The Daily Southerner, Tarboro, NC

July 27, 2012

Ask A Master Gardener

FOR THE DAILY SOUTHERNER
Buddy Hooks

TARBORO — “Ask A Master Gardener” helps our readers to solve common problems concerning horticulture, gardening, and pest management through a trained and supervised staff of Extension Master Gardener volunteers.  The Extension Master Gardener program is an educational program designed to enhance public education in consumer horticulture.

Submit your questions by email to askemgv@gmail.com.  Or, you can call the local Extension Center at 252-641-7815 and tell them you have a question for a master gardener. You ask the questions and a local Master Gardener will return your call with a solution to your problem and share it with our readers.

Answers reflect research collected from land grant universities (NCSU or NCA&T) and through a national extension website, www.extension.org.  



Q. Susan S. - (Northwoods Country Road) asks - How do I control common lespedeza (weed) in my centipede?

A. -- Lespedeza is a dark green, wiry summer annual with trifoliate leaves. Several wide-spreading prostrate branches come from the slender taproot. It grows close to the ground and seldom is cut by a mower. It is a very common summer weed, choking out thin turf. Hairs grow downward on the stem. Leaves are composed of three leaflets. Stipules are light to reddish brown. Small single flowers arise from the leaf axils on most of the nodes of the main stems and are pink or purple.



CULTURAL CONTROL

Maintain a dense, actively growing turf through proper mowing, fertilizing, and watering practices. Mow at the proper height for your selected adapted turfgrass. Coring and traffic control reduce compaction and encourage desirable turfgrass competition. It is best to control this summer annual broadleaf weed in late spring or early summer because it is easier to control at this time and the turf will have a greater chance of recovering the areas previously occupied by weeds.



CHEMICAL CONTROL

Common lespedeza is a difficult-to-control summer annual broadleaf weed that can be effectively controlled post-emergence in the spring with products containing fluroxypyr (e.g., Spotlight, Escalade 2) or triclopyr (e.g., Turflon Ester). Manor (metsulfuron) will also provide good to excellent control. Check with your local garden center for availability.

For more details, visit: http://www.turffiles.ncsu.edu/Weeds/Lespedeza_Common.aspx

Q. Bob F. (Tarboro) asks- What should I be doing with my centipede during July & August?

A. Mowing -Mow lawn at 1 inch. Mow before grass gets above 1 1/2 inches tall.

Fertilization -Fertilize with 1/2 pound of nitrogen per 1,000 sq. ft. (once a year) in mid-June using a high potassium fertilizer (e.g., 5-5-15, 6-6-12, 8-8-24). An additional fertilization in August may enhance performance in coastal locations. Fertilizers without phosphorus (e.g., 15-0-14, 8-0-24) are preferred if soils exhibit moderate-to-high levels of phosphorus. Yellow appearance may indicate an iron deficiency. Spray iron (ferrous) sulfate (2 ounces in water per 1,000 sq. ft.) or a chelated iron source to enhance color as needed. Always follow label directions.

To determine amount of product required to apply 1/2 pound of nitrogen per 1,000 sq. ft., divide 50 by the FIRST number on the fertilizer bag. Example: A 5-5-15 fertilizer. Dividing 50 by 5 = 10 pounds of product to be applied per 1,000 sq. ft. for 1/2 pound of nitrogen.

Watering -Water to prevent drought stress. About 1 inch of water per application each week is needed for growing centipedegrass. Sandy soils often require more frequent watering; i.e., l/2 inch of water every third day.

Weed Control -Apply post-emergent herbicides as needed for control of summer annual and perennial broadleaf weeds, such as knotweed, spurge, lespedeza, etc. Centipedegrass is sensitive to certain herbicides (e.g., 2,4-D, MSMA), so follow label directions and use with caution. Do not apply herbicides unless grass and weeds are actively growing and lawn is not suffering from drought stress.

Insect Control -Check for white grubs and control if necessary.

Disease Control -Have soil assayed if nematode damage is suspected. Contact your county Extension Center for assistance.

This site provides full calendar year for several types of turfgrass: http://www.turffiles.ncsu.edu/Maintenance_Calendars.aspx#000019



Q. David B. -(Princeville) asks- Why are there brown rotten spots on the bottoms of my watermelon?

A. Sounds like Blossom-end rot of watermelons and it’s very similar to the same problem that occurs on tomatoes and primarily is related to a soil-moisture imbalance. Mulching and occasional watering to prevent moisture stress during dry periods will help prevent blossom-end rot. If the problem occurs, prune off all the affected fruits.

This problem can also be attributed to lack of calcium in the developing fruit. This may be due to a lack of calcium uptake from the soil or to extreme fluctuations in water supply. Incidence of blossom-end rot is also increased where there is a low ratio of calcium to certain other nutrients such as potassium and nitrogen. Although the most desirable calcium levels for preventing blossom-end rot have not been determined, the application of lime to soils known to be low in calcium has helped to prevent the disease. Soil should be limed according to recommendations of soil analysis report, usually to pH 6.5-6.8 if one is obtained.

More details can be found at :http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/vg19.htm

Q. Bob F. - (Tarboro) asks- What is the insecticide "Bt" (Bacillus thuringiensis) and what insects does it control?



A. It’s a Microbial Insecticide which is especially valuable because their toxicity to non-target animals and humans is extremely low. Compared to other commonly used insecticides, they are safe for both the pesticide user and consumers of treated crops. The safety offered by microbial insecticides is their greatest strength, and most microbial insecticides do not directly affect beneficial insects (including predators or parasites of pests) in treated areas.

Look for these common trade names and commercial products at your local garden center: Dipel®,

Javelin®, Thuricide®, Worm Attack®, Caterpillar Killer®, Bactospeine®, and SOK-Bt®, but

many small companies sell similar products under a variety of trade names.

They are used to control many common leaf-feeding caterpillars, including caterpillar pests on vegetables (especially the "worms" that attack cabbage, broccoli, cauliflower, and Brussels sprouts), bagworms and tent caterpillars on trees and shrubs, larvae of the gypsy moth and other forest caterpillars, and European corn borer larvae in field corn.  One product with a very specific target is Certan®, formulated from Bacillus thuringiensis var. aizawai, and used exclusively for the control of wax moth larvae in honeybee hives. For even more details, visit: http://miami-dade.ifas.ufl.edu/pdfs/fyn/bt.pdf



Q. Rick F. - (Howard Ave. Extension) asks- Why aren't my Crape Myrtles flowering well?

Not Enough Sunlight: For superior flowering, they require full sun, six- eight hours per day. They will grow in a shaded environment, but will not be as full, and flowering will be diminished or non-existent.

Insufficient Water: Crapemyrtles are quite drought tolerant once they have become established; however, supplemental watering during dry spells will provide better growth and flowering. Using a three to four inch layer of mulch out to the drip line of the tree will help modify the soil temperature, and will help conserve soil moisture.

Low Fertility: Crapemyrtles benefit from an application of a complete fertilizer in early spring to produce enough energy for growth and flower production

Severe Pruning: Heavily pruned crapemyrtles will put most of their energy into regrowing limbs and leaves and less energy will go into flower production



“Ask A Master Gardener” also wants to include your “tried and true” gardening tips and techniques and snapshots from your garden; please share in an email to askemgv@gmail.com or by writing to “Ask A Master Gardener”, c/o The Daily Southerner, P.O. Box 1199, Tarboro, NC 27886.