AMES, Iowa – Winter 2017 has been unusually mild in Iowa, with daily high temperatures in the 50s and 60s and approaching record highs. This is good news for those who dislike snow and icy conditions, but it can confuse spring-flowering bulbs and lead to early growth.
Iowa State University Extension and Outreach horticulturists can help answer questions about premature-flowering spring bulbs. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
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 are usually 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. Often 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.
Unfortunately, rabbits are quite fond of tulips and will often eat the foliage right down to the ground in spring. The best way to stop rabbits from eating tulips is to place chicken wire or hardware cloth fencing around the plants as soon as foliage emerges from the ground.
Unplanted tulip and other spring-flowering bulbs oftentimes shrivel up and die over winter. Tulip bulbs that remain viable (alive) in spring usually don’t perform well when planted in spring. Tulips and other spring-flowering bulbs are planted in fall so the bulbs have adequate time to develop good root systems before winter. Additionally, spring-flowering bulbs must be exposed to cold temperatures in order to bloom. Spring planted tulips usually don’t grow well because they lack well developed root systems. Plus, they often fail to bloom. Regrettably, it’s usually best to discard unplanted tulip bulbs in spring. Buy and plant additional bulbs in fall.
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 begins to yellow. At this point, gradually cut back on watering until the foliage withers 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.