What to Plant in May in Colorado
By Jodi Torpey
May weather is so unpredictable, it seems like there are three gardening seasons in the span of 31 days. Make the most of this unsettled weather by dividing the month into thirds. Plan for planting in early May, the middle of May and the end of May.
In early May it’s still cool enough to plant transplants of cool-season vegetables like lettuce, cabbage, cauliflower, broccoli, and Brussels sprouts.
Plant trees, shrubs and container roses in early May before the weather heats up.
Add perennial fruit crops to the landscape such as blackberries, currants, gooseberries, grapes, raspberries and goji berries. Grow blueberries in acidic soil to get the best results.
Perennial plants, vines and ornamental grasses can be planted during the entire month, but the earlier the better. Cooler weather helps reduce transplant shock.
Mid-May is a good time to start planting summer bulbs, sometimes called tender bulbs. Buy gladiolus, dahlia, canna, lily, freesia and allium. These bulbs and tubers will bloom in summer and then need to be dug up and stored indoors over winter.
Purchase and plant bedding annuals like petunias, and herbs like basil, chives, parsley, dill, oregano, thyme, rosemary and sage.
Seed new bluegrass lawns, overseed thin lawns or plant sod.
Wait until mid-to-late May before planting warm-season fruits and vegetables. Use a soil thermometer to make sure the vegetable garden soil is at least 50 degrees (and nighttime temperatures are a reliable 55 degrees) before planting hardened tomatoes, peppers, eggplants, squash, corn, beans, pumpkins and cucumbers.
Plant flowers from seed or buy transplants for marigolds, sunflowers, zinnias, nasturtiums and cosmos.
Add drought-tolerant perennials to the garden like ice plants, salvias and penstemons.
