By Richard Jauron, Greg Wallace
While mild winter weather is a pleasant surprise, it can have negative effects on plants that bloom ahead of schedule. Here are some tips from Iowa State University Extension and Outreach horticulturists on the proper way to care for spring-flowering bulbs in winter. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or hortline@iastate.edu.
It’s only February, but my tulips are coming up. What should I do?
Tulips, daffodils and other spring-flowering bulbs normally begin emerging from the ground in March or early April in Iowa. However, mild winter weather can encourage premature growth. The early emergence of spring-flowering bulb foliage is most often seen on the south and west sides of homes and other buildings. These areas usually are warmer than the rest of the yard because sunlight is reflected off the building to the ground. In addition, heated basements keep the soil near homes relatively warm.
While the premature emergence of spring-flowering bulb foliage is undesirable, the danger is not as great as it may seem. The foliage of tulips, daffodils and other spring bulbs can tolerate cold temperatures. Oftentimes, normal winter weather (cold temperatures and snow) returns, delaying further growth. A blanket of snow is especially helpful. The snow discourages additional growth and also protects the foliage from extreme cold.
I purchased some tulip bulbs last fall, but didn’t get them planted. Can I plant them outdoors in spring?
Tulips, daffodils and other spring-flowering bulbs must be planted in fall. Fall planting allows the bulbs to develop a root system before the ground freezes. Fall planting also exposes the bulbs to cold temperatures in winter. Exposure to cold temperatures is required for the bulbs to bloom in spring.
Tulips and other spring-flowering bulbs do not store well over long periods. The viability of unplanted bulbs gradually declines over the winter months. Unfortunately, it’s probably best to discard the tulip bulbs as they are likely severely weakened and unable to flower or dead.
Is it possible to save tulip bulbs that have been forced indoors?
Tulips, hyacinths and most other spring-flowering bulbs that have been forced indoors are usually discarded after flowering. Most won’t bloom again when planted outdoors. Daffodils are an exception. Daffodils are more vigorous than tulips and most other spring-flowering bulbs. Forced daffodils can be saved and successfully planted outdoors.
The care after flowering is important if attempting to save forced bulbs. After blooming, remove the spent flowers and place the plants in a sunny window. Water regularly until the foliage turns brown and dies. Carefully remove the bulbs from the potting soil, allow them to dry for one to two weeks, then store the bulbs in a cool, dry location. Plant the bulbs in fall.