Northern California Coastal & Inland Valleys
If you absolutely, positively can't wait another minute before you plant something in the earth, perennial blooming plants such as artemisia, coreopsis, gaillardia, penstemon, salvia, and wallflowers can be set out now. If you wait a bit longer, these same plants will be available in 4-inch pots at a dramatic savings.
Plant Summer Annuals From Seed
Celosia, cosmos, impatiens, marigolds, and petunias will be ready to plant in the warm spring soil in May if you plant from seed now. The longer days will get your seeds off to a good start. Set the seed trays in a warm, sunny spot. Cover with glass or clear plastic to hold in heat and moisture. Use a mist bottle to water the seedlings to avoid washing the seeds around the surface of the potting soil.
Patrol for Aphids
Look for infestations of aphids on new growth of roses. If you find large colonies, wash the foliage with a strong jet of water or purchase ladybugs from your garden center and release in the evening hours after watering the garden well.
Watch for Signs of Powdery Mildew
Powdery mildew will appear as the weather begins to warm. Look for white, powdery patches on upper sides of leaves. Treat with sulfur dust or make a fungicide of 1 tablespoon baking soda plus 1/2 teaspoon oil mixed in a spray bottle with 1 quart warm water. Apply frequently to control fungus disease.
Harvest Sweet Peas
Glorious bouquets of heavenly scented flowers are the reason for growing these early spring annuals. Sweet peas benefit from a weekly gathering of blossoms. The more flowers you cut, the more the plant will produce. As a matter of fact, the common name in Holland is "Cut & Cut Again." Once the plant is allowed to go to seed, flower production will cease. Cut the flowers at the base of the stems near the vine.