’s important to understand a few things about the Coreopsis family in our gardens.

I’ve grown this amazing daisy family member – common name is Tickseed –  for almost as long as I’ve been gardening (ahem… over 45 years now) professionally. And I’ve learned a few lessons about it along the way.

To begin with, almost every one of these plants is a long-blooming perennial but they do come with different lifespans.

The Longest Lived Coreopsis In My Gardens

Both Coreopsis verticillata and Coreopsis rosea are heavy bloomers and very long lived in my USDA zone 4 garden. In fact, they are the best of the long-blooming family.

They’re both hardy into USDA zone 4 (although C. rosea  – a pink flowering plant may not be quite a hardy or long-lived as C. verticillata – a yellow bloomer)

Other Coreopsis In Garden Centers

You’ll often find C. grandiflora and C. lanceolata in garden centers and these tend to be shorter-lived plants.

They have larger flowers though and with regular deadheading and pruning, they’ll bloom all summer.

You can see all kinds of Coreopsis plants here.

The Modern Hybrids

In order to obtain different colors, modern breeders introduced tender Mexican species to the breeding mix. So if you’re purchasing some of the more colorful hybrids, these are variably hardy

So What You’re Saying…

Yes, some of these modern hybrids are not as tough as the older plants. The Southern genetics are lovely but they’re not really tough enough for some northern gardens.

And yes, nursery marketing people aren’t necessarily making this fact part of their sales pitch.

My Best Advice

Read the label. Good marketing people put the USDA hardiness rating on the label (If you’re in a USDA 4, you’re mostly out of luck with the new ones)

Here’s The Secret To Making Coreopsis Tougher

Grow them in the full sun.

Grow them with perfect drainage. This plant thrives in well-drained, sandier soils. Any clay or standing water is going to make them weaker going into the winter.

If your garden is too wet over the winter (too many freeze-thaw cycles in the spring) or with irrigation or any moisture around the crown of the plant, the survival rate will be low.

In short:

  • This is a plant for full, hot sun.
  • It wants perfect drainage with no clay soil.
  • It doesn’t want wet mulch around the crown over the winter.

And even then, it may not live over the winter as marketers tend to overestimate how tough their perennial plants are.

But at least now you understand why your fancy, expensive Coreopsis died on you.

For more practical perennial tips, check this out.

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