Gardening Blog

Want your Lowcountry garden to survive June’s heat and humidity? Be ‘thoughtful’

Blue Evolvulus backed by purple Mexican Heather make an attractive pairing.
Blue Evolvulus backed by purple Mexican Heather make an attractive pairing. Special to The Island packet/ The Beaufort Gazette

Outdoor temperatures and humidity levels are rising, late-spring shrubs and perennials are finishing their bloom cycle and early-summer blossoms are now making their appearance. Is it now too late to plant ornamentals? No, not if you make thoughtful choices.

What is included in being “thoughtful?” What is your vacation schedule from now through September? What if you need to be away for a while due to a sudden family emergency? If you will be away for more than forty-eight hours, do you know someone who can check that your new plants receive regular watering?

If you have an automatic sprinkler system, your new in-ground plants are likely to receive adequate moisture. They may also receive too much water if heavy summer storms occur during your absence. Plants in low-lying areas where water drains slowly are most vulnerable to being flooded. In addition, hanging baskets and containers dry out very quickly, so consider enlisting the assistance of a knowledgable garden friend to monitor your landscape in either case.

After preparing the soil properly, the next rule in gardening is to plant the right plant in the right place.

It is better to know in advance the site conditions of areas around your home (sun, shade, exposed, protected) and select plants that meet those conditions, rather than pick plants and then try to find a place for them. Know the ultimate sizes of plants and allow for that growth. Do not plant shrubs which will eventually cover windows or block entrances. In addition, avoid overplanting. You are better served with a few plants that are well-placed than with a lot of small ones.

Clemson University advises that “shrubs of more than six feet tall at maturity should be located so that their foliage will be at least five feet away from the walls. Shorter shrubs should have at least a three-foot clearance between them and the house. This allows for adequate air circulation for house foundation vents and helps prevent mildew. Allow adequate spacing between plants also, to prevent later crowding and excessive pruning.

Symmetrical balance is often overused in designing home landscapes. Although easy to accomplish, it is overly formal for most homes and has a stiff appearance. Asymmetrical balance is often more desirable for residential landscapes as balance is created without monotony.”

Drier soil cuts down on mildew problems and moisture damage and discourages insect pests like termites and roaches. “Never pile mulch high enough to touch the siding on your house, as that just gives termites easy access to wood siding.” advises Jennifer Howell of Garden Gate Magazine.

Small ornamental trees can be located near a corner or as an accent in the area near a door. Good choices are redbud, Japanese maple, crape myrtle, and star magnolia. Treeform evergreen shrubs such as wax myrtle, burford holly, and some ligustrum varieties can also be used in small areas.

Grass-like plants such as mondo grass, Aztec grass, and liriope grow in attractive grassy mounds that can put just the right finishing touches on any landscape. These three are tough, evergreen, low-maintenance plants. Their size and form work well for borders and edging. The flower spikes are tucked down in the dense grass and, other than liriope blossoms, aren’t usually very visible.

Groundcovers are flattering to most Southern house styles. A continuous planting of one kind of groundcover can tie plantings together, creating unity among groups of shrubs or among trees and shrubs. Groundcovers can be used to provide a natural and attractive edging for the lawn. A flowering groundcover plant suitable for the Lowcountry is evolvulus (Evolvulus glomeratus). This sun-lover has blue summer-to-fall flowers. Often used in hanging baskets and containers, when evolvulus is grown as a ground cover plant it forms 9- to 18-inch-tall mounds of sprawling foliage.

Perennial plants can provide seasonal interest and colorful accents. It is important to choose perennials that look good both in and out of bloom. Consistent performers in our area include: black-eyed Susan, salvia, lantana, agapanthus, and blue star (Amsonia).

Annuals should be chosen for long bloom and ease of care. Make sure that these plants receive regular maintenance. Examples of annuals that grow well here include: angelonia, impatiens, portulaca, pentas, melampodium species, and coleus.

With careful consideration, you can plant ornamental trees, shrubs and plants now, despite current humidity and temperature levels, thereby enhancing your landscape.

Frank Edgerton is a Hilton Head Island resident, garden consultant and plantsman. He can be reached at