Mark Czarnota

Florida Betony Control

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Source(s): Mark Czarnota

Florida betony or rattlesnake weed (Stachys floridana) is a problem weed in both turf and ornamentals. Florida betony or rattlesnake weed is a “winter” perennial. Florida betony is dormant during the hot, humid summers of the South. In most of Georgia, Florida betony growth begins in early to mid fall, slows in the extreme cold of winter, and continues until late spring.

Like most plants in the mint family, betony has a square stem with opposite leaves. The leaves are up to two inches long with little teeth on them and the plant smells when crushed. Flowers of betony are usually pink and have the classic mint like structure. Unlike its relatives, it has the unique characteristic of producing glossy, white tubers that look like the rattles (buttons) of a rattlesnake, hence the name. Tubers of Florida betony can reach lengths of over 1 meter in soils with high sand contents, but they are usually one to several inches long.

In turf grass, products containing atrazine, 2,4- D, dicamba, or mecoprop provide good selective control. Other herbicides have shown some control of Florida betony on turf grass. University of Georgia research found that the following herbicides provided greater than 70% control 2 months after application: Monument (trifloxysulfuron), Manor (metsulfuron), Revolver, (foramsulfuron), and Speedzone (carfentrazone, 2,4-D ester, mecoprop, and dicamba). These herbicides are labeled only for turf grass.
In ornamentals, dichlobenil (sold under the trade name Casoron®) provides excellent control of Florida betony in some established woody ornamentals. Dichlobenil cannot be applied over every ornamental plant. Check the label to see where it can be used.

Products containing the active ingredient glyphosate (i.e. Roundup®), can be used to control this plant in ornamental beds if applied as a spray directly to betony without contacting desirable plants.

Consider using glyphosate if establishing a new ornamental planting into an area containing betony. Apply a 5% spray solution of glyphosate 1 week prior to cultivating the area. This will help reduce much of the betony population. Repeat applications to eliminate survivors will be necessary. Maintaining a good 4 to 6 inch layer of pine bark or pine straw may eventually smother the betony.

Resource(s):

Center Publication Number: 272

Poison Ivy: Leaves of Three – Let it Be!

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Source(s): Mark Czarnota, UGA Weed Specialist

Everyone who works outdoors with plants or goes hiking, camping, picnicking or other outdoor activities should be able to identify poison ivy. Failing to know it when you see it can lead to severe allergic reactions. Poison ivy and its Rhus cousins are said to cause more contact dermatitis (redness, rash, blisters and itching) in the United States than all other plants and industrial or household chemicals.

 

Poison ivy (Rhus radicans) is found mostly in moist, deciduous forests and wooded areas. Unfortunately, it’s also found on trees, fences and ornamental plantings in Georgia landscapes. A related species, poison oak (Rhus toxicodendron), may actually be a type of poison ivy. Poison ivy may grow as a small shrub or a high-climbing vine on trees, fences and buildings. Each compound leaf has three bright green, shiny leaflets.

poisonivyleaves-lrRemember the rule

The shape of the leaves and presence of hairs on the undersides vary greatly, so people may not always recognize poison ivy. The old saying, “leaflets three, let it be,” is a good rule. Poison ivy produces small flowers with five yellowish-green petals arranged on slender stalks. Its small, grayish white berries are food for more than 55 bird species.

Box elder (Acer negundo) is often confused with poison ivy. Its seedlings have three leaflets, too, but they have opposite leaves. Poison ivy leaves are alternately arranged on the stem. Virginia creeper (Parthenocissus quinquefolia) is also commonly confused with poison ivy. However, it is a harmless plant that has five leaflets growing out of one point where they are attached to the vine. Virginia creeper has blue berries. It is found growing in the home surroundings on houses, fences, trees, and in other places where poison ivy is observed.

All parts are poison

All parts of poison ivy are poisonous year-round. A toxic, oily compound (urushiol) is quickly exuded if plant tissues are broken in any way. People are exposed as they brush against the plant or touch equipment, clothes or pets that have touched it. It can even be carried in the smoke from burning the vines.

Only the oily toxin, though, can spread the rash. Symptoms usually appear in 12 to 48 hours but may not show up for days. If you think you’ve contacted poison ivy, washing your skin with cold water within 5 minutes may keep the urushiol from contacting your skin. Within the first 30 minutes, use soap and water. Consult a physician or pharmacist for the best treatment.

Can you dig it?

Digging poison ivy plants and roots can control it in small beds of landscape ornamentals. Be sure to wear watertight gloves, though. Continually clipping poison ivy at or near the ground will eventually control it. But you may have to clip it several times during the year for several years.

Chemical control

Herbicides can control poison ivy, too. But always read all label directions. Poison ivy has extensive roots, so you’ll likely have to apply herbicides many times. Glyphosate is the active ingredient in Roundup and many other products. Apply it directly to the foliage of poison ivy. It works well on warm, sunny days when plants are actively growing. It’s best when plants are flowering or fruiting, generally in early summer in Georgia.

You’ll need at least one rain-free hour after applying glyphosate to get the best results. The product can severely injure desirable plants, so don’t spray it on windy days. Use coarse sprays with large droplets to minimize drift.

Cut and spray

Where poison ivy has grown into large trees, cut the vine 2 to 3 feet above the soil. Within 24 hours, spray the leaves of the lower section (if any) with a 5-percent to 10-percent glyphosate solution (using at least a 41-percent glyphosate concentrate to make the spray solution).

If there are no leaves, paint or spray the lower stem portion with 50-50 glyphosate-water solution or undiluted glyphosate (with at least a 41-percent glyphosate concentrate.

Triclopyr (Brush-B-Gon, Brush Killer Plus) is recommended around homes, fences and nongarden areas. It’s often used to keep poison ivy and other plants from coming back after being cut. Just clip the poison ivy vine near the soil surface. Then paint the freshly cut surface with undiluted triclopyr. Don’t apply it, however, to the bark of any trees. Repeat the treatment when regrowth appears.

Resource(s): Poisonous Plants in the Landscape

Center Publication Number: 194

Dodder

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Source(s): Mark Czarnota

Dodder (Cuscuta spp.) is a parasitic weed that infects a wide range of herbaceous and woody plant material. There are approximately 12 species of dodder and each species has a different host range. Dodder is generally brought into ornamental planting via infected plant material.

Dodder

Growth Characteristics

Dodder is a rootless, leafless, parasitic flowering plant. It is in the morning glory (Convolvulaceae) family. Dodder flowers and produces seed like any other flowering plant. Seeds can remain dormant in the soils for years before germinating. Under the right conditions, dodder seed will germinate, sending up a tendril that attaches to a suitable host plant. If no suitable host is available, the plant will die within a few days. Dodder attaches itself to the host plant’s vascular system with a peg-like haustoria. Once attached, the root system of the dodder plant shrivels and the plant feeds off the host. Dodder contains no green tissues because it does not need to photosynthesize and produce its own food. The stem color of dodder is generally yellow to orange, but can also be shades of red or white. Flowers are small, white or pink, and usually born in clusters.

Host Plants

Dodder infects a wide range of plants, including plants in the Asteraceae family (chrysanthemums, marigolds and sunflowers), Fabaceae family (alfalfa, clovers, soybeans and vetches), and the Ericaceae family (azaleas and rhododendrons).

Control

Remove all plants or portions of plants infected by dodder. Ideally it should be removed before the dodder flowers and produces seed. To date, dodder cannot be controlled through a selective post emergent herbicide application. However if the host plant is killed, the dodder plant will also die. Dodder seed can be controlled with pre emergent herbicides (check label to see if these herbicides are safe to host ornamentals) and soil sterilization.

Pesticide Precautions

It is the responsibility of the pesticide user to observe all directions, restrictions and precautions on pesticide labels. It is dangerous, wasteful and illegal to do otherwise. Store all pesticides in original containers with labels intact and behind locked doors. Use pesticides at correct label dosage and intervals to avoid illegal residues or injury to plants and animals. Use pesticides carefully to avoid drift or contamination of non- target areas. Surplus pesticides and containers should be disposed of in accordance with label instructions so contamination of water and other hazards will not result. Follow directions on the pesticide label regarding restrictions as required by State or Federal Laws and Regulations. Avoid any action that may threaten an endangered species or its habitat.

KEEP PESTICIDES OUT OF THE REACH OF CHILDREN!

Center Publication Number: 216