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When to Plant Flowers in Denver

Because of its location and altitude, Denver's climate is variable. If you understand when to plant the various types of flowers, you can grow them in Denver with no difficulty.
  1. Annuals

    • Annuals are best planted in the Denver area after the risk of frost has passed. Although you can plant around mid-May, with 90 percent certainty that you will not experience a late frost, the last big frost on record in Denver was June 2, 1951.

    Perennials

    • Perennials should also be planted after the last frost. However, planting your perennial flowers earlier in the season will give their root system more time to develop before having to winter over. This will give them a better chance of surviving the winter.

    Bulbs

    • Bulbs should be planted in the Denver area in the fall. Colorado State University recommends planting bulbs in the Denver area in September. Bulbs bought later in the season have a higher probability of damage and may not do as well as those bought and planted earlier in the season.