The Best Time to Plant Bulbs in Wisconsin

Plant gladiolus bulbs in Wisconsin after danger of frost has past.

Hardy, spring-flowering and summer-blooming bulbs can be grown throughout Wisconsin and left in the ground year-round. Divide hardy bulbs immediately after flowering if they need to be divided Tender summer-flowering bulbs should be dug up and stored over winter in Wisconsin and re-planted in spring.

Spring-Flowering

Bulbs that bloom in spring, such as tulips, daffodils, crocus and hyacinth, must be planted the previous fall. In Wisconsin, plant these bulbs from mid-September to late October, or at least three to four weeks before the ground freezes for the winter.

Hardy Summer-Flowering

Plant hardy, summer-blooming bulbs like lilies from early spring through midsummer for blooms the same year. Although iris are treated similar to lilies, they are technically a rhizome --- a swollen bulb-like root. Plant iris from early spring through midsummer. The later you plant, the less likely they will bloom in the current year.

Tender Summer-Flowering

Plant tender, summer-flowering bulbs such as gladiolus, canna, dahlia and tuberous begonia in mid- to late spring, after all danger of frost has past. In southern Wisconsin, plant in late April to early May and in northern Wisconsin, plant in late May to early June, depending on the average date of your last spring frost.

References

• University of Minnesota Extension: Bulbs, Rhizome, Corms and Tubers
• Wisconsin Regional Lily Society: Transplanting Lilies

Resources

• University of Wisconsin Extension: USDA Plant Hardiness Zone Map