Northern & Central Midwest
Watch for Diseases on Roses
As you prune your roses, look for diseases problems on live canes. Check for purple or black spots as well as blister-like areas. Prune these canes out completely and destroy them. This will go a long way to preventing fungal infections on leaves and canes in the new season.
Don't Feed Lawns Too Much Nitrogen
Lawns do not need much additional nitrogen in spring to encourage growth. Too much can deplete carbohydrate reserves and make the grass need more moisture and more frequent mowing, and make it more attractive to insects and disease. If you must fertilize, do it lightly and have a soil test done first to determine what to add.
Watch for Pests!
It may seem early, but be on the lookout for pest problems. Catching them early will go a long way toward preventing population explosions. Get out into the garden daily, starting now, and anything that just doesn't look right should have a closer examination. Keep your horticultural oil, Bt, and insecticidal soap handy.
Pinch Garden Mums
If you grow garden mums, get ready for pinching. Pinching makes the plants stocky and attractive with plenty of blossoms. New shoots should be pinched regularly, usually once a month from May to July. Be sure to leave at least two or three leaves on each shoot. You can also fertilize the plants at the same time.
Harvest Rhubarb and Asparagus
Continue harvesting rhubarb and asparagus through the month of May. As soon as asparagus stalks become as narrow as a pencil, stop harvesting and let them go to foliage. Only harvest about half of the rhubarb stalks at any one time. When the new shoots become spindly, stop harvesting for the summer.