Protect your spring garden: Tips for bulbs, perennials and roses

If you kept a coleus from the garden last year as a houseplant, you can still start cuttings for transplanting outdoors. I have a coleus on a windowsill in my office at the Garden.

Use a sharp, clean knife or a pair of pruners to cut the stem just below a leaf node. Remove the lowest leaves, dip the cut end into a rooting hormone and insert it into some fresh, sterile potting soil. The cuttings will also readily root by placing them in a glass of water. Transplant to a pot with growing medium once a small mass of roots has developed.

The plants will be ready to use in the garden by the middle of May when the danger of frost has passed. Gradually acclimate coleus plants to the outside environment by increasing the time the plants are left outside over a period of a week or so. Be sure to avoid direct sun at first so the leaves do not burn.

Protect emerging tulips from deer and rabbit damage by spraying with a repellent or covering with netting. If local populations are high, these animals can be very aggressive in spring as they look for plants to eat. Repellents must be reapplied after rain. Netting should be adjusted as bulbs grow and may need to be weighted down to keep from blowing away. Animals do not typically eat daffodils, hyacinths or ornamental onions.

Finish cutting back perennials and cleaning up garden debris in the next couple of weeks. It is best to cut perennials back before they start growing to minimize any possible damage to the new growth. I like to cut stems off at 4 to 6 inches above the soil and leave some perennial foliage in the beds.

There is a planting of hostas under one of my mature oak trees that I do not clean up in spring. I let the hosta grow through the old foliage and a light layer of leaves. It can be hard to see new growth on ornamental grasses, so be sure to cut them back before consistent warm weather sets in. If the weather warms up and the grasses are growing, cut them at a few inches above the ground to avoid the new growth.

Many perennials are sprouting now in our area. Be careful of any bulbs that have started growing. Avoid or minimize walking on ground that is wet from melting snow, spring rainstorms or as the frost is coming out. The soil generally takes longer to dry out during the cooler spring temperatures than it does in summer.

Begin uncovering hybrid roses in early April by carefully removing mulch from the base. A bamboo stake works well for this task. Leave a small amount of mulch at the base for protection in case of a late hard freeze. Monitor the weather forecast and adjust your timing as needed if extended cold periods are predicted. Prune these roses back to live growth, which in some years may leave only 1 to 2 inches of stem.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.