Continue harvesting citrus, including late navel, sweet, pigmented, and valencia oranges; grapefruit; tangelos; lemons; and limes. The longer fruit stays on the tree, the sweeter it becomes, but some varieties are nearing the end of their productive season, so don't let them go to waste.
Examine Saguaro Cacti for Rot
Look for oozing, black, smelly areas that indicate bacterial necrosis. If found, treat immediately or it can kill the cactus. Use a sterile, sharp knife to cut out all of the rot. Healthy tissue will be light and firm, resembling a raw potato. Dispose of the rot in the garbage. Rinse out the wound with a solution of 1 part bleach to 9 parts water. Let the area dry and callus over naturally.
Water Deciduous Fruit Trees
These trees need consistent soil moisture to size up fruit during April and May. Water should penetrate 3 feet deep and be applied at the edge of the foliage canopy where feeder roots absorb water and nutrients. Move emitters or bubblers outward as the tree grows.
Plant Annual Flowers
Sow seeds or set out transplants for warm-season annuals including coreopsis, cosmos, dianthus, impatiens, lisianthus, marigolds, purslane, salvia, sunflowers, Mexican sunflowers, and zinnias. Plant in improved soil and keep consistently moist until seeds germinate.
Feed and Water Roses
Water bushes to a depth of 2 feet. Use a soil probe to determine how far water soaks. The probe will move easily through moist soil and stop at dry, hard soil. Feed with a rose or flowering plant fertilizer. If you prefer organic fertilizers, use a nitrogen and phosphorus source such as blood meal and bonemeal. Follow package instructions for application rates.