May to-do list for gardeners

By Rebecca Jepsen
For the Mercury News
May 1, 2010

Mulch around trees and shrubs to retain moisture, provide nutrients and deter weeds. Apply a 2- to 3-inch layer of organic matter or chipped tree trimmings; keep it several inches away from the trunks of the plant to prevent rot.

Control earwigs that can cause significant damage to soft plants. They feed at night and hide in moist, tight spaces during the day. Trap them by setting out a moistened, tightly rolled newspaper at night and then discarding it in the morning.

Prune for fire blight. Spring is when you often see the effects of this bacterial disease when it is spread by insects, rain and pruning. Fire blight can blacken branches and twigs of apple, crabapple, hawthorn, loquat, pear and toyon trees. If left unattended, it can kill the tree. Prune the infected branch about 8 to 12 inches below visible damage. Sanitize tools between cuts.

Attack powdery mildew, a disease that produces a white powder on leaves of roses, dahlias, peas and squash. A homemade spray can be effective. Add 4 teaspoons of baking soda to a gallon of water, mix in 2½ teaspoons of light horticulture oil (or salad oil), and spray affected plants.

Prevent rust on snapdragons, sunflowers, sweet peas and pansies by avoiding overhead watering and removing affected plant parts as soon as they appear. Rusts are easily identified by the dry brown, orange or yellowish spores that form on lower leaf surfaces. Fungicides such as neem oil can be applied at the first signs of infection.

For our complete list of May Gardening Tips, click on: www.mastergardeners.org/tips/may.html.

What to plant now

Transplants: arugula, basil, beans, beets, chard, cucumbers, eggplant, lettuce, melons, peppers, squash, tomatoes.

Seeds: arugula, basil, beans, beets, chard, corn, cucumbers, melons, peppers, squash, tomatoes.