In Illinois, we plant hardy spring-flowering bulbs like tulips and daffodils in the month of October. For the most part, these can be easy ways for gardeners to add color, and non-gardeners to be successful in growing flowers because they really need little care aside from a few tips.
Even though most bulbs thrive in full sun, it is a myth that you cannot grow spring-flowering bulbs in the yard’s shady areas. Grape hyacinth, crocus, winter aconite, snow drops and Siberian squill can all be grown under deciduous trees and shrubs. Most of these bulbs make their appearance in the garden before leaves of deciduous trees begin to emerge. Snowdrops and Siberian squill can even grow in the shade of evergreens.
Trees that flower early are trees that leaf out early, like maple, redbud, cherry and magnolia. Early flowering shrubs include forsythia, flowering quince, Korean spice viburnum, and fothergilla. You may have less success growing under these species. Most other trees and shrubs would be free game for pretty much any bulb requiring sun.
Don’t plant bulbs in soil that is too wet or is poorly drained. Avoid downspouts and locations where snow is mounded during the winter months. If you live in Illinois, clay soil may be an issue for drainage. You know you have clay if you dig it up and it is smooth and sticky and can roll your soil into a shiny little ball. If you know you have clay soil, start with bulbs that are more forgiving, like grape hyacinth, daffodil, crocus, snow drops and camassia, and amend your heavy clay soil with compost.
A general rule of thumb is to plant bulbs two to three times as deep as the bulb is tall. It was once believed that tulips should be planted six to eight inches deep. However, Cornell University found that tulip bulbs planted more than six inches deep have fewer flowers, and now suggest tulips only be planted two to four inches deep.
Another myth you may hear is that adding phosphorous (usually in the form of bone meal) promotes root growth and provides more flowers. The relationship between the bulb’s roots and the fungi in the soil is more efficient at extracting phosphorous from the soil than from the added bone meal. Adding bone meal when planting actually interferes with this root-fungi relationship.
In general, bigger bulbs are better than smaller ones. Masses of spring flowering bulbs, planted two to five inches apart, are always more impressive than a few stragglers.
A bulb planter doesn’t make planting bulbs easier — a garden trowel will do.
Plant tips of the bulbs so they are pointing up.
Follow these few rules and you are sure to have a colorful spring.
Kelly Allsup is the University of Illinois Extension horticulture educator in Livingston, McLean and Woodford counties.
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