Photograph by Bart Worthington, Mountain States Wholesale Nursery Chuparosa

WHAT TO PLANT

Cacti—Visit nurseries to find cacti, many of which are in bloom. If transplanting cacti from your landscape, orient them in the same direction as they were previously growing to avoid sunburn.
Vegetables—Sow cantaloupe, black-eyed peas and okra. Transplant Jerusalem artichoke and sweet potato.
Turf—Bermuda seed or sod can be planted all month long. Plant stolons after May 15 in the Phoenix area; wait until June 15 in the Tucson area.
Hummingbird gardens—Plant tubular or trumpet-shaped flowers in shades of red, orange and pink such as chuparosa, penstemon and salvia. Incorporate various penstemon species to bloom throughout the warm season, including Penstemon barbatus, P. eatonii, P. parryi, P. pseudospectabilis and P. superbus.

GARDEN MAINTENANCE

Apply mulch—Before summer heat, spread several inches of organic mulch (compost, grass clippings, leaves) around the bases of plants to reduce soil temperature and maintain moisture.
Adjust irrigation schedules—Water more frequently during hot weather, but for the same length of time. Water should soak 1 foot deep for shallow-rooted plants (annuals, perennials, ground covers, cacti, succulents), 2 feet deep for shrubs, and 3 feet deep for trees. Irrigate Bermuda grass to a depth of 8 to 10 inches every three to five days. Use a soil probe to determine how far water penetrates. The probe will move through moist soil but stop at dry, hard soil.
Ignore citrus fruit drop—Expect excess shedding of fruit this month, as citrus trees set more fruit than they can carry to maturity; therefore, no intervention is required.
Water deciduous fruit trees—Fruit is getting plumper this month. Apply water to a depth of 3 feet to provide sufficient moisture.
Maintain roses—Feed with a liquid fertilizer every two weeks during spring’s peak bloom period. Don’t worry about half-moon shapes cut from leaves and petals. Leafcutter bees remove these bits to line their nests. This does not harm plants, but if exhibiting roses in shows, protect shrubs with floating row cover.
Protect tomato plants—When temperatures stay above 90 degrees, cover with 50-percent shade cloth.
Harvest garlic and winter onions—They are ready to dig up when leaves turn brown and become limp.