Bulbs, rhizomes, corms, and tubers (usually commonly grouped together as “bulbs”) make wonderful additions to the garden.
About Bulbs
Bulbs are generally categorized as hardy vs. tender:
- Hardy Bulbs: These bulbs respond to winter’s chill to produce flowers in spring or summer.
- Tender Bulbs: These bulbs generally don’t like freezing weather and are dug up and stored indoors over the winter or (if they’re hardy in your area) grown outdoors year-round. If they are stored, the bulbs can be replanted in the spring.
As with other garden plants, you can push the limits of your hardiness zone by protecting your bulb beds with a thick layer of mulch. If winter hardiness is a concern, look for cultivars specifically bred to be cold-tolerant. The zones below serve as a general guide, but new varieties are constantly being developed that bend the rules!
Bulb Growing Guide
Here’s a handy guide to the winter hardiness, planting season, and bloom season for some common landscape bulbs.
| Bulb Name | Grow Zone | Bulb Type | When to Plant | Bloom Season |
|---|---|---|---|---|
| Allium | 5 | Bulb | Fall | Spring/Summer |
| Amaryllis | 9 | Bulb | Fall | Spring |
| Anemone | 4 | Tuber | Fall | Spring |
| Belladonna Lily | 7 | Bulb | Spring | Late Summer |
| Caladium | 9 | Tuber | Spring | Summer |
| Calla | 7 | Rhizome | Spring | Summer |
| Canna | 8 | Rhizome | Spring | Summer |
| Colchicum | 5 | Corm | Summer | Fall |
| Corn Lily (Ixia) | 6 | Corm | Fall | Spring |
| Crocosmia | 7 | Corm | Fall | Summer |
| Crocus | 7 | Corm | Fall | Spring |
| Crown Imperial | 3 | Bulb | Fall | Spring |
| Cyclamen | 5 | Tuber | Fall | Spring/Summer |
| Daffodil, Narcissus | 4 | Bulb | Fall | Spring |
| Dahlia | 8 | Tuberous Root | Spring | Summer/Fall |
| Dutch Iris | 5 | Bulb | Fall | Early Summer |
| Elephant Ear | 9 | Corm | Spring | Summer |
| Freesia | 9 | Corm | Fall | Indoors-Spring |
| Gladiolus | 8 | Corm | Spring | Summer |
| Glory of the Snow | 3 | Bulb | Fall | Early Spring |
| Grape Hyacinth | 4 | Bulb | Fall | Summer |
| Harlequin Flower | 9 | Corm | Spring | Summer |
| Hyacinth | 3 | Bulb | Fall | Spring |
| Iris | 4 | Rhizome | Fall | Summer |
| Lily | 4 | Bulb | Fall | Summer |
| Magic Lily | 5 | Bulb | Summer | Fall |
| Peacock Flower | 8 | Corm | Fall | Spring/Summer |
| Ranunculus | 7 | Tuberous Root | Spring | Summer |
| Siberian Squill | 3 | Bulb | Fall | Spring |
| Snowdrop | 3 | Bulb | Fall | Early Spring |
| Snowflake | 4 | Bulb | Fall | Spring |
| Star of Bethlehem | 4 | Bulb | Fall | Spring |
| Trillium | 4 | Rhizome | Fall | Late Spring |
| Tuberous Begonia | 10 | Tuber | Spring | Summer/Fall |
| Tulip | 3 | Bulb | Fall | Spring |
| Winter Aconite | 4 | Tuber | Fall | Early Spring |
