When Can You Start Planting Flowers in Colorado?
- Colorado's high altitudes and highly unpredictable weather make it an exciting place to live and garden.
- Tender perennials and annuals, such as petunias, impatiens and geraniums, are best planted a week or two after the last frost, usually in late May to June.
- Denver-area gardeners and those on the western slope may grow plants that are hardy to USDA Zone 5.
