August Horticulture Hints

The humid, hot days of August have been referred to as the “dog days of summer.” It is the time when, as a child, I believed that dogs and foxes “went mad.” I thought that if I got bitten by a rabid animal, I would go mad, too, and die a horrible death. Still, I’m wary of rabid animals. Even so, with one eye cocked toward the woods, I find much to do in the garden during the dog days.

Groom and Fertilize

Groom the garden by deadheading (removing old flowers) annuals and perennials. Pinch back annuals that have gotten too leggy. Lightly prune such annuals and perennials as begonias, salvias, artemisias, and coleus to rejuvenate them for the fall season. Prune out spent flowers and weak stems and shorten the remaining stems by about one-third. Do not, however, prune too heavily, or your plants may be severely damaged or even killed. Apply a light sprinkling of fertilizer or compost.

Mulch

Spread grass clippings on mulched areas if they are not left on the lawn. Leaves work well if mixed with other materials. Maintain a two- to three-inch layer of mulch on the soil surface beneath plants, but be sure to pull it away from the base of plants to prevent crown rot. As organic mulches decompose, they enrich the soil, lessening the need for chemical fertilizers. Most well-established shrubs and trees that have been supplied with a good layer of organic mulch usually do not need additional fertilizer. Mulch can provide a design element in the landscape by adding a contrast of color and texture that complements plantings.

Evaluate and Take Action

Evaluate your landscape and remove plants that are not growing well because they are not adapted to the site or are doing poorly because of the ravages of pests or diseases. Take a hint from Mother Nature. If plants begin to die, replace them with hardy, pest-resistant plants that are better suited to our climate.

Watch crape myrtles for aphids. A telltale sign is sooty-looking mold which grows in honey dew secretions and causes a heavy film on the leaves. Use insecticidal soap for control.

Continue to prune back the plants in container gardens to keep all components in scale. Some of the plants from spring have surely expired, and those that have lasted this long have probably have outgrown their space. Replace spent or overgrown plants with some saucy new ones, and add a complete, slow-release fertilizer. Sufficient water is critical to the survival of containerized gardens. They often need to be watered daily.

Solarize

If insects and diseases have been a problem in flowerbeds or vegetable gardens this summer, consider solarizing the spot. First dig in organic matter to make the bed ready for planting, and then cover the soil with clear plastic sheeting. Seal around the edges and let the soil bake in the sun for about six weeks. By the time the solarization process is complete, it will be time to plant seeds for the winter garden. Simply remove the plastic covering, water the soil thoroughly, and sow seeds.

Plan, Plant, and Propagate

• Sow seeds of summer annuals to replace those that burn out in the heat. Try threadleaf zinnia, ‘Profusion’ zinnia, portulaca, melampodium, globe amaranth, and ornamental peppers. These flowers will add color until frost cuts them down if they are started now.

• Buy seeds for broccoli, cabbage, beets, cauliflower, mustard, turnips, carrots, collards, kale, and lettuce, and get ready to plant them when the weather cools a bit.

• Get ready to spruce up the herb garden. Purchase seeds for parsley, sage, thyme, coriander, dill, fennel, and rosemary. Plant in late September.

• Set out tomato plants for a fall crop. Try heat-tolerant varieties such as Solar Set or Heat Wave.

• Root cuttings of woody perennials such as Angel’s trumpets, Turk’s cap, oleander, gardenia, azalea, camellia, hydrangea, salvias, clerodendrons, firespike, and firebush. Over-winter in a protected place, and they will be ready to add to the landscape next spring.

• Ginger lily, oxblood lily, and Lycoris can be planted now.

• Collect seeds as they ripen on perennials and annuals. Place in envelopes with the species and date collected. The bottom of the refrigerator in a tightly sealed container is a good place to store seeds.

• Continue to prune back the plants in container gardens to keep all components in scale. Some of the plants from spring have surely expired, and those that have lasted this long have probably have outgrown their space. Replace spent or overgrown plants with some saucy new ones, and add a complete, slow-release fertilizer. Sufficient water is critical to the survival of containerized gardens. They often need to be watered daily.

Flowers of the Season

Enjoy fall-blooming perennials such as, butterfly weed, Salvia guaranitica, pineapple sage, Mexican sage, autumn sage, ginger lilies, and others. Plan to add some of these to your landscape this fall or next spring

Many plants combine to make the August garden truly memorable. Look for the blossoms of several woody perennials such as blue butterfly bush and other Clerodendron species, Philippine violet, firespike, firebush, cigar plant and other Cupheas, plumbago, and lantana. Shrubs like abelia, althea, crape myrtle, hibiscus, turk’s cap and oleander add color. Fall-blooming herbaceous perennials such as butterfly weed purple coneflower, various salvias, black-eyed Susan, and others bloom unabatedly as fall progresses.

Many bulbous perennials decorate the August garden. Ginger lilies, crinums, and cannas bloom. If we’re lucky, spider lilies (Lycoris spp.) will be rising up on their naked stems toward the end of the month.

Among the annuals that have bloomed most of the summer are gomphrena, marigold, melampodium, pentas, periwinkle, portulaca, purslane, torenia, wax begonia, and impatiens. Foliage plants like caladium and coleus add considerable color to landscapes. Ornamental grasses bloom on tall stems that sway in the slightest breeze.