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April/May 2021 Garden Checklist

What to Plant: Low Elevations


Transplant eggplant and peppers now to harvest in summer. ‘Kermit’ is a branching, Thai eggplant that produces 2-inch round, green fruits. If you prefer a traditional, purple type, try ‘Hansel,’ a compact variety that yields fruits that are 4 inches long and about 1 inch wide. Spice up your summer curries with ‘Bangkok,’ a small but powerful pepper, or ‘Roulette,’ a habanero that packs all of the flavor without any of the heat. Sow seeds of summer-loving yardlong beans, such as ‘Red Noodle’ and ‘Asparagus Yardlong,’ which can be trained to grow up a trellis to save space in smaller gardens.


Radishes are among the most forgiving vegetables you can grow. Unless you plant them too deep (more than 3 inches) or forget to water them, these root vegetables are practically guaranteed to produce all year long. ‘Sora’ and ‘Rover’ are classic, red and round varieties that are noted for their heat tolerance.


There is always room for a few new cacti in a desert landscape. Cactus breeders have hybridized varieties of Echinopsis, or hedgehog cacti, to bloom in just about every color of the rainbow. For compact plants that produce proportionally enormous blooms, look for ‘Lemon Pie’ if yellow flowers fit your palette or ‘Sorceress’ if you prefer magenta. Plant in part-shade (2-4 hours of direct sunlight each day), and protect fresh plantings from sunburn by covering with a shade cloth for the first summer.

What to Plant: Middle and High Elevations


Sow seeds of broccoli, leeks, snap peas and leafy greens such as chard, kale, spinach and leaf lettuce. Give each broccoli plant a 2-by-2-foot area to allow room for branching. Train snap peas to climb a trellis to make it easier to find and harvest the sweet pods as they appear. Lightly and gently irrigate with a soaker hose or sprinkler every day until seeds germinate. Once seedlings emerge, gradually increase the amount of water applied and extend the length of time in between irrigations. Ideally, you will only need to water every 3-4 days during the summer if there is ample moisture stored in the soil.

Protect new plantings, by seed and transplant, from insects and birds with floating row covers, which are lightweight lengths of fabric designed to allow sunlight in but exclude hungry pests. For crops that require pollination, such as melons, peppers and eggplant, remove the covers when plants begin to bloom. Leave them on crops that are grown for their leaves or roots, such as lettuce and radish.


Herb gardens can be easily grown in containers. Be sure to select pots with drainage and use fresh potting mix that is free from weed seeds or other pests. Transplant cilantro, parsley, oregano, thyme, marjoram, dill, lemongrass and catnip. At higher elevations, start seeds indoors now to set out in June.


Colorful choices for Arizona’s middle and high elevations include daylily, coral bells, hosta, bearded iris, false indigo and moss phlox, among many others. Perennials bloom throughout the summer and go dormant during winter, only to return in the spring and repeat the process year after year. Plant them in a hole the depth of the root ball and at least twice as wide.

Garden Maintenance: Low Elevations


After the center crown of broccoli has been harvested, watch for smaller heads forming on side branches and pick those before the buds start to open and show yellow. Check seed envelopes from root vegetables you planted earlier to determine their size at maturity and harvest, as appropriate. If left in the soil for too long, particularly in hot weather, these crops can become woody or take on undesirable flavors.


The days are getting longer and hotter, so water more frequently to help plants avoid drought stress. Turf, vegetable and flower beds may need to be irrigated every 3-4 days; non-native trees and shrubs, such as citrus and roses, every 7-10 days and native plants every 14-21 days. Add irrigation emitters as plants grow—wetting patterns for trickle irrigation should overlap all around the drip line of the plant to ensure the entire root ball is being watered.

Garden Maintenance: Middle and High Elevations


Remove limbs that are dead or damaged with the appropriate sharp, clean tool. Small stems less than 0.5 inches in diameter can be removed with handheld pruning shears. Limbs between 0.5 feet and 1.5 inches in diameter should be cut with bypass loppers—the long handle gives better leverage for slightly thicker stems. For limbs thicker than 1.5 inches, use a pruning saw or hire a pro. Cuts should be made where the branch attaches to the main stem. Never leave a stub and be careful not to allow bark to peel when dropping heavier limbs. Learn how to make good pruning cuts by checking out this publication from the International Society for Arboriculture: “Pruning Mature Trees” at

AUTHOR’S NOTE: The Valley garden community lost an important leader, advocate and friend on December 18, 2020. Terry H. Mikel was a retired horticulture extension agent from the University of Arizona and taught thousands of people, including me, to garden. Much of what I write in Phoenix Home & Garden is taken from Terry’s teachings.
—Kelly Murray Young


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