As many perennial plants are getting ready to go dormant for the winter, it is time to start thinking about next spring’s floral display and plant spring-flowering bulbs. The best time to plant spring bulbs is late September through October to allow sufficient time for a good root system to develop before winter. Depending on the location, spring bulbs begin blooming in late February (snowdrops) and continue until late June (alliums).
When purchasing bulbs, keep in mind that larger bulbs will produce larger blooms. Bulbs should be firm and free of rotting spots or signs of disease.
For the greatest visual impact, plant bulbs in groupings, and large drifts or waves of color in areas that received at least 8 hours of sunlight daily. Mix them in with other perennials and shrubs to screen the foliage after blooms fade.
The general rule of thumb when planting is to bury them two to three times deeper than the length of the bulb, measured top to bottom. Bulbs should be spaced six to 12 inches apart to allow for spreading and future divisions. Plant them with the nose of the bulb (pointy side) facing upward, and the root plate (flatter side) facing downward.
After covering the planted bulbs with soil, water the area well to settle the bulbs into the soil and initiate root development. If there is little rain in the fall, continue to water weekly until the ground freezes. Add a light, 2-inch layer of mulch to the soil after planting to minimize temperature fluctuations in the winter and to help converse moisture in the soil.
To prevent pesky squirrels and chipmunks from digging up your bulbs, cover the area with chicken wire or hardwire mesh after planting, and mulch over the top. Avoid using natural fertilizers (like fish emulsion or bone meal) that may attract the animals.
Try layering your bulbs in a container for something new. Layer the bulbs like lasagna- the largest bulbs are placed in the bottom of the container (with a drainage hole), add two inches of potting soil on top of the bulbs, and then plant the next sized bulbs. Continue with three to four layers to create a dramatic and colorful arrangement next spring. Use the container of soil and bulbs as a base for an evergreen arrangement on your porch in the winter.
For more information about spring bulb selection, planting, and care, view my colleague Martha Smith's video or visit the University of Illinois Extension Bulbs & More website.