Tidy up your planting beds

Finish cutting back perennials and cleaning up garden debris early this month if you have not finished this job yet. It is best to cut back perennials before they start growing to minimize damage to new growth.

Be careful not to damage any new growth that is likely to have begun by this time of year. New sprouts can also be easily damaged by vigorous raking. A leaf blower works well to clear debris out of beds. I generally leave some of the tree leaves from last fall in my beds, as I prefer a more natural look, and like to save time instead of doing a detailed cleanup.

It can be hard to see new growth on ornamental grasses, so cut them back before consistent warm weather sets in later in the month. If the weather warms up and the grasses are growing, cut them at a few inches above the ground to avoid the new shoots. Be careful of any bulbs that have started growing. Try to avoid working in beds that are wet.

• It is time to begin spraying crabapples that are susceptible to apple scab (typically, this disease affects older varieties of crabs). If your tree's leaves become covered with black spots and fall off in late summer, it needs a protective spray program or should be replaced with a new, disease-resistant cultivar. Begin spraying after the buds open and treat once every seven to ten days until the leaves are fully open (generally, three treatments suffice).

The ideal date to start these treatments can vary from year to year, as it depends on the tree's stage of growth, which is linked to the weather. Call or email the Chicago Botanic Garden's Plant Information Service at (847) 835-0972 for recommended fungicides and timing for applications.

• Continue to protect tulips from deer and rabbit damage by spraying with a repellent or covering with netting. Repellents need to be reapplied after a moderate rain. Netting needs to be adjusted as bulbs grow and may need to be weighted down to keep it from blowing away.

Deer and rabbits generally do not eat daffodils, Siberian squill or ornamental onions. It is important to keep protecting your tulips until after they have flowered.

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