March Gardening Tips and Tasks

Planting a tree. Photo: David L. Clement

Updated: October 21, 2024

Outdoor yard and garden tips

Design a native plant garden or choose a few native plants you could grow in containers on a deck or balcony. Native plants are adapted to Maryland’s climate and soils, require less fertilizer and water to maintain, and support native wildlife including pollinators and songbirds.
Improve your soil with no-till or low-till gardening. Keep the ground covered with a mixture of plants and avoid disturbing your soil as much as possible. Smother weeds or turf (rather than digging) to prepare a new garden bed. Add compost. Good soil grows healthier plants.
Buy disease-resistant varieties of plants, if options are available. For example, flowering dogwoods, Cornus florida ‘Cherokee Brave’ and ‘Jean’s Appalachian Snow’, are resistant to powdery mildew.
Become a citizen scientist in your garden. Your observations about plant budding and flowering, bees, and birds can contribute to scientific research. Learn how you can help.

March is the beginning of the planting and transplanting season for trees and shrubs. But, avoid working or walking on wet soil; wait until the soil dries out. How do you know when your soil can be turned or tilled? A simple test is to form a clump of your soil into a ball. Bounce it up and down in your hand a few times. If it breaks apart easily it’s probably OK to dig!
Leaf scorch symptoms can occur on broadleaved evergreens. Damage is most severe on shallow-rooted plants such as azalea, rhododendron, holly, cherry laurel, boxwood, or those at their northern limit for winter hardiness (Magnolia grandiflora, Aucuba japonica, Camellia spp., and others). In many cases, damage occurs during the winter months but symptoms appear in the spring as the plant begins to emerge from the winter dormant period and move into the spring growth phase.
Prune roses starting in mid-March to maintain their shape and size. Roses typically experience some winter kill. To determine whether or not a branch is alive, simply scrape the bark with a sharp knife and look for green tissue. If it is brown prune off the cane.
If you have ash trees that need to be protected from emerald ash borer consult a certified arborist for management options.

Improve soil quality by mixing 1-inch of compost into your vegetable beds as soon as the soil is workable and not too wet.
There is still time to test the soil in your vegetable garden.
Cut back last year’s perennial herb plants like oregano, thyme, and marjoram (leave rosemary and lavender unpruned). The plants will look better and have room for new growth. This will also help reduce insect and disease problems.
Start seeds indoors: broccoli, cabbage, collard greens, peppers, and lettuce. Refer to our vegetable planting calendar.

Perennial foxglove beardtongue and wild bergamot have beautiful flowers that support native pollinators. Look for native plant sales this spring for additional options.
Many types of annual flower plants can be started indoors this month. Most are started 5-6 weeks before they are planted outdoors. Sunflowers and zinnias can be directly seeded outdoors after the danger of frost has passed.
Pansies are now widely available at nurseries and garden centers and can be planted for an early display of color in garden beds. However, it's a cool weather plant that declines quickly when it starts getting hot.
Leave old perennial flower stalks standing in the garden or cut them down to varying heights between 8 to 24 inches. These stems provide nesting sites for native bees that pollinate plants.
Divide perennials and top-dress garden beds with 1 inch of compost.

A spring application of fertilizer should not be necessary if your lawn was fertilized in the fall.
March is considered the second-best time to seed your lawn to make repairs, or to repair bare areas. The best time is late August through mid-October. Seeding should be completed by late April.

Termite swarmers can become active on warm, sunny days. If you have a swarm, it may mean that there is a colony living under or very near to your home’s foundation. The problem should be investigated, especially if swarmers are found indoors.

Look for galls on cedars and junipers to help reduce rust diseases. Handpick and destroy cedar galls by April 1, before the spore-producing tendrils are formed. Cedar galls are most conspicuous and easy to see in wet weather when the orange spore tendrils are extruded. After the orange tendrils are produced, it is too late to prevent spore dispersal.

Begin to fertilize houseplants again. The increase in natural light will prompt them to grow.
This is a good time to repot and divide houseplants. Use lightweight, well-drained soilless potting mixes that contain ingredients such as peat moss, vermiculite, and perlite.

Several species of insects are waking up from their winter dormancy inside homes. The earliest ones are multicolored Asian lady beetle, marmorated stink bug, cluster flies, and boxelder bugs. No chemical controls are recommended. They are harmless and can be swept up, vacuumed, scooped into a container of soapy water, or released outdoors.