March Garden Calendar

Garden Help Desk

Master gardeners will take your gardening questions at the VCE Help Desk year-round. Give us a call. We will return to farmers’ markets when possible.

Trees & Shrubs

A partial list of trees and shrubs that may be pruned in March

Deciduous trees
Beech, catalpa, crape myrtle, ginkgo, hickory, honey locust, linden, mulberry, black gum, oak, sourwood, stewartia, sweetgum, sycamore, tulip tree, zelkova. Engage a pro to prune large versions of these trees.

Evergreen trees
Cedar, cypress, fir, hemlock, evergreen holly, juniper, Leyland cypress, magnolia, pine, spruce.

Abelia, arborvitae, boxwood, butterfly bush, cherry laurel, clethra, cotoneaster, red-twig dogwood, gardenia, deciduous holly, juniper, nandina, osmanthus, photinia, privet, smoke tree, sumac, yew.

Other perennials (cut back to 8 inches)
Bush lespedeza, Russian sage, caryopeteris divaricata, false aster, aster, coreopsis, baptisia, beautyberry

Other perennials (cut back to 1/3 of full size)
aster, Montauk daisy

Prune all dead, damaged or diseased branches any time of the year


Provided your soil is dry enough, this is a good time of year to aerate your soil. Engage a company to do it or rent a core aerator. Follow the aeration with a top dressing of compost.

Last chance to service your mower before the mowing begins in earnest. At the very least, your mower needs a sharpened blade and an oil change. It may need a new air filter and spark plug as well. And don’t forget that leaving gas in the mower’s fuel tank over the winter is a very bad idea. You may not be able to start it in the spring.

Crabgrass prevention
Buy pre-emergent crab grass killer for use next month. You will be putting down this material in early to mid-April depending upon temperature. Do NOT buy a combination weed and feed product. The right time to apply crabgrass preventer (while the forsythia is in full bloom) is the wrong time to add fertilizer to your lawn.

Winter weeds
When temperatures are above 50 degrees F, treat winter broadleaf weeds such as chickweed, henbit, dead nettle, hairy bittercress, and geranium. To choose the proper herbicide, it is necessary to identify the weeds. Call the VCE Help Desk for assistance.

If you didn’t lime in the fall, early spring is a good time. Ground limestone is fairly insoluble. It takes most of a year for the lime to have its full effect on raising pH. Liming should be based on a soil test. Soil test kits are available at public libraries in the County.

If you still have bare spots in your lawn, early spring is the second best time of year for spreading grass seed (late summer to early fall is the best). Grass seed will germinate and come up strong in the spring. The tough part is getting a newly sprouted lawn to survive through our hot and sometimes dry summers.

Vegetable Garden

Working the soil
It’s tempting to start digging in the garden on nice days in March, but you must take care not to compress wet soil. This causes compaction that ruins soil structure. Pick up a handful of soil and squeeze it into a ball. Now drop it from a height of 3 feet. If the ball shatters into many pieces, the soil is dry enough to be worked. If it keeps its shape or maybe breaks into a few large pieces, it is too wet to be dug.

Raised beds and cover crops
You can cheat a little bit on working wet soil if you have raised beds because you will not be standing in the beds while you dig them. If you have a cover crop such as annual rye, you will need to begin to turn the rye into the soil in late March or early April to give it enough time to decompose and return its nutrients to the soil before you plant that bed in May. Turn it with a shovel first and finish it off with the rototiller a couple of weeks later.

Onion plants
If you have bought onion plants from a seed company, they will likely be delivered on or about the 15th of March. Follow directions in the box to care for the seedlings until you can plant them in the ground. They should be planted within a week or 10 days of delivery.


Most spray programs to control insects and disease should begin in March in our area. For details consult the 2020 Virginia Pest Management Guide, Home Grounds and Animals, Section 3: Home Fruits: Disease and Insects

Flowering Annuals, Perennials

This is a good time to start acquiring seeds of flowering annuals to start inside.
Poppy seeds may be spread outside on the soil surface.


Scouting for Pests
Don’t take your houseplants for granted. Inspect them regularly to detect the onset of pest problems. This month, you may begin to see small numbers of aphids, whiteflies, mites or mealy bugs. Keep the problems from exploding by bathing the plants in a spray of warm water or water containing an insecticidal soap. Make sure to wet all parts of the plant thoroughly. A cotton swab dipped in rubbing alcohol is good for removing small numbers of mealy bugs and aphids. Take care not to overdo it with the rubbing alcohol; too much will harm some plants.

Most houseplants should be watered when the surface of the soil feels dry. Add water until it runs out the bottom of the pot. If the soil has pulled away from the pot’s rim, it is much too dry. Soak the pot in a bucket of water to restore the proper moisture.

Home Fruit: Diseases and Insects, 2021, Virginia Pest Management Guide, Home Grounds
   and Animals
A Guide to Successful Pruning, Shrub Pruning Calendar, 2009, Virginia Cooperative
   Extension Publication 430-462
A Guide to Successful Pruning, Deciduous Tree Pruning Calendar, 2009, Virginia Cooperative
   Extension Publication 430-460
A Guide to Successful Pruning, Evergreen Tree Pruning Calendar, 2009, Virginia Cooperative
   Extension Publication 430-461
Indoor Plant Culture, Virginia Cooperative Extension Publication 426-100