Spring 2021 Garden Checklist
What to Plant: Low Elevations
Sow seeds of milkweed, bee balm, black-eyed Susan, coleus, coreopsis, desert marigold, blanket flower, dusty miller, English daisy, four o’clock, geranium, hollyhock, lisianthus, marigold, purslane and sunflower. Choose a site that gets full sun—at least 8 hours per day—and lightly water daily until seeds have germinated and two true leaves have emerged.
Transplant globe and Jerusalem artichokes, peppers, sweet potatoes and tomatoes. Both kinds of artichokes will grow into shrubs about 4-5 feet tall and wide, so be sure to give them enough space in the garden. Sweet potatoes double as a bright green ground cover, so enjoy their beauty all spring and summer. Carrots, sweet corn, cucumbers (English and Armenian), cantaloupe, watermelon, green onions, radishes and summer squash can be planted from seed. Cover new plantings with floating row covers (available at garden supply stores), which will keep whiteflies, birds and other pests from damaging them.
When asked about the best time of year to plant a tree, renowned garden expert Terry Mikel always says “Today!” Early spring is a good time to plant many trees in the low desert, including Afghan and Aleppo pines, citrus, fig, pomegranate, eucalyptus, mesquite, palo verde, ironwood, Arizona rosewood and Southern live oak. Do not select trees with broken limbs or with roots that circle in the container, as these may be more likely to fail after transplant. Dig the planting hole at least twice as wide as the container, as this allows the roots to more easily colonize surrounding soil. But do not make the hole any deeper than the rootball. If planted too deeply, trees may become infected with bacteria that destroy the trunk. Only stake trees that are unable to stand on their own. For a thorough lesson on all things tree planting, download “Selecting, Planting and Staking Trees” at extension.arizona.edu.
What to Plant: Middle Elevations
Asparagus is a perennial, meaning you plant it once and harvest year after year. Transplant asparagus into permanent beds that receive 6-10 hours of direct sunlight each day. Dig the planting hole 6-8 inches deep and sprinkle blood meal or bone meal in the bottom to provide phosphorus for developing roots. Place 3-4 inches of mulch, such as pine needles or bark, on top of the soil to keep it insulated. Resist the urge to harvest shoots as they emerge; do your best to wait at least two years, as this gives the plant a chance to build up reserves to support repeated cuttings in the future.
Seeds of cabbage, beets, chard, endive, kale, leeks, lettuce, mustard, green onions, peas (snap and sugar) and spinach can be sown directly into outdoor beds. Start seeds of tomato, pepper and cucumbers indoors now to transplant outside in April. When starting seeds inside, use a sterile, specially blended seed-starting mix, which are free of plant disease-causing organisms and retain moisture but are also light enough to provide necessary oxygen for baby roots.
What to Plant: Middle and High Elevations
BAREROOT ROSES, VINES AND FRUIT TREES
Find bareroot plants online or at local nurseries. Remove the dormant plant from the packaging, discard the sawdust or packing material and soak the roots in a bucket of water while you dig the hole, which should be about 2-3 feet wide and 10 inches deep. Mound some soil in the center of the hole, pack it down firmly and arrange the roots over the mound to reduce air pockets as you backfill with the original dirt. Use a hose to trickle water in as you backfill to keep the roots moist during the process and settle the soil. Cover with a 3- to 4-inch layer of mulch to insulate and suppress weed emergence.
Garden Maintenance: Low and Middle Elevations
As days get longer and warmer, plants in the garden and landscape will require water more frequently. Use a soil probe to check below the surface and water trees, shrubs and perennials when the top 2 inches are dry. Water should penetrate to a depth of 1 foot for turf, flower and vegetable beds; 2 feet for shrubs and vines; and 3 feet for trees.
Remove any stems that were damaged by the winter cold. Cut woody stems back to the point of attachment to avoid unsightly stubs and cut ornamental grasses back to low mounds to stimulate fresh growth. Promptly irrigate freshly pruned plants to support new leaves and stems.
Garden Maintenance: High Elevations
MANAGE ACCUMULATED SNOW
Knock snow from tree limbs so the weight doesn’t cause them to snap. Mound snow around the plant’s dripline, which is the area on the ground just below the edge of the plant’s canopy. As the snow melts, the water will be available to the roots.