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March Garden Checklist

Learn what to plant this month, get maintenance advice and troubleshoot your gardening challenges with an expert.

By Kelly Young

What to Plant


Low Elevations

COOL-SEASON VEGETABLES–March is the last month you can sow seeds of beets, carrots, bok choy, green onions, leaf lettuce, spinach and radishes before the weather gets too hot and the days become too long. Select early seed varieties that will be ready for harvest in fewer than two months; afterwards, summer temperatures are likely to kill sensitive crops. Try ‘Cherokee,’ a heat-tolerant red-leaf lettuce, and ‘Win Win,’ a compact bok choy that is ready to harvest 54 days after planting.

WARM-SEASON VEGETABLES–Transplant or sow seeds of pumpkin, cucumber, squash, melons, bush beans and okra. Protect against whiteflies, which stunt development by sucking the juices from new growth, by covering seedlings with floating row covers, which are available at garden centers. Transplant tomatoes before midmonth to ensure pollination before temperatures climb to higher than 90 degrees.

TREES, SHRUBS AND WOODY VINES–For a shade tree that can reach 50 feet in height, try Chinese pistache (Pistacia chinensis), which also gives a glorious blast of fall color. Yellow butterfly bush (Buddleja davidii) is a must-have shrub for gardeners who want to attract pollinators to their yard. And if you are looking for a flowering vine with intoxicatingly fragrant blooms, plant Arabian jasmine (Jasminum sambac). Find interesting species suited to your landscape and get expert gardening advice at Desert Botanical Garden’s spring plant sale, which will be held on March 21-22. To learn more, visit dbg.org/events/spring-plant-sale.

Middle Elevations

FLOWERS–Prepare flower beds by first removing any existing weeds. Mix a phosphorus fertilizer into the soil, which supports seasonlong blooming. When applying any commercial fertilizer, follow the directions on the product label. Sow seeds of black-eyed Susan, blanket flowers, dianthus, violets, pansies, larkspur and nasturtium. Plant gladiolus corms, which are specialized underground stems similar to bulbs, for summer color. Cover the corms with 2 to
3 inches of mulch to insulate the soil.

VEGETABLES–Sow seeds of endive, leaf lettuce, kale, spinach, arugula, mustard greens, radish, turnips, beets, leeks and carrots directly into garden soil. Transplant rhubarb, horseradish, asparagus and garlic. Start tomato seeds indoors for transplanting outdoors in six weeks.

High Elevations

VEGETABLES–Start lettuce, cabbage, mustard greens, bok choy, onions and celery indoors to be transplanted outdoors in May. Plant dormant asparagus crowns, garlic sets and rhubarb outdoors. Cover outdoor plantings with a 3-to-4-inch layer of mulch to insulate the soil.

Garden Maintenance


Low Elevations

DEADHEAD ROSES–Use clean, sharp garden snips to remove spent roses and stimulate fresh blooms.

FERTILIZE–Give citrus trees one third of their annual required nitrogen, which can range from 1.5 pounds of ammonium sulfate for small trees to 7 pounds for large ones. Feed annual ryegrass 5 pounds of ammonium sulfate per 1,000 square feet of lawn. Follow feeding applications with irrigation to move the fertilizer into the root zone.

PRUNE SHRUBS AND WOODY VINES–Shrubs and vines that were damaged by winter cold or have grown too large and leggy can be cut back now. Trim stems back to their point of attachment to avoid creating stubs, which are prone to invasion by insects and other pests.


Middle and High Elevations

IRRIGATE–Windy March days speed up water losses from the soil. Apply irrigation water to a depth of 1 foot for lawns, vegetable gardens and flower beds; to a depth of 2 feet for shrubs; and 3 feet for trees to prevent drought stress and promote healthy roots. Use a long, pointed and sturdy metal probe to determine how deeply applied water penetrates the soil. The probe will glide easily through moist soil and abruptly stop where it meets dry soil. Keep adding water until the desired depth is reached.

SUPPORT PLANTS COMING OUT OF DORMANCY–Give nonnative deciduous plants, such as lilac, forsythia and catalpa, a helping hand with some fertilizer and a drink of water as they come out of dormancy. Select a fertilizer that contains nitrogen, phosphorus, potassium and sulfur, and follow the instructions on the product label to determine the correct amount to apply. After fertilizing, apply water using the guidelines mentioned above.

Forsythia

Garden Solutions


A large Texas ebony grows near my driveway. I love the shade it casts by day, but dozens of large black birds roost in it at night and leave a terrible mess all over my car. I don’t want to remove the tree, but I’d like to be able to park in my driveway. Any suggestions?

Texas ebonies (Ebenopsis ebano) are prized for the deep, dark shade they provide. They are also known for their intolerance to severe pruning. Grackles are fairly large birds that tend to roost in noisy groups, returning to their favorite spot at dusk each night. Rather than modify the tree, I recommend discouraging the birds from returning to roost. Drape bird netting, available at

Illustration by Gary Hovland

most garden supply stores, over the canopy of the tree. You can also dissuade the birds by shooing them away with noise and movement. Each evening, as the birds begin to settle in, bang pots and pans and use a long pole to jostle the branches and send the signal to the birds that they are not welcome. Be consistent and patient; it will likely take several days for your feathered visitors to get the message.

The radishes we planted this past October in our school garden are too spicy and tough for the kids to eat. What could have gone wrong?

The flavor and texture of radishes are affected by the seed variety and growing conditions. ‘Spanish Black’ is known for its peppery flavor, which may be too hot for young palates. ‘Cherry Belle,’ on the other hand, is a mild variety and a popular choice for children’s gardens. Drought stress may make radishes spicy and fibrous, too, so don’t let the soil dry out. Finally, most radishes are ready for harvest within 30 days of planting. If left in the ground longer, they can become unpalatable and woody.

What flowering plants can I grow in a pot on my north-facing apartment balcony?

Think of your balcony flower garden as a dynamic art installation that can be updated with each changing season. Hot summer days and cold winter nights pose limitations to keeping container-bound, flowering plants alive and beautiful for the entire year. Instead, plant seasonally available annuals for instant color. As we go into the warm season, try Madagascar periwinkle, celosia, portulaca, sweet alyssum and zinnias. Container plants growing outdoors will need to be watered frequently, as often as daily during the hottest months. Feed them monthly with a complete fertilizer specifically formulated for flowering annuals. When fall rolls around later this year, choose cool-season favorites, such as snapdragon, stock, dianthus and flax.

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