After the recent rains in much of the southwestern desert, weed seeds have been germinating with great enthusiasm. To keep them at bay, pull weeds as soon as they rear their ugly heads. Don't let them flower and go to seed, as they will create a zillion seeds. Weeds can also harbor pest insects, so rid your garden of them at the same time.
Prune roses, deciduous fruit trees, grapes, non-native deciduous shade trees, and shrubs. Wait until warmer weather to prune frost-sensitive tropicals such as bougainvillea, hibiscus, and lantana. Use sharp tools and disinfect them between plants to help prevent the spread of disease. Use a solution of 1 part bleach to 9 parts water as a disinfectant.
Control Cabbage Loopers
Check for cabbage loopers on cool-season vegetable crops such as cabbage, broccoli, cauliflower, and kale. These small caterpillars are about an inch long, pale green, and are often found underneath leaves. They form little loops with their bodies as they move, thus their name. Hand picking them off the plants is the easiest method of control.
Fertilize Container Plants
Fertilize containers of cool-season annual flowers and vegetables. They quickly use up the soil's nutrients and need to be replenished regularly with a balanced fertilizer. If plants are specifically showing signs of nitrogen deficiency (older leaves are yellowing, but new growth is green), apply a nitrogen source, such as fish emulsion. Fertilize container plants every 2 weeks during while they're actively growing.
It's time to give citrus trees one third of their total annual nitrogen requirement for the growing season. The amount to apply varies, depending on the tree's size and on how long it's been planted. A citrus tree that's been in the ground for 6 years is considered mature and needs about 1 1/2 pounds of actual nitrogen per year. Spread fertilizer outside the tree's drip line, where "feeder" roots are actively growing.