With cooler temperatures on the horizon, some gardeners may be ready for a well-deserved break in landscape activity. However, fall is the best time to plant those spring flowering bulbs. In Oklahoma, late September through the middle of November is the best time to get those bulbs in the ground.
Mailboxes of gardening enthusiasts probably are filling up with catalogs from various seed and bulb companies. To get the best quality bulbs, order early or visit the local garden center soon for the best selections. Ordering from a catalog likely will offer a wider variety of cultivars and species from which to choose. When shopping at the local garden store, remember the larger bulb usually means a healthy, vigorous plant.
There are some planting guidelines to follow in order to get the best results from the bulbs. First, plant generously. It’s better to plant tulip bulbs in groups of 20 or more, spaced about a foot apart, than to plant them in tight clumps. You'll get more bang for your buck. Daffodils provide a fantastic display when organized in swaths, sort of like a lazy river.
Something else to consider for visual interest is planting the bulbs in a scattered design. Don’t plant them in a straight row.
If you want a longer display of blooms, mix different species of blooming bulbs. Some species, like tulips, have early, mid- and late-season blooming varieties. Planting several varieties together will enable gardeners to extend the blooming time over several weeks.
When choosing a planting site, select an area with good drainage. Bulbs don’t fare well in soggy conditions, which can be common in Oklahoma’s clay soils. The site also needs to be in an area with at least six hours of direct sunlight each day.
Be sure not to plant the bulbs too deep, even tulips. Bulbs should be planted no more than two to three times the diameter of the bulb. So, if a bulb is 1 inch in diameter, it should be planted at a depth of 2 to 3 inches.
In some parts of the country, tulip and hyacinth bulbs will last for years. Unfortunately, Oklahoma summers and heavy clay soils can be stressful for most tulip and hyacinth varieties. It’s best to treat them like an annual and expect to replant again next fall. However, daffodils, crocuses, grape hyacinths and others tend to naturalize or multiply year after year. If you notice old clumps declining, go ahead and divide them. Keep the largest, healthiest bulbs and discard any small, weak or damaged bulbs.
In addition to spring-flowering bulbs, don’t forget pansies can be planted now along with ornamental cabbage and kale, and other cool season flowers. The pansies will be quite happy through most of the winter and come spring, by the time the bulbs are popping through the ground, they will begin to delight you with a colorful display.
David Hillock is a consumer horticulturalist with Oklahoma State University Cooperative Extension.