Best Peonies for Colorado

A peony clump returning in spring is a quiet reward in a Colorado yard. These plants are built for cold winters, so the real choices are between herbaceous hybrids and tree peonies, and between a sunny open bed and a sheltered corner. Those choices decide how well a plant settles in.

Best Peonies to Grow in Colorado

Peonies suit Colorado because they need a cold winter rest to flower, and most of the state delivers it across USDA zones 3b-7b. Herbaceous hybrids and tree peonies can fit, and the choice comes down to the spot you have and the look you want.

Herbaceous Hybrid Peonies

These are the classic garden peonies, sold as Paeonia hybrids in pink, purple, red and white. They bloom in May and June and stay a tidy height, with foliage that looks good long after the flowers fade.

Give them full sun. Each year the stems die back to the ground, so the plant renews itself from the roots with no help from you beyond a fall cleanup.

Tree Peonies

Despite the name, a tree peony (Paeonia suffruticosa) is a deciduous shrub with woody branches that stay standing through winter. It tends to bloom earlier than the herbaceous kinds, and the flowers are larger.

In Colorado, tree peonies prefer light shade and a protected location. A spot out of the wind, perhaps on the east side of a wall or fence, suits them well. Mature plants can reach 3 to 5 feet and usually need no staking, since the woody branches hold up the heavy blooms.

Flower Forms to Look For

Within the herbaceous group there are hundreds of varieties, and the differences show in the flower. Single, double, bomb and anemone forms all exist, in whites, pinks, reds, corals and yellows, and some are fragrant while others are not.

Heavy doubles can bend after a rain, so a support keeps them upright. Singles and anemone forms hold their heads better with less fuss.

Cut-Flower Varieties

If you want armloads of stems for the house, look for varieties sold for cut-flower production rather than landscape use alone. Choosing early, mid and late bloomers gives you flowers over a longer season.

Along the Front Range, the large, fragrant blooms often open in late May or early June, which sets the start of that cutting window.

How to Choose a Peony for a Colorado Garden

Start with the spot, not the catalog photo. Light, shelter and how much room the plant will have at full size narrow the field quickly.

Time matters too. Herbaceous peonies are simple plants, but they do ask for a fall cleanup, while a tree peony keeps its framework.

Conditions vary across Colorado, so judge heat tolerance against your own site. Light, shelter and mature size also belong in the decision.

Which Peonies Suit Different Parts of Colorado

Colorado stretches from plains to high mountains, and the same peony does not meet the same conditions everywhere.

• Front Range: Denver sits at 5,280 feet on the plains, and herbaceous hybrids and tree peonies both settle in. Blooms often open in late May or early June.
• Mountain towns: Growing seasons run far shorter and frost can arrive in July, so ask local gardeners which peonies handle the site well. Tuck any tree peony into a sheltered spot.
• Western Slope: Conditions differ again from the Front Range, so a visit to a local garden center or county office will tell you which varieties neighbors have kept going.

Wherever you live, the shelter around the plant often matters as much as the town it sits in.

Peony Buying Mistakes to Avoid in Colorado

Putting a Tree Peony in the Open

A tree peony set in a bare, windy bed has to carry its woody stems through the whole winter with no cover. The plant will likely struggle there.

Choose a protected location with light shade instead. A wall, fence or larger shrub nearby gives that shelter.

Planting the Roots Too Deep

A peony planted too deep may bloom poorly or not come up at all. The pink buds on a bare-root crown can look as if they should be buried for safety.

Keep those eyes near the soil surface when you set the plant, and settle the soil gently around the roots.

Ignoring Mature Size

A small potted peony at a garden center says nothing about its adult size. Herbaceous hybrids stay shorter, but a tree peony can grow 3 to 5 feet tall.

Check the plant tag before you buy, and leave room for the full size. Crowded plants are harder to move later.

Where to Get Peony Advice in Colorado

Colorado State University Extension offers research-based guidance for the state’s gardeners, and your county office adds local knowledge about altitude and soil.

• The extension website has plant guides you can read before you shop, so a quick look before buying helps you pick the right type.
• Your county office can tell you how peonies are doing in your own town, and a visit in early fall, before planting, gives you time to act on the advice.

Common Questions

When Should You Plant or Divide Peonies in Colorado?

September and October suit planting and dividing, in fall before the ground freezes. That gives the roots time to settle before winter.

Do Peonies Bloom the First Spring After Planting?

A newly planted or transplanted peony may not bloom the first spring. Give it time to settle in, and keep it at the right depth so it has a chance to flower later.

When Should You Cut Back Peonies in Colorado?

Cut herbaceous peonies back in October or November, after a hard freeze has killed the foliage. Take the stems down to within a couple of inches of the ground and dispose of the debris. A tree peony keeps its woody stems and is never cut back.