The Ornamental Garden in March
Hallelujah! March has arrived and with it, the first stirrings of spring! Although you may see buds swelling and spring bulbs emerging, don’t rush out to your flower beds with garden tools and seed packets in hand just yet. March is a fickle month. The weather can be cold and blustery one day and warm and pleasant the next. Until the weather becomes consistently milder, use this time to get organized. Make a list of all the tasks you want to accomplish in the garden this month. Perhaps the following suggestions will provide inspiration.
Tidy flower beds. Avoid walking in your flower beds if the soil is wet. Instead, reach into them to remove matted leaves, twigs, dead limbs, and other debris that accumulated over the winter.
Remove any weeds that have overwintered. It’s amazing how quickly weeds can get out of control in the early spring. Tackle them now (again, avoid walking on wet soil) before they take over.
Redefine bed edges. The soft soil will make it easier to edge. Tip: You can use a weed whacker for this task but it’s better to use a sharp straight-edged shovel or a half-moon edger to cut an edge about 2 in. straight down on the grass side. This will keep the grass from growing into the bed. As you redefine the bed edge, scoop loosened soil in toward the flower bed.
The result should be a neat straight edge with soil gently mounded away from the trench.
Prepare a soil sample to have it tested for pH and nutrient content. On average, a soil test should be conducted about once every 3 years. Contact the Virginia Cooperative Extension (email email@example.com or call 434-872-4583) for instructions on how to get a soil test done or check their publication 452-129, “Soil Sampling for the Home Gardener” (pubs.ext.vt.edu/452/452-129).
Cut back perennials that were left standing over winter. Wait until the latter part of March or even early April to complete this chore.
Finish any pruning tasks that were not completed in February. This includes cutting back ornamental grasses before new growth emerges. Tip: You can use a lawn mower set at 2 to 3 in. to cut back Liriope. Don’t cut it any lower than that or you may damage the crown of the plant.
When performing late winter or early spring pruning tasks, don’t forget to cut back subshrubs. These perennial, generally low-growing, shrubs have woody stems except for the new growth’s terminal part, which dies back annually. Examples of subshrubs include:
- Butterfly bush (Buddleia) — Prune back all stems to about 1 to 2 ft. from the ground.
- Blue mist shrub (Caryopteris) — To neaten the shrub or encourage new growth, cut back by about a third. To rejuvenate the shrub, cut back to about 6 in. from the ground.
- Russian sage (Perovskia atriplicifolia) – Russian sage foliage is generally best left standing in the fall to provide winter interest and to help protect the crown. In early spring, cut back the old foliage to within 6 in. of the crown.
- Lavender cotton (Santolina chamaecyparissus) – Cut back to within 6 in. of the crown every 2 to 3 years.
- Heather (Calluna vulgaris) – Prune flower stems back to the base of old flowers. Snip the green part only. Don’t cut down to the brown woody portion.
Cut back to green wood any tree or shrub twigs that were affected by winter kill. On smaller twigs, scratch the bark with your fingernail to determine whether it is alive.
Plant bare-root (dormant) roses after the ground thaws but is still cool and moist without being overly wet. Generally, this means planting from 6 weeks before until 2 weeks after the last frost. Check the canes to make sure they are green and healthy and not dried up. Tip: For best results, buy No. 1 grade roses with at least 3 to 5 well-developed canes that have not yet leafed out. If you’re not sure how to plant bare-root roses, here are a few pointers:
- Before planting bare-root roses, unwrap them from their packing and soak the roots in a bucket of water for about 8 to 12 hours to rehydrate the roots. The entire plant may be immersed to rehydrate the canes. After soaking, prune any roots that are damaged, diseased, or too long.
- Dig the planting hole wide enough and deep enough to comfortably accommodate the roots. Set the plant in the hole and spread the roots evenly around it. For grafted roses, position the plant so that the bud union (the swelling at the base of a grafted plant where the new plant was grown on the rootstock) is slightly below the soil surface. This will protect it from freezing in the winter.
- Backfill the planting hole until it is two-thirds full with soil that has been amended with well-rotted manure or compost. Gently firm the soil to ensure good contact between it and the roots. Add water to settle the soil and eliminate air pockets. After the water drains, add more amended soil to fill the hole and water again. Don’t tamp the soil because that compacts it.
- Spread 2 to 3 in. of mulch over the root zone to help keep the soil cool and to retain moisture.
- Water the plant about once a week after growth commences. While moisture is important, don’t go overboard. Too much water may rot the roots.
Although you probably yearn to be outside working in the soil, don’t lose sight of the continuing needs of your houseplants. Monitor moisture and humidity levels, check for pests, and continue giving each pot a quarter turn every so often so that they don’t learn toward the light.
Start feeding houseplants with a diluted solution of soluble houseplant food.
Pinch back houseplants that have grown leggy over the winter. Pinching causes the plant to fill out and grow fuller looking. Wait until the end of March or early April to complete this task.
Refresh the bark-growing medium for orchids. Bark tends to break down over time, which may affect aeration at the root zone. Depending on the type of orchid you have and its specific requirements, replace the bark about every 18 to 24 months.
Check to see if houseplants need to be re-potted. Spring is a good time to repot houseplants before the active growing season begins. If you can see roots on the surface of the soil or emerging from the drainage hole in the bottom of the pot, the plant is root-bound and needs to be re-potted into a larger container. Here are a few tips on how to re-pot a houseplant:
- First, choose a pot that is about 1 to 2 in. wider and deeper than the current pot. If you select too large a pot, the visible part of the plant won’t grow until the roots begin to fill up the pot. IMPORTANT: If you’re re-using a pot, scrub it first to remove any traces of old potting soil or other debris that might harbor plant diseases. Rinse the pot well (particularly if you disinfect it) and allow it to dry.
- Turn the houseplant on its side and gently work it out of the current pot. If it won’t budge, tap the pot on a hard surface to see if that will free the plant. If it doesn’t, you may need to slide a knife or trowel around the inside of the pot to work the root ball free. Just be careful not to damage the root ball.
- Examine the roots once they are freed from the current pot. If you see a lot of roots coiled around the bottom of the root ball, loosen them, stretch them out, and snip them off. That will stimulate the plant to develop new roots.
- Partially fill the new pot with potting soil. Position the plant so that it is centered on top of the soil. Finish filling the pot with the potting soil, leaving about an inch gap between the top of the soil and the top edge of the pot.
- Slowly add water to moisten the roots and to help settle the potting mix. Add more potting mix if necessary.
- Keep the soil evenly moist, but not soggy, while it is adjusting to the new pot.
- Wait about a month to allow new roots to develop before fertilizing the plant.
Finally, here’s one more item to add to your “to do” list. If you plan to grow annuals and perennials from seed this spring, buy the seeds SOON before the choice selections are all gone.