Ask A Master Gardener – Plan Now for Spring Blooms

Every gardener knows that the best tool they have for a successful garden is a good plan. Waiting until the last minute to execute an elaborate scheme is a recipe for failure.  Now is the time to add to or develop that plan for a beautiful array of spring blooms.

Spring flowering bulbs must be planted in the fall in order to have those glorious blooms appear on cue. In Wisconsin, planting begins in mid-September and can continue until the ground nears freezing.  Planting earlier ensures that the bulb will have time to develop a good root system and will have a better chance of survival.

The first step in planting is to know your bulbs. The term “bulb” includes true bulbs, corms, rhizomes, and tubers.  All of these structures are food storage vessels that provide nourishment for the plant during the growing and dormant season.

True bulbs (tulips, daffodils), house complete plants within the bulb. Corms (crocus, gladiolus) are a type of compressed stem filled with food storage tissue. They form little babies that can be separated to make new plants.  Rhizomes (iris) are underground stems that grow just below the soil surface.  Growth buds from along them to produce the next year’s flowers.  Tubers (dahlias, potatoes) are underground roots with “eyes” that are buds.  Most people use the term “bulb” to refer to all of the different structures and do not differentiate between them.

Another bulb fact to keep in mind is the difference between hardy and tender bulbs. Tender bulbs include dahlias, begonias (Begonia tuberosa), cannas, and gladiolus.  These are planted in the spring for summer blooms, but must be dug again in the fall as they cannot withstand winter temperatures. Alternatively, they can be planted as annuals and allowed to die each year.

Hardy bulbs are typically planted in the fall and require a cold period to break dormancy and begin the flowering cycle. Tulips, daffodils, hyacinth, and crocus all fall into this category and are the ones to be planted this time of year.  Once planted, they need not be dug up until it comes time to divide them.  In fact, once properly planted, they will require minimal care but will provide a consistent dazzling array of color in the spring.

Purchase bulbs from a reliable source, making sure none are soft, moldy, diseased, or damaged. Choose a location with good drainage and ample sun.  Remember that these plants will often flower before most trees are leafed out, so you might be able to plant in locations that will be too shady later in the season.  Prepare the bed by working organic matter or compost into the top twelve inches of soil.

Plant bulbs with the pointed end up, root end down, at a depth 2-3 times the diameter of the bulb. Bulb flowers are more eye-appealing if planting in masses or odd numbered groupings rather than straight lines.  Once the bulbs are located, cover them with soil and water thoroughly to settle the soil and provide the necessary moisture for good root growth. Cover the bed with several inches of good organic mulch to help stabilize the temperature and keep the soil moist.

In the spring, remove spent flowers, but leave the foliage until it dies back. Both practices will ensure good bulb health for future years.


Carol Shirk

Certified Master Gardener


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