Southern California Coastal & Inland Valleys
Continue reseeding a flat of heat-tolerant leaf lettuce throughout the summer to have seedlings to transplant into unused spots as earlier crops are harvested.
Plant Tender Trees
The weather from now through June is ideal for planting citrus, avocados, and other tender trees such as kiwis, kumquats, and pomegranates. In frost-free areas, also try cherimoya, guava, mango, and passion fruit. For containers, be sure to choose dwarf types. For the best choice in citrus, look for trees with many strong branches, a smooth graft union, and deep green leaves.
Feed roses heavily to ready them for their long blooming season. Incorporate manure, bonemeal, and cottonseed meal within the plant dripline to the depth of three inches. Water deeply. Weekly or every other week until fall, prune the spent blooms down to the first five-part leaf or a bit further to gently shape the plant, feed lightly, and water. Repeating this process through the season will encourage continuous bloom throughout the season. Water only in the mornings or early afternoons so foliage dries out by sundown, to lessen mildew and other disease problems.
Prune Dead Wood
Prune frost-damaged wood once the plant or tree has completely leafed out and you can easily see just what wood is dead. If you're in doubt, wait another month to avoid pruning wood that was just late in leafing out. By mid-summer, any remaining deadwood will be obvious.
Check Irrigation Depth
To test how deeply your irrigation water is going, water for the usual length of time and then push a trowel into the soil its full length. Push the soil clump to one side, or lift it out completely, and look at both the depth of the roots and the water line in the soil -- it'll be dark toward the lawn surface and lighter where it's dry. The water line should be just past the longest roots. If it's not this far down, replace the clump, water again, and test another spot until the water line is below the roots. Adding all these irrigation times together gives you the correct amount for each watering. Don't water again until two-thirds of the root length is again dry. This may mean that you can double the time between waterings, and the grass roots will not suffer during the really hot portion of the summer.