In the low desert, fertilize bushes every six weeks to help them gear up for major spring bloom in April. A local consulting rosarian prefers fertilizer that contains chicken manure for his roses. At higher elevations, plant bare-root roses and prune established roses, removing dead, weak and crossing canes. Wait until new growth starts and weather warms to apply fertilizer.
Control Late-Germinating Weeds
Recent late winter rain showers will germinate a crop of weeds. It's easy to remove them when they are small and soil is still somewhat moist. Let the pulled weeds remain on the ground to decompose and add nitrogen and organic matter back to the soil, or toss them into your compost pile (as long as no seeds are attached). Don't let weeds go to seed. Their seeds can remain dormant in the soil for years until conditions are just right for germination.
Rejuvenate Container Plants
Frequent watering leaches away nutrients in containers and roots can't spread out into the soil to seek more. Use a slow-release fertilizer or feed every 2 weeks with a balanced fertilizer (such as 5-5-5 or 10-10-10) to replenish nutrients. Nitrogen deficiency is the most common problem with annual vegetables. Symptoms are older leaves (lower on the stems and branches) turning yellow while new growth (higher on the stems and branches) remains green. Fish emulsion is a good organic source of nitrogen.
Sow basil indoors for transplanting outside when temperatures warm. Use a sterile potting soil to prevent damping off disease, which causes seedlings to tip over and die very quickly. Basil varieties offer different tastes to experiment with in the kitchen. 'Italian' or 'Genovese' are traditional for tomato and pesto sauces. Also try cinnamon, lime, or lemon basils. If you like Thai food, plant 'Siam Queen' Thai basil, a pretty herb with purple flowers and stems and bright green leaves. Purple leaf basils such as 'Dark Opal' and 'Purple Ruffles' give you the option to create colorful plant contrasts with green basils. 'African Blue' is fairly cold tolerant basil that may live through the winter.
Monitor for Powdery Mildew
With late rains and relatively cool temperatures, powdery mildew fungal disease may rear its ugly head. If humidity increases, it is more likely. Powdery mildew describes itself: a white powder is dusted across foliage and along stems. It strikes plants that are crowded without good air circulation. Once powdery mildew establishes itself in the garden it's difficult to eradicate, so be vigilant. Remove any leaves (or entire plants if it has affected annual flowers or vegetables) and discard in the trash, not the compost pile. Clean up any mulch around the plants and discard it. Disinfect tools immediately with a solution of 10 percent bleach and 90 percent water so you don't spread it to other plants. Prevent powdery mildew by thinning plants to allow the recommended spacing as they reach maturity. As a last resort, dust plants with sulfur when temperatures are under 90F. Follow package instructions exactly.