A bundle of bare-root roses is ready for the ground as soon as the soil can be worked in spring. Roses in Colorado follow a short list of dependable dates: planting and pruning in April, feeding through summer, and a soil mound over the crown in November. Those dates, and the types that cope with Front Range winters, make up the rest of the year.
When to Plant Roses in Colorado
Bare-root roses go in first, in April and May while they are still dormant, and potted roses follow later in spring. Around Denver the last spring frost falls between May 1 and May 11, which is why a young rose that has already leafed out needs a cover on a cold night.
- In April, bare-root roses are planted dormant as soon as the ground can be worked, repeat-blooming roses are pruned, and winter protection starts coming off gradually.
- In May, bare-root planting can carry on, and potted roses can go in later in the season.
- From May through July, established roses are fed, which keeps growth steady through the main flowering stretch.
- By mid-August, feeding stops, so new soft growth has time to firm up before cold arrives.
- In November, soil is mounded over the crown, usually around Thanksgiving, to carry the canes through the hard freezes.
The first fall frost around Denver arrives between September 30 and October 12, and soft growth from late feeding is vulnerable when cold arrives. Across the state, USDA hardiness zones run from 3b to 7b, so a yard in the mountains or on the Western Slope will not match these dates exactly.
Colorado — the year and the numbers
- State
- Colorado
- USDA zones
- 3b-7b
- Last spring frost
- May 1 to May 11
- First fall frost
- September 30 to October 12
- Annual rain
- 15 in
- Lawn zone
- transition-season
- Source
- NOAA NCEI 1991-2020 Climate Normals, 32F freeze probabilities · Denver
Which Roses Grow Best in Colorado?
The roses that last here are the ones that shrug off winter. Cold winters decide which types need extra work, and hybrid teas, floribundas and grandifloras need added winter protection.
Hardy shrub roses sit at the other end, because they carry fewer demands into the cold months.
| Rose type | How it does in Colorado | Why |
|---|---|---|
| Hybrid teas, floribundas and grandifloras | Need extra protection in cold winters | Extra winter protection is often recommended for them in Colorado |
| Hardy shrub roses such as Knock Out or the Explorer series | Perform well without extra protection | They are hardy enough to skip the winter mound |
| Old garden roses, ramblers and many climbers | Bloom once a year | They flower on last year’s wood |
That last row changes the pruning. Once-blooming roses are cut right after they bloom, never in early spring, because spring pruning removes the wood that carries the flowers. Floribundas and modern shrub roses repeat bloom and follow the April schedule instead.
When to Prune, Feed and Protect Roses in Colorado
Rose care follows a clear seasonal rhythm. Pruning waits for spring, feeding runs through the growing months, and the winter mound goes on late and comes off gradually.
Wait until spring for the real shaping, when swelling buds help show which canes survived winter. Here the focus is on the key dates.
| Task | Best months in Colorado | Why then |
|---|---|---|
| Pruning repeat-blooming roses (hybrid teas, floribundas, modern shrub roses) | April, or May if it slips | Pruning just ahead of the last hard frost avoids new growth caught by a killing frost |
| Feeding roses | May, June and July, with April and August also fine | Regular feeding fuels the growing season, and it stops by mid-August to avoid tender late growth |
| Putting on winter protection | November, or October and December if needed | Mound the soil once nights drop to 20°F for several days |
| Taking winter protection off | April, or May if cold lingers | Remove it gradually, once the danger of hard frost has passed |
Planting bare-root roses fits in April and May, as covered above. The soil mound helps protect tender roses through winter.
How Rose Care Dates Change Across Colorado
Altitude and the mountains shape the rose season more than anything else in the state, and the dates above are anchored to Denver.
- Denver and the Front Range plains: These dates fit the plains best, where spring pruning lands in April and the winter mound goes on in November.
- The mountain towns: Seasons run far shorter and frost can show up in July, so planting waits later in spring and the winter mound goes on sooner.
- The Western Slope: The season differs again from Denver, so local dates are worth checking before the first planting or pruning.
Higher ground pushes every task later in spring and earlier in fall, and hardy shrub roses make more sense there than tender hybrid teas.
Where to Get Rose Advice in Colorado
Local help is available for diagnosing problems and testing soil before planting. Colorado State University Extension publishes rose guidance for the state, and each county has its own office.
- The extension website has seasonal rose care guides, useful before pruning in spring or mounding in fall.
- The county extension office can test your soil, which is worth doing before planting bare-root roses in April.
- A photo or sample of a troubled rose can go to the county office, and the earlier in the season it arrives, the more can be done about it.
Common Questions
What Fertilizer Works for Roses in Colorado?
Colorado guidance calls for an all-purpose fertilizer such as 8-10-8, applied every four to six weeks during the growing season.
How Deep Should the Soil Mound Be Over a Rose?
In Colorado, the recommendation is to mound soil over the crown eight to ten inches deep once nights fall to 20°F for several days.
Should You Cut Back Tall Roses Before Winter?
If roses have grown very tall over summer, they are more likely to suffer snow and wind damage. In Colorado, the guidance is to prune tall plants by one-third of their height in November, and otherwise to wait for mid-April.