Fall will be here before you know it – the beginning of the end to the growing season. And an excellent time to plan for next spring. Part of that planning may involve bulbs.
While “bulb” is used very broadly to describe certain perennials that die back to underground storage after flowering, some spring-blooming perennials are technically not bulbs but rather corms or rhizomes.
A true bulb has the embryo of a new plant buried deep inside, protecting layers or scales, which serve as food reserves for the tiny bud. The stem of the plant is compressed into the basal plate, which can branch and form new bulbs, called offsets. Narcissus, hyacinth, tulip and Dutch iris are all true bulbs (as are onion and garlic).
Corms are similar to bulbs but do not have the fleshy scales. Corms can be round or slightly flattened at the top. Buds sit at the top of a corm and roots are on the underside. The parent corm produces cormels (or cormlets) from buds on its top or side. Crocus grows from a corm (as does gladiolus).
A rhizome is quite distinguishable from the others because it grows horizontally through the soil and generally has a thickened stem used for storage. Both bearded and beardless iris grow from rhizomes (as do calla and canna).
In eastern Nebraska, spring-blooming bulbs, corms and rhizomes can be planted from late September through the end of October. Ideally, the soil temperature will be below 60 degrees at planting time.
Sun is a must; most require at least six hours of sunlight. However, many of these plants will bloom before the trees leaf out, so they could be installed in areas that become shadier in summer. I do find, though, the most reliable bloomers are those in full sun year-round.
It is recommended to mix bone meal into soil at the bottom of the planting hole; however, as a dog owner, I dispense with that part when planted in an area frequented by canines.
For a natural look, plant in clumps, not straight lines. And plan for a post-bloom summer by placing bulbs behind other perennials or where there will be annuals to hide bulb foliage as it dies back after blooming.
Irrigation is necessary after planting to ensure proper root development. Water after installation and every couple of weeks until the soil freezes. Wood chip mulch should be layered on top (about 3 inches deep) to conserve moisture and regulate soil temperature.
It might not be top of mind to plant something new right now, but you’ll be glad you did when those first colorful blooms appear in the garden after a long winter.
Since 2004, Mari Lane Gewecke has been a Master Gardener volunteer, affiliated with the University of Nebraska-Lincoln campus program. She is also a self-employed planning consultant.