When to Plant Black-Eyed Susans in Colorado
Cheerful golden blooms that attract butterflies and tolerate drought. A backbone of the low-maintenance perennial garden.
The Short Answer
Colorado Frost Dates
Your planting dates depend on which part of Colorado you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Front Range (Denver) | 5a, 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
| Western Slope | 4b, 5a, 5b, 6a | May 10 - Jun 1 | Sep 15 - Oct 5 |
| Mountain Regions | 3a, 3b, 4a, 4b | Jun 1 - Jun 20 | Aug 25 - Sep 15 |
Black-Eyed Susans Planting Schedule for Colorado
Front Range (Denver) (Zones 5a, 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
Western Slope (Zones 4b, 5a, 5b, 6a)
Average last frost: May 10 - Jun 1 · Average first frost: Sep 15 - Oct 5
Mountain Regions (Zones 3a, 3b, 4a, 4b)
Average last frost: Jun 1 - Jun 20 · Average first frost: Aug 25 - Sep 15
Growing Black-Eyed Susans in Colorado
Black-Eyed Susans in Colorado's Climate
Black-eyed Susans are native wildflowers that thrive in cold-climate conditions. Plant divisions or nursery plants from spring through early fall. They handle poor soil, drought once established, and cold winters without complaint. Leave seed heads standing through winter for bird food and visual interest.
Soil Considerations for Colorado
Alkaline clay soils common along Front Range. Rocky, thin soils in mountains. Amend heavily with compost and sulfur to lower pH.
Colorado Climate & Growing Season
High altitude means intense sun but cool nights. Low humidity. Hail risk in late spring. Short but intense growing season at elevation. Black-Eyed Susans can handle frost well, which is an advantage in Colorado's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Colorado: Front Range (Denver) (5a, 5b, 6a) has a last frost around May 1 - May 15, while Mountain Regions (3a, 3b, 4a, 4b) sees frost end around Jun 1 - Jun 20. This difference matters for black-eyed susans — but black-eyed susans handle frost well, so the timing difference is less critical.
Growing Tips
Leave seed heads standing through winter for birds and visual interest. Self-seeds freely — deadhead if you don't want more.
Companion Planting
Plant black-eyed susans alongside these companions for better growth:
The Bottom Line
Last reviewed: March 29, 2026