Timing is everything when your goal is a beautiful lawn and garden. These March gardening tips and chores apply to USDA Plant Hardiness Zones 5 & 6, which encompass Western Pennsylvania.
Flowers & Vegetables
- If you'd like to try your hand at growing your own plants, March is the time to start indoor seeds of tomatoes, peppers, eggplant, and other warm-season veggies. Tomatoes are best started late in the month to avoid ending up with leggy plants come May.
- When your garden is dry enough (feels crumbly like chocolate cake, not squishy like Play-Doh), it's time to till and prepare it for planting. Take a soil sample to your Penn State county extension office to be analyzed, and work in fertilizer and other nutrients as indicated.
- St. Patrick's Day is the traditional time to plant peas and potatoes, but you may have to wait a few weeks until the ground dries out unless you prepared the soil last fall. Rhubarb, asparagus, and onion sets can also be planted now.
- Remove mulch covers from roses, azaleas, clematis vines and other tender shrubs once nighttime temperatures rise into the 30s (be prepared to recover if a late cold-snap hits). Leave mulch around spring flowering bulbs and tender perennials, however, as it will provide protection to emerging shoots against cold, drying winds.
- Trim back winter-killed rose canes to one inch below blackened area and all rose canes to about six inches above ground level. Cut back any perennials that weren't cleaned up last fall, as well as ornamental grasses.
Trees & Shrubs
- Prune fruit trees, bramble fruits, and grapes (except peaches and nectarines, which are best pruned before they flower) before the buds swell.
- Prune summer and fall blooming shrubs now (wait to prune spring blooming shrubs such as azealeas until after they bloom). Delay pruning evergreen shrubs and hedges until early summer.
- Apply dormant oil spray to any trees and shrubs (except blue spruce)that are plagued by scale insects or mites.
- Now's the time (before it gets too hot and dry) to plant deciduous and evergreen trees and shrubs, weather and soil conditions permitting.
- Fertilize established rhododendrons, azaleas, roses and other ornamental trees and shrubs, as well as fruit trees. Follow the recommendations on the fertilizer bag.
- Fertilize your lawn with either an organic or a chemical fertilizer and treat lawns, as necessary, for crabgrass or annual bluegrass problems with a pre-emergent preventer (watch for air temperatures above 60° F for 4-5 consecutive days for the right timing). Consider a product that combines the two to save on application time.
- When weather conditions permit, remove excess thatch from your lawn and aerate it, if necessary.
- Fertilize established lawns.