Cooperative Extension's March Gardening Guides

Gardening Tips for March

Average Last Frost Date

* We have had plenty of warm weather lately but don’t let it fool you into thinking it is spring. Unless you are on the outer coastal plains, the average last frost date hasn’t arrived yet. For much of the state the average last frost date is April 11. That means that 1 out of 2 years there will be a frost later than April 11. Most gardeners don’t plant tomatoes or other tender annuals until after the 90 percent frost-free date. That gives them odds of 9 out of 10 that a late frost won’t kill the plants. For the piedmont, the 90 percent frost-free date is April 15. In the mountains it may be as late as mid-May.

* In the mountains, mid-March is a good time to start tomato transplants indoors for planting in early May.

* Piedmont gardeners can plant potatoes, onion sets, beets and radishes now. You should be able to transplant cabbage, broccoli and similar members of the cabbage family but a temperature below 20 can still hurt them.

* Fertilize berry plants and fruit trees.

* Check the asparagus bed and pull weeds if necessary. Asparagus spears should start coming up in a couple of weeks.

Inviting Bees to Your Landscape

* Don’t spray any flowering plant with insecticides when pollinating insects are present.

* Consider placing a block for orchard mason bees in your landscape. The orchard mason bee pollinates spring fruit trees, flowers and vegetables. They are nonagressive and one may observe them at close range without fear of being stung. Directions for making a block from scrap lumber are on the NC State Web site .

* Ground-dwelling bees are showing up in the coastal plains and most likely will show up in the piedmont and foothills in a week or so. They may scare people but are nonaggressive and beneficial for pollination.

Lawn Care

* Cool-season lawns should have been fertilized by now. They will not need additional fertilizer until September.

* Do not fertilize warm-season grasses at this time.

* When mowing fescue lawns, don’t remove more than one-third of the blade at any one mowing (when it’s 4 ½ inches high, mow to 3 inches).

* Grass clippings should be small enough to fall between the grass blades. Don’t collect clippings unless they are heavy enough to smother the grass.

Mulch

* When using mulch near your house foundation, use mulch that doesn’t contain cellulose, such as pine needles and pine bark. The less the cellulose in the mulch, the less termites are attracted to it. Never spread mulch so that it touches the foundation or lowest course of siding on your home. While it may have a nicer appearance this way, it can allow termites to use the cover of mulch to invade your house undetected.

* Fresh wood chips along with the sawdust can be used as mulch, but do not mix into soil. It ties up nitrogen and isn’t good for plants. Also, wood chips contain cellulose so it’s preferable to use them away from house foundations.

What to Prune Now

* Prune roses. Remove all except 4 to 6 canes for big blooms. Make your pruning cut above an outward facing bud.

* Remove any old camellia blooms to prevent the spread of petal blight. Clean any dead blooms off the ground around the camellias.

* Prune butterfly bushes or buddleias, rose of Sharon and crape myrtles.