Spring-flowering bulbs get the gardening season off to an early start. From snowdrops and crocuses to daffodils, tulips, and alliums, they provide months of easy color. Once spring bulbs have finished blooming, gardeners often wonder what to do about the fading flowers and foliage. This depends on whether you are treating the bulbs as annuals or as perennials.
Spring Bulbs as Annuals
Though most spring bulbs are hardy perennials that bloom year after year, many people plant fresh bulbs each fall. If you are planning to replant, simply use a garden fork to “lift” the spent plants (bulb and all) and add them to your compost pile. Potted bulbs can also be discarded. Part of the fun of spring bulbs is being able to plant something new each year!
Spring Bulbs as Perennials
Early bulbs such as snowdrops, crocus, chionodoxa, and scilla are hardy perennials that will bloom again and also multiply over time. That’s true for most daffodils and alliums as well. Hyacinths will usually bloom for two or even three years, though the size of the flowers will gradually decline.
Tulips are less predictable. Whether they rebloom or not depends on the growing conditions in your yard and the species or even the variety of tulip you plant.
When tulip bulbs get large enough to produce big flowers, they have a tendency to split. If you have ever dug up bulbs after they bloomed, you may have seen this yourself. Once a tulip bulb splits, it usually doesn't have the energy to produce a full-size blossom.
In Holland, commercial bulb growers are able to produce large tulip bulbs by growing them under very carefully controlled conditions. Sandy, well-drained soil is essential, as are warm, dry summers. If you can replicate these growing conditions, your tulips may behave like perennials.
Some types of tulips are also less prone to splitting and more likely to perennialize. These include most species tulips, Darwin hybrids, emperor tulips and some triumph tulips.
Removing Spent Flowers
If you want your tulips, daffodils, hyacinths, and alliums to bloom again, it's best to snip off the flowers as soon as they fade. Your garden will look neater and you'll be encouraging more energy to go back into the bulbs. Smaller bulbs, including crocus, muscari, scilla and snowdrops, multiply by seed as well as by bulb offsets, so it's best to leave their flowers attached and let them ripen their seeds.
Removing or Hiding the Foliage
Bulbs use their foliage to produce energy for next year’s flowers. If you want your bulbs to rebloom, it’s important to leave the foliage in place until it has withered and turned yellow. This may take a few weeks or a few months, depending on the weather and the type of bulb. When the foliage is totally limp and it pulls away from the bulb with a gentle tug, it’s ready to go.