Heat and Drought Tips and Tidbits for the Garden

From M & M Landscape and Lawn, Inc.'s July, 2006 Newsletter

As if gardening chores aren't strenuous enough by this time of year, Mother Nature's heat wave is making life even more difficult. It seems as if a mid-summer drought is a fact of life in the Southeast. In recent years drought periods have ventured into spring and fall. There are a few things you can do to ease your plants discomfort and ensure their livability during these periods of heat and drought.

Newly set transplants will require more frequent watering and will benefit by shading from midday sun to avoid wilting. In some cases, plants will wilt during midday despite all your effors simply because the leaves are losing moisture faster than the root system can take up water. In this case, the plants should recover in the evening and morning hours when temperatures are cooler.

Container plants on the patio will be streesed by the heat wave since they have much less buffering of temperature extremes on the root system. In addition to watering more frequently in hot weather, provide afternoon shade, if possible, to help keep them a bit cooler. Also, consider planting your container plants in some of the newer lightweight foam planters that are available. The thickness of the form containers will provide some insulation between the plant's roots and the heat of their environment. Be sure to drill drainage holes in the container if none are present.

HGTV personality and Master gardener Paul James fields view questions about hot-weather gardening:

Q. What does drought-tolerant really mean?

A. The term drought-tolerant is used to describe plants that will grow well with little, if any, supplemental water. However, what is often lacking in that description is one key phrase, namely, "once established". I'm not aware of a single landscape plant that you can simply stick in the ground and expect to grow without water, especially during that first critical year.

It's during the first critical year of growth that plants become established, meaning they develop a healthy root system and become acclimated to the soil, the weather, basically the whole environment. Some plants take longer than others to become established. So make sure you water new plantings routinely, as often as everday or as little as once a week, depending on the type of plant and it's requirements, until it seems capable of supporting itself with only the occasional watering or from rainfall alone.

Q. During the heat of summer, isn't it better to water landscape plants every day?

A. Watering daily during the summer is absolutely not a good idea, because even in the middle of summer, you can overwater plants. Even if you water lightly, the water won't penetrate very far which means roots will hover near the surfact of the soil. It's important to water once or twice a week in a manner that it percolates deep within the subsoil. By deep-soaking, you encourage roots to likewise venture deeper into the subsoil in search of water. And as a result, those plants are far better equipped to handle drought conditions.

Q. How can plants make the environment cooler?

A. Plants make the environment coller, thanks to a process called evapotranspiration. Take an oak tree, for instance. As it secretes, or transpires, moisture through it's leaves, this water draws heat as it evaporates, thus cooling the air in the process. Incredibly, a large oak tree can easily release up to 40 gallons of water in a single day. When combined with the shade it casts, trees can make a huge difference in energy costs when planted on the south and west sides of a house.

Q. What are some of the most heat-tolerant perennials?

A. Thankfully there are lots of them, and the following plants are a few of my favorites that are readily available, establish theselves quickly and grow magnificently throughout much of the country. Topping the list are the ornamental grasses. Once established, ornamental grasses are among the most drought-tolerant and carefree plants on the planet. Once more, they're beautiful in almost any setting throughout much of the year. Daylilies are another sure thing. Because they bloom for months you get a lot of bang for your buck. Despite it's dainty appearance, coreopsis is tough as nails and can really take the heat. The same can be said for coneflower (Echinacea) and black-eyed Susan (Rudbeckia). In fact, you could create a terrifc drought-tolerant garden with just those five plants. Of course, you could also add iris and a number of evergreens, such as junipers, spruces, and pines. Finally, there are the obvious choices, cacti and succulents which make outstanding additions to the landscape or look great in containers, too.

One last thought on heat and drought tolerance in plants. If you haven't already done so, mulch, mulch, mulch. Mulch is invaluable around the root zone of your plants to help hold in what moisture is avilable to the plants to help them through the heat and drought.

Try not to overdo the garden work in the heat, over-exerting yourself in extreme hot weather can be very dangerous to your health. Aim to complete your chores very early in the morning, take frequent breaks, and drink plenty of water to keep yourself from wilting.

VACATION TIME

July represents vacation time for many people and the McAnallys (of M & M Landscape and Lawn, Inc. fame) took theirs recently. One stop was particularly interesting and we thought we'd share some of it.

We toured Bellingrath Gardens in Theodore, Alabama, right outside Mobile. Tours are offered for both the Bellingrath Home and Gardens. They offer, in addition, a waterfront cruise of the surrounding estates and wildlife. The Bellingrath Home, completed in 1935, has been featured on "A&E's America's Castles". More than 70 years ago, Walter aned Bessie Bellingrath began a horticultural endeavor that would become one of the South's preeminent gardens. From it's humble beginnings as a fishing camp, Bellingrath Gardens showcase the natural beauty of the Mobile Bay area. Nestled among oaks, Spanish Moss and the scenic Fowl River, the 65 acre gardens of Bellingrath are said to boast a bloom every day of the year. We chose to take in only the gardens, and they were magnificent. True to their word, blooms did abound. Using mature evergreen Camellias and Azaleas reaching 8 feet tall as a backdrop, serpentine rows of colorful annuals weaved throughout a large portion of the gardens. The rose garden constructed in 1935 with it's adjoining Conservatory, contains more than 2,500 plants representing more than 50 varieties. Just image 2,500 roses in full bloom!

Pictured is a shot of "Rebecca at the Well" a bronze relief commemorating the Old Testament heroine described in Genesis 24:15. The fountain beyond marks the site of an artesian well dug during the Bellingrath's search for good drinking water.

The gardens were handicapped accessible with wide paved pathways throughout.

For more information on Bellingrath Gardens and Home: Phone: 800-247-8420 or go to their website at www.bellingrath.org.

SPOTLIGHT ON CRAPE MYRTLE

Lagerstroemia indica, Lay-ger-stree'mee-a, Crape Myrtle. Deciduous tree or shrub, Zone 7. Heights: Range from true miniatures under 3 feet tall to tree form up to 25 feet tall.

Crape Myrtle has spectactular blooms from summer until frost.

Small flowers in large clusters have a texture like crepe paper and come in many shades of pink, rosy red, purple or white. The leaves are smooth ovals, 2-4 inches long, sometimes turning red, orange, or purplish in fall. Grey-tan outer bark flakes off the handsome muscular-looking trunks to reveal smooth mahogany inner bark. Cultivars vary in flower, color and ultimate size; some are dwarfs only 3-5 feet tall. Trees may be trained as single-trunked or multitrunked specimens. Dwarf shrubs add summer color to mixed hedges or borders.

How to grow: Full or part sun. Ordinary soil and watering. Thrives in hot weather and tolerates dry soil. Blooms on new growth; if shoots freeze back in a severe winter, it will recover the same year. Pruning and thinnning can produce larger flower clusters but aren't necessary. If you must prune, do so in November or December or while still fully dormant. It's better to plant a dwaft cultivar than to chop back a big tree form each year. Remove suckers at the base of large tree form varieties to expose and feature the trunks.

Some varieties of Crape Myrtle are naturally more susceptible to powdery mildew than others. Fungicide sprays such as Immunox, Daconil or Funginex will help.

Popular varieties of miniature weeping forms (reaching 2'-3' tall) are: Sacramento (red), Delta Blush (pink), New Orleans (purple), and World's Fair (watermelon red).

Popular varieties of true miniatures (reaching 12"-18" tall) are: Coral Filli (coral), Red Filli (red), and Pocomoke (rose-pink) which can reach up the 2'.

Popular dwarf varieties (reaching between 3'-6' tall) are: Pink Ruffles (light pink), Royalty (lavendar), Snow (white), Victor (dark red), and Tightwad Red (light red).

Popular medium varieties (reaching between 8'-10" tall) are: Acoma (white), Hopi (pink), Tonto (red), Zuni (lavender).

Popular tall varieties (reaching 20'-30' tall) are: Basham's Party Pink (lavender-pink), Natchez (white), Tuscarora (coral-pink), and Biloxi (pale pink).

BAGWORMS

Two insects are commonly called bagworms. The large tent forming caterpillars or webworms which are in actuality tent caterpillars, and the small bag forming insects known to plauge junipers and cedars, called bagworms.

Bagworms are caterpillars that make distinctive cone-shaped bags on a variety of trees and shrubs. The bags are formed from the plant material the insect is feeding on. While bagworms attack both deciduous trees and evergreens, they are most damaging to juniper, arborvitea, and cedar. Unless the plant is small or stressed to begin with, it usually takes a couple of years infestation of bagworms to completely strip a plant of its foliage and eventually cause it's death. Of course, large populations of the pest can accomplish this feat faster. Rarely do people notice the damage until it is past the time when sprays are effective and the damage is done for that year.

Bagworms are the caterpillar stage of a moth that is rarely seen. Only the males develop into typical moths capable of flight. The adult female is grub-like and remains inside the bag until just before she dies. Bagworms overwinter as eggs within bags fastened to twigs. Eggs hatch in May and early June. Almost immediately after hatching, caterpillars begin to spin tiny protective cases or "bags" around themselves. The bags are constructed of silk and needle fragments or leaaves. As the bagworm grows, leaf fragments are added to the bags which often grow to 2 inches in length by the end of summer. The bags protect the caterpillar from predators and insecticides. Adult males emerge from the bags in September as small black, clear winged moths, and fly around locating a female to mate with through the females bag entrance. The females are wingless and never leave the bag. The females can produce 500 to 1,000 eggs, after mating, which are deposited inside their bag. The female then dies, never leaving the bag. At this stage, spraying is ineffective. Hand pick and destroy the bags before next spring to prevent reinfestation.

If you are having a continual problem with bagworms, it may be necessary for you to begin spraying weekly from May through mid June with Dipel, Thuricide, or Sevin to attack the small larvae before they have a chance to make their bags.

BLACK SPOT ON ROSES

If you've ever tried to grow a Hybrid tea rose, chances are you have had an encounter with Black Spot on Roses. Black Spot is caused by a fungus (Diplocarpon rosae) and is the most widespread disease of roses in Arkansas. Although the fungus may affect most rose varieties, Hybrid tea roses are by and large the hardest hit.

The optimum weather conditions for disease development are 75 deg. to 85 deg. farenheit with a relative humidity or rainy periods. When leaves remain wet for six or more hours, the fungus infects them. Canes can also be infected.

Symptoms:

Leaf spots are the most characteristic symptoms. The spots are round, with feathered edges and up to 1/2 inch across. Spots appear mostly on the upper surface of the leaf and often have a yellow halo around them. When many spots are present on the leaves, the leaves will turn yellow and fall off. Lower leaaves usually bcome infected first. Excessive leaf drop from this disease weakens the plant, resulting in other problems. New spots can appear in as little as five days when conditions are favorable for infection.

Cane symptoms are less obvious. Small, purple blister-like blotches appear on the canes. These blotches become black with age. Cane infections are very important in the survival of the fungus during the winter and are sources of infection in the spring as temperatures warm and rainfull increases.

Periods of rainfull or any other source of overhead water that wets the leaves can lead to a flare-up of black spot. During wet periods, the fungus produces thousands of microscopic spores on infected leaves and canes, which can be carried to fresh leaves by wind or splashing water. Infections may continue throughout the season as long as moisture is present on the plant.

Control:

Planting resistant varieties is the most effective way to prevent black spot. Even some of these varieties may develop a low level of black spot, but will require less maintenance than those that are susceptible.

Good sanitation is imperative in an effective control program, as the fungus can survive and continue to produce sports on fallen leaves and dying canes. Dying or dead canes and fallen leaves should be removed and disposes of before new growth begins in the spring. If feasible, spotted leaves still on the plant should be removed as these are also a source of infection.

Use of drip tubes or soaker hoses is the preferred watering method. If overhead irrigation is used, watering should be done in the early morning hours to minimize leaf wetness periods.

Plant in a sunny, well-drained area where there is good air movement.

Fungicide applications in combination with good sanitation may be required. Homeowner fungicides included Spectracide Immunox, Fertilome Liquid Systemic Fungicide, Ortho Funginex, and Greenlight Fung-Away.

LATE SEASON GARDENS NEED NOT BE DULL

Think beyond pansies and mums. Other good options for fall color include perennial asters, toad lilies, goldenrod, chelone (turtlehead), Joe Pye weed, and Autumn Joy and Matrona Sedum. The salvia family really shines in the late season garden. From reds and pinks to blues and purples, there are numerous color options and plant sizes. Ornamental grasses such as fountain grass, maiden grass, zebra grass, and pampas grass are also just beginning to shine, and will continue to add textural interest in the garden throughout the winter months.

AUTUMN CROCUS

I know everybody is familiar with spring blooming crocus, but there are fall blooming crocus that will liven up your fall garden. To top that off, it blooms equally as well in sun, part sun or shade.

This wonder plant I'm talking about is colchicum (Autumn Crocus). Colchicum blooms in September and October and creates beautiful splashes of soft pink in the fall garden. For the best show, cluster at least three bulbs together in a small triangle, leaving about 6 inches between them. This will allow room for the foliage of colchicum which appears in the spring and persists until late May. The funnel shaped flowers of colchicum are not very large, topping out at about 8 inches, but for reliable, easy blooms in the fall, they are worth including in your plantings.

SOLARIZATION

Good sanitation can do wonders for your vegetable garden spot. If your vegetable garden has finished producing, now's the time to clean it up and consider solarization or, in the alternative, planting a cover crop.

If you plant your vegetable garden in the same spot year after year, diseases build up and hit the plants earlier and earlier. August is a prime time for solarization as it works best when it's hot, but September can still be a hot month, making it worth your effort. Till the garden spot as completely as you can, wet it down heavily, and cover the garden spot with black plastic, making sure the plastic and soil have firm contact. Leave it covered for at least six weeks or, alternatively, if you are done for the entire vegetable season, leave it covered all winter and remove the plastic and plant next spring.

This method works well for sites where you would like to plant wildflowers, also. After you have left the plastic on for at least six weeks, remove the plastic and sow your wildflower seeds. In northern hardiness zones 1-6, wildflowers seeded in late fall will remain in the soil and germinate the following spring. Or leave the plastic on all winter and remove in early spring and seed your wildflowers.