From August to Autumn with P. Allen Smith

Writer Ellen Jordan
Photographer Jane Colclasure

Late summer is ripe with opportunity for mid-Southern gardeners. August brings with it more than just a need to water thirsty yards and plants. In fact, according to P. Allen Smith, August is the ideal time to prepare lawns, beds and containers for fall. Despite the heat, which in the mid-South can last into October, this month is the time to purchase plants, clean up and harvest.

A nationally recognized horticulturist, garden designer, television host and author, Smith studied garden history and design at the University of Manchester in England through an International Rotary Scholarship and became a Certified Fellow of the Royal Horticultural Society. Upon return to the U.S. more than 25 years ago, he established a goal to inspire, teach and encourage Americans to embrace gardening as a joyful and fulfilling pastime. As autumn approaches and Smith begins to prepare his personal garden for the change in season, he shares advice for mid-Southerners who’d like to do the same.

With regard to plants and flowers during this part of the year, Smith relies on varieties that will provide the beautiful, deep colors of fall. Favorite perennial choices include Salvia 'Indigo Spires' and Hostas. For annuals, his choices include ornamental cabbage and Lantana. Smith also utilizes ornamental grasses like ribbon grass and Miscanthus 'Caberet.' "I see autumn as a second chance to enjoy my garden as it dons a new coat of vibrant colors," he explains. "While the spring garden is a tapestry of pinks, soft blues, chartreuse, grays and creams, by fall, the blooms and foliage transform into deep purples, oranges, reds and yellows."

Another aspect of garden preparation in August involves transforming planters around the home. Smith recommends a revamp of container gardens with "slip-in" plants to replace tired summer flowers. "Some substitutes I rely on include old standbys like kale, pansies, snapdragons or ornamental grasses, but some new covers from Proven Winners' Fall Magic Collection, like Flambe® Orange Chrysocephalum, Sundaze® Flame Strawflower, and cheery phlox varieties Intensia® Cabernet and Intensia® Lavender Glow are also a nice choice for giving your container gardens an autumnal glow."

Another late summer garden task involves separation of daylilies. Because these plants grow vigorously, often doubling in number from year to year, they require division to maintain continual blooming and growth. Smith’s advice is, after three to five years, thin the beds and transplant excess flowers during late summer. August is a good time to move these plants because the daylilies have time to settle into the new ground before the days shorten and temperatures cool. Simply use a shovel to separate the clumps; shake the excess soil from the roots; remove dead foliage; cut the plants back about halfway; and transplant in the new location.

Smith offers a guide for the upcoming months to help gardeners keep track of what to do and when. By following his guidelines and seizing the August gardening opportunities, mid-Southern growers are sure to find their gardens in gorgeous shape when fall finally arrives.

In August:

• Stop fertilizing roses.
• Stop deadheading your repeat blooming roses so they can produce rose hips for fall.
• Late summer and early fall are the times to treat your lawn for grubs, which mature into Japanese beetles and attract digging animals such as moles and raccoons. A small number of grubs are beneficial, but if you have more than 10 per square foot or have a problem with foraging animals tearing up your lawn, now is the time to take action.
• Get your orders placed for spring flowering bulbs. Try my favorite tulip combination: 'Perestroika,' 'Menton' and 'Temple of Beauty.' It’s a fiery blend of salmon, pink and orange.
• When selecting mums, go for healthy looking plants with moist soil in the container. Dry soil conditions cause stems to shrivel and cut down on blooms. And for a longer flowering time, select plants that are heavily budded rather than in full bloom.
• As you begin your fall garden clean up, be sure to remove and throw away diseased foliage, but don’t put it in the compost pile. This will help prevent fungi, like black spot and powdery mildew, from carrying over to next year.

In September:

• Add well-rotted manure and organic humus to your flowerbeds. Your plants will thank you for it next spring.
• Keep treating roses, lilacs and phlox for powdery mildew.
• Begin moving your houseplants indoors before the first hard frost. The best time to make the move is when inside temperatures are similar to those outdoors. Wash the leaves with a diluted mixture of mild soap and water. This will help your plants breathe and respond better to light. Then, to eliminate any pests they may have picked up during the summer, treat with an insecticidal soap.
• Early fall is the best time to sow many types of wildflower seeds. The key to success is to make sure your plants have enough time to germinate and establish themselves before the first hard frost. That’s usually about eight weeks.