Today, I noticed some tulips coming up in my garden and realized spring is just around the corner. I live in the Denver Colorado area and the general rule around here is that you are safe to plant annuals and new perennials after Mother’s Day, but I usually always take a chance and plant my Colorado flower garden a little earlier.
The following map shows the different hardiness zones in mainland USA. Colorado is in zones 4-6. Specifically, the Denver area is in zone 6a. At the nursey or in a catalog, be sure the plant you want to purchase will survive in the zone you are planting it in.

So, will Tulips grow in a warmer climate than zone 6? Only if they get an amount of cold required – which Is usually 2-3 months. Some years, I will bury some Hyacinths or Tulips in pots in the garden then dig them up and bring them in around late January/early February. The aroma of the Hyacinths in winter is magnificent. You can also purchase forced bulbs from the grocery store but it’s fun to do it yourself as well.
Here are my favorite flowers to plant in Zone 6 with some growing facts about each:
Petunia
- Annual Plant from seed
- Purchase six packs from the nursery.
- Blooms throughout the Summer
- Seed – but purchase six-packs from the nursery.
- Requires lots of sun.
Lilium (Tiger Lilly, Day Lilly)
- Perennial
- Plant in the Fall
- Blooms in the Spring
- Bulbs
- a must for your Colorado flower garden
Tulipa (Tulip)
- Perennial
- Plant in the Fall
- Blooms in the Spring
- Bulbs
Zinnia
- Annual
- Plant in the early spring
- Blooms throughout the summer
- Seeds
Geranium
- Perennial if brought inside before frost.
- Plant indoors by seed
- Blooms Throughout the Summer
- Seeds
Impatiens
- Annual
- Plant by seed
- Blooms throughout the Summer
- Seed or six pack from the nursery
- Most do well in shady areas.
Rosa (Rose)
- Perennial
- Plant throughout the Summer
- Blooms mostly late Spring
throughout the Summer - Asexual Grafting
- All Colorado flower gardens should have roses.
Dahlia
- Perennial if dug up in the fall.
- Plant in the Early Spring
- Blooms mid to late Summer
- Tubers
Gladiolus
- Must be dug up before freeze.
- Replant in the Spring
- Blooms mid to late summer
- Bulbs
Delphinium
- Perennial
- Plant anytime throughout the growing season
- Blooms in the Spring
- Seed
Muscari (Grape Hyacinth)
- Perennial
- Plant once in the Fall
- Blooms in early spring
- Spreads throughout the garden
I will add more interesting plants to this list as the season goes on. If you have any questions or comments about my Colorado flower garden, please don’t hesitate to contact me. I love to chat about gardening!
Also, I would love to hear about your favorite plants in your garden wherever you are, whatever the climate.