AMES, Iowa – When their tulips and daffodils no longer bloom, many gardeners wonder why. Iowa State University Extension and Outreach horticulturists offer guidance on what to do when these spring favorites fail to flower. To have additional questions answered, contact Hortline at 515-294-3108 or firstname.lastname@example.org.
Why are my tulips no longer blooming?
Most modern tulip cultivars bloom well for three to five years. Tulip bulbs decline in vigor rather quickly. Weak bulbs produce large, floppy leaves, but no flowers.
To maximize the number of years tulips are in bloom, choose planting sites that receive at least six hours of direct sun per day and have well-drained soils. Promptly remove spent flowers after the tulips are done blooming. Seedpod formation deprives the bulbs of much of the food manufactured by the plant’s foliage. Lastly, allow the tulip foliage to die back naturally before removing it. Tulips that don’t store adequate amounts of food in their bulbs are unable to flower.
Dig up tulips that are no longer blooming and discard the bulbs. (Small, weak tulip bulbs will likely never bloom again.) Plant new tulip bulbs in the fall.
While most modern tulip cultivars bloom well for three to five years, some tulip types (classes) bloom well over a longer period. Darwin hybrid tulips are generally the longest blooming hybrid tulip. Fosteriana tulips (also known as Emperor tulips) also bloom well for many years.
My daffodils produce foliage in spring, but no longer bloom. Why?
If the daffodils aren’t blooming, the plants weren’t able to store enough food in their bulbs in the previous year. Daffodil foliage typically persists for four to six weeks after blooming. During this time, the daffodil foliage is manufacturing food. Much of the food is transported down to the bulbs. In order to bloom, daffodils must store adequate levels of food in their bulbs.
Cutting off the foliage before it has died back naturally may prevent the plants from storing adequate food in the bulbs. Allow the daffodil foliage to die completely before removing it.
Plants in partial shade in May and June may not be able to store enough food in their bulbs because of insufficient sunlight. Dig up daffodils growing in partial shade when the foliage has died back and plant the bulbs in a location that receives at least six hours of direct sun per day.
Large clumps of daffodils may cease flowering because of overcrowding. Large daffodil clumps can be dug after the foliage has died. Separate the bulbs and replant immediately. Bulbs also can be dried for several days, placed in mesh bags, stored in a cool, dry location, and then planted in fall. It is possible to get weak (non-blooming) daffodils to flower again when given good care and favorable growing conditions.
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