The Ornamental Garden in March
It’s March and the ornamental garden is emerging from its long winter sleep. Crocuses, daffodils, hyacinths, and other spring flowers are emerging from winter dormancy. Forsythia, andromeda, pussy willows, camellias, hellebores and a host of other spring-blooming plants are at their peak this month. Garden centers and nurseries are open for business with a wide selection of cold-hardy annuals for sale. And you, the intrepid gardener, are anxious to start digging in the dirt.
But hold on a minute. Despite all these early signs of spring, the soil in March is generally too cold and wet to work in. Just walking on soggy soil compresses the soil aggregates and particles. The resulting compaction affects drainage and rain infiltration and prevents plant roots from penetrating very deeply. Soil compaction also reduces the amount of open pore spaces, which makes it difficult for plant roots to absorb oxygen and water. Here’s how to tell whether your soil is dry enough to work in: Dig up a small amount of soil and squeeze it in your hand. If the soil stays in a solid muddy ball and does not fall apart, it’s too wet to work in. If the soil crumbles through your fingers when you squeeze it, then it’s ready to be worked.
Once the soil is dry enough to walk on, clean up ornamental flower beds. Remove matted leaves, twigs, and other debris. Cut back dead stems and foliage from perennials that were left standing over the winter.
Remove any weeds that have overwintered in your flower beds. It’s important to tackle weeds early and stay on top of this task throughout the growing season.
Redefine flower bed edges as needed. A flat-edged spade is very useful for this task.
Top dress flower beds with one inch of compost. This acts as a soil conditioner, which improves the soil structure and adds nutrients and moisture-holding capacity.
Assess your emerging plantings and identify perennials that need to be divided. Many perennials benefit from being divided about every three–to–five years. As a general rule, divide spring–flowering plants after they bloom; divide summer–flowering plants in late summer or fall; and divide fall–blooming plants in the spring. And here’s another tip: Hostas may be divided just as they emerge in early spring. This minimizes damage to the leaves.
If it’s been a while since you’ve had your garden soil tested or if you’ve never had a soil test done before, consider having one done now to determine the pH and to see what nutrients, if any, are deficient. For information on soil testing, check out the Virginia Cooperative Extension’s (VCE) website, which is http://www.ext.vt.edu and view Publication No. 452-129, Soil Sampling for the Home Gardener.
Finish any pruning chores that you didn’t complete in January or February. This task should be completed before plants break dormancy. VCE Publication No. 430-462, A Guide to Successful Pruning, Shrub Pruning Calendar, (https://pubs.ext.vt.edu/430/430-462/430-462.html) provides information on when to prune. It will tell you, for example, that March is a good time to prune beautyberry, boxwood, clethra and roses, among others.
Cut back ornamental grasses and liriope before spring growth appears. If you wait too late to perform this task, you may damage newly emerging foliage.
Prune roses to improve the health and structure of the plant. Make sure your pruners are sharp and clean. Prune canes to an outward-pointing bud and make each cut at a 45° angle just slightly above the bud. Remove any weak or unattractive canes. Cut any damaged wood back about one inch into healthy wood. Cut any dead canes down to the ground level. If any branches rub together, choose the healthier of the two and remove the other one. If you are pruning a grafted rose, check for suckers below the graft union and remove them. Proper pruning facilitates better air circulation, also allows more sun into the middle of the plant, and results in a healthier, more attractive plant.
Now is a good time to plant bare root, dormant roses. Soak the bare-root rose in a bucket of water for at least eight or more hours to rehydrate the roots. Choose a sunny, well-drained location, dig the planting hole wide enough and deep enough to easily accommodate the roots and set the plant so that the graft union is at soil level. Space roses far enough apart to allow good air circulation.
Clean leaves and other debris out of aquatic gardens to help reduce algae growth when temperatures warm up. Tip: If amphibians live in your pond, be careful not to disturb them. If they have already laid their eggs, be very gentle as you work around the eggs to avoid harming them.
Humans aren’t the only creatures intrigued by the early spring landscape. Deer are keenly interested in it as well – as a source of food. If deer are a nuisance in your garden, apply repellents or other deterrents as soon as the plant foliage emerges from the soil. The idea is to condition the deer to view your emerging plantings as unpalatable. Generally, no one deterrent, short of a physical barrier, is enough to stop a hungry deer. See VCE Publication HORT-62NP, Deer: A Garden Pest (http://www.pubs.ext.vt.edu/HORT/HORT-62/HORT-62.html) for more information on how to deal with deer problems. Another good source of information is VCE’s Pest Management Guide: Home Grounds and Animals (http://www.pubs.ext.vt.edu/456/456-018/456-018.html).
If you plan to grow annuals, check seed packets for guidance on the merits of direct sowing versus starting seeds indoors. Tip: If you decide to start your seeds indoors, sow them in a fine, soilless growing medium. Place under cool-white fluorescent lights about fourteen to sixteen hours per day and position the lights about two inches from the top of the seedlings. Maintain daytime temperature at 70° to 75° F and 65° F at night. Keep the growing medium moist but not wet.