an array of vegetable seed catalogs

Photo: Erica Smith

Updated: April 19, 2021

Outdoor yard and garden tips 

  • Many types of annual flower plants can be started indoors this month. Most are started 5-6 weeks before they are planted outdoors. Begonias, sweet peas, geraniums, and impatiens need to be started 10-12 weeks before the last expected frost. Sunflowers and zinnias can be directly seeded outdoors after the danger of frost has passed. This is also a good time to start pepper, eggplant, and basil indoors. 

  • Look for galls on cedars and junipers to help reduce rust diseases. Hand pick 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.

  • 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.

  • Cut down perennials and over-wintering ornamental grasses to within 2 inches of the ground and remove plant debris from flower beds.  Divide perennials, and top-dress beds with 1 inch of compost. Pull weeds and apply a two-inch layer of mulch to prevent weed seeds from germinating.

  • 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.

  • 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!

  • Late winter-early spring is considered the second-best time to seed your lawn make repairs, or to cover bare areas. The best time is late August through mid-October. Seeding should be completed by late April. 

  • Improve soil quality by mixing 1-inch of compost into your vegetable beds as soon as the soil is workable and not too wet.

  • Cut back last year’s perennial herb plants. They will look better and have room for new growth.  It will also help reduce insect and disease problems.

  • There is still time to test the soil in your vegetable garden. 

  • 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.

Indoor plant and insect tips

boxelder bugs
Boxelder bug adult and nymphs
Photo: William M. Ciesla, Forest Health Management International,
  • 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 beetlemarmorated stink bugcluster 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.