Five Invasive Weeds You Do Not Want!

What makes a weed a weed is whether or not it’s wanted in your landscape. All the weeds on this list have positive and beneficial attributes that if it weren’t for their stubborn invasive habits would make them very desirable. Having had to deal with all of them in my own yard or on land around the South, I can testify that they are all royal pains which you do not want in your yard.

Two cautions to keep in mind: First, when considering chemical control, local laws affecting herbicide use must be observed. Second, there are a lot of folk medicine uses mentioned here. I’m not into herbal remedies myself, so before you go poisoning yourself, do some more research, ok?

1. Chamberbitter

Invasive weed

Latin and Common Names: Phyllanthus urinaria, commonly called niruri (Spanish for stone break), little mimosa, gripe weed, shatter stone, or leaf flower.

What it looks like: Chamberbitter is more of a tropical plant that loves hot weather and can tolerate drought conditions. It is a member of the Euphorbiaceae family and has the sticky, milky sap like many of the Spurge weeds we deal with in the landscape.

What it’s good for: In Asia and South America, where it’s even more common than in my backyard, it’s used as an herbal cure for kidney stones. Thus the “break stone” nickname.

Why it’s a weed: It’s a very hardy little plant that grows fast, is drought tolerant, flowers and produces seed in just two weeks. The nail in the coffin is the prolific amount of seed it produces. Worst of all, the seed capsules explode when the plant is disturbed and hurl seed in many directions away from the plant thus spreading it over a larger area. And since it needs very warm soil to germinate, most of the early spring applications of pre-emergents are ineffective once May rolls around and Chamberbitter is germinating.

How to fight it: Unfortunately, many of the more common pre-emergent herbicides we use in the spring are not effective on Chamberbitter. We can control it by being very persistent in our efforts and then by taking a multi-prong approach of implementing Mechanical controls, Cultural controls and lastly Chemical controls to help alleviate the problem. This is a very pervasive weed that can spread quickly so it will take all the tools at our disposal to get it under control.

Mechanical control means carefully and gently pulling the weeds by hand out of infested yards and beds. The yellowish ball like fruits develop under the leaves. The good news is that they will pull easily if the soil is wet but tend to break off if the soil is dry. Since they produce so much seed very quickly, do not under any circumstances put these in your compost bin.

Cultural controls begin with proper mulching. Weed seeds need light to germinate so a good one to three inch layer of mulch over bare soil will help to keep weed seeds from germinating. However, if new weeds emerge from within the beds and then drop fresh seeds, they can grow on top of the mulch.   Also if Chamberbitter is in turf areas then mowing regularly will keep weeds from setting flowers and thus seeds. The different color and texture of Chamberbitter will be obvious in most yards.

Chemical controls start as the final option but can easily become your crutch. With herbicides we have two classes of products to use. One is a Pre-emergent herbicide that is applied before we see the weeds growing and they work by keeping the weed seeds from germinating. This is a great way to control weeds but timing is critical to insure success. According to the Georgia Extension Service, pre-emergence herbicides that contain atrazine (Purge) on centipede lawns and isoxaben on all turfgrasses give good results when applied in early May. Apply isoxaben pre-emergent herbicide in late April and again in mid-June to areas where you will not be planting seeds for anything else. As with every herbicide, read the label and follow it exactly.

The other type is post-emergent herbicide or one that we apply directly to the growing weed for control. Since Chamberbitter is so difficult to control you may have to use both types to get the weed population down to manageable levels. No herbicide will knock it out quickly and permanently. Repeated applications of an herbicide that contains 2,4-D (Weed-B-Gon, Weed Stop, Wipe-Out, etc) will control it, particularly if you start spraying when the weed is young.

Whatever you do, don’t let this little pest become established in your yard. Taking a couple of weeks off from control just gives this plant a new lease on life and your labor.

2. Chinese Privet

Chinese privet

Latin and common names: Ligustrum sinense, Chinese privet, common privet.

What it looks like: Ligustrum spp. are perennial shrubs that can grow up to 16 feet in height. Ligustrum bark is tan to gray in color with a smooth texture. Leaves are elliptic to oval in shape, oppositely arranged on twigs. Flowers have both male and female parts. Each flower has petals fused into a tube with four separate lobes. Flowers are borne on small stem-like growths on short lateral branches on the end of the twig. The oblong, blue/black fruit is a drupe containing 1 to 4 seeds. Fruit clusters persist through the winter. Mature trees can produce hundreds of fruit.

Glossy privet is a large shrub or tree that grows to 30 feet in height, with spreading branches. Leaves are oval to somewhat elongated and 3 to 5 inches long.

Chinese privet is smaller than glossy privet, growing to only 20 feet in height. Leaves are elliptic to somewhat oblong, and 1 to 3 inches long.

What it’s good for: Chinese privet is used in traditional herbal medicine. The boiling of privet leaves or bark to a paste which helps to treat diarrhea, stomach ulcers, chronic bowel problems, chapped lips, sore mouths and throats, and a wash for skin problems. Privet leaves and bark have bitter properties that make a useful tea for improving appetite and digestion in chemotherapy patients.

Some species produce a fruit, which is mildly toxic to humans. Symptoms from eating privet fruit include nausea, headache, abdominal pain, vomiting, diarrhea, weakness, low blood pressure, and low body temperature.

Why it’s a weed: In 1852, privet was introduced to the United States for use as an ornamental shrub and is still commonly used as a hedge. Because of its ability to tolerate air pollution and other poor environmental conditions, it was regarded as a great landscape plant and planted extensively. Unfortunately, as time passed its invasive characteristics were discovered. Establishment of privet in many natural areas of the south and southwest has occurred through its escape from cultivation. Chinese privet is a Category I (that’s bad) species that disrupts native plant communities.

The aggressive nature of privets allows for the formation of dense thickets that out-competes desirable plants. The amount of seed produced by privet is another mechanism for its prolonged survival. Even though privet is still used in the landscape and available for purchase at garden centers and online distributors, it is an invasive weed and should be treated as such.

How to fight it: You can’t control it, you can only eradicate it.

If you have a large infestation, I recommended you contact your local extension agent and/or county weed specialist for control measures pertinent to your area. For larger natural areas where the use of chemical herbicides is inadvisable, enlisting numerous helpers to mechanically remove Chinese privet may be required. Using heavy equipment for large-scale removal may be appropriate in some locations, but the negative effects of soil disturbance and the potential for erosion need to be considered.

For small areas and for relatively small plants, hand removal is effective. Digging tools are useful for removing underground parts. Broken root fragments need to be removed because of their ability to re-sprout. Repeated mowing and cutting will control the spread of privet, but will not eradicate it. For such treatment, stems should be cut as close to the ground as possible. Mechanical removal is especially effective in the early stages of an invasion when the numbers of plants are relatively small.

Herbicide treatments properly applied can selectively remove invasive species with minimal soil disturbance. Even slight soil disturbance may offer opportunities for re-invasion. Some may damage non-target species. Herbicides will behave differently in different environments and under different conditions. For example, they may degrade more slowly in wetter, more anaerobic soils or move downward in sandier soils. A careful monitoring program is essential for evaluating herbicide use.

Effective control of Chinese privet with glyphosate herbicides such as Round=Up, stating that foliage treatment is best for actively growing plants is useful. Foliar spray methods should be used only where risk to non-target species is minimal. A 2% solution of glyphosate or 2% triclopyr with a one-half percent of non-ionic surfactant is reportedly effective.

Fire is also used as a herbicidal pretreatment. In the spring following the fall and winter burns, foliage application of glyphosate damage or kills a majority of the Chinese privet shoots. Burning helps foliar application of herbicide by reducing biomass but it does not increase the effectiveness of the herbicide compared to the unburned controls.

3. Dandelion


Latin and common names: Lentodon taraxacum. Some common names include bitterwort, blow-ball, puffball, cankerwort, clockflower, Irish daisy, lion’s tooth, priest’s crown, swine’s snout, telltime, yellow gowan, cankerwort, doon-head-clock, witch’s gowan, milk witch, white endive, wild endive, Irish daisy, monks-head, priest’s-crown, butter flower, puff-ball and faceclock. Piss-in-bed and wet-a-bed refers to the strong diuretic effect of the plant’s roots. In various northeastern Italian dialects, the plant is known as pisacan (“dog pisses”), because they are found at the side of pavements.

What it looks like: Dandelion is defined by its basal leaves with jagged edges, hollow stems that are leafless and terminate in very small, yellow flowers called florets which cluster to form a composite flower head, and fluffy white seed heads. At maturity, all plant parts exude a milky juice if cut. Reproduction is by wind-blown seeds. Plants also regenerate from root fragments.

What it’s good for: Dandelion is an herb. People use the above ground parts and root to make folk medicine. The reason it works is because Dandelions contain chemicals that may increase urine production and decrease swelling (inflammation).

Dandelion is used for many conditions, but so far, there isn’t enough scientific evidence to determine whether or not it is effective for any of them. Dandelion is used for loss of appetite, upset stomach, intestinal gas, joint pain, muscle aches, excema, and bruises. Dandelion is also used to increase urine production and as a laxative to increase bowel movement. It is also used as skin toner, blood tonic, and digestive tonic. Some people use dandelion to treat infection, especially viral infections, and cancer.

In foods, dandelion is used for salad greens, and in soups, wine, and teas. The roasted root is used as a coffee substitute.

Why it’s a weed: The species is considered a nuisance in residential and recreational lawns. It is also an important weed in agriculture and causes significant economic damage because of its infestation in many crops worldwide.

Dandelions produce seeds asexually, where the seeds are produced without pollination. In addition to reproducing by seed, dandelions reproduce by vegetative structures such as fleshy taproots.

How to fight it: In a normal yard or garden, a combination of methods will become routine. Prevention by mowing high and often encourage a thick grass cover with fewer weak spots. Use pre-emergents like Preen applied at the first sign of yellow flowers or chemicals like Weed-B-Gone and Roundup applied directly to the plant. Mechanical solutions don’t work as well since any piece of the taproot that remains in the ground will quickly re-emerge into a new weed in your yard.

4. Annual Bluegrass

Annual Bluegrass

Latin and common names: Poa Annua Annual Bluegrass, poa, annual meadow grass.

What it looks like: Annual bluegrass is a low growing cool-season grass in the family Poaceae. Annual bluegrass leaf blade tips are prow-shaped, and leaves tend to be crinkled at the midsection. Mature plants grow in dense tufts, 3 to 12 inches tall with roots at the lower nodes. The flowering structure is a terminal spreading stem-like structure that varies between 1 and 4 inches in length. The root system is fairly shallow and weak, requiring moisture from rain or frequent irrigation

What it’s good for: Poa is Greek for “fodder”. It is one of the sweetest grasses for green fodder, but less useful than hay. Cattle love it!

Why it’s a weed: Annual bluegrass is a major weed in turf where it provides a weak sod that leads to poor footing in athletic fields and golf courses. Annual bluegrass is also weedy in alfalfa, grass seed, small grain, and potato. It re-seeds itself prolifically! Annual bluegrass is outwardly attractive in the winter but just wait until spring. The thick mat of bluegrass chokes out the better turf underneath. When hot weather comes, the bluegrass dies, leaving a large bare spot and a legacy of thousands of seed for next fall.

How to fight it: The best control is to apply a pre-emergent in the fall. In this area, that’s mid-September. Products that contain benefin, bensulide, oryzalin, pendimethalin, dithiopyr, or prodiamine provide good, if not perfect, results. The problem is these are also good at stopping the new fescue grass seeds usually spread in the same season.

5. Kudzu


Latin and common names: Pueraria. Foot-a-night vine, vine-that-ate-the-South, Ko-hemp, Fen Ke, Fenge, Gange, Ge Gen, Gegen, Indian Kudzu, Japanese Arrowroot, Kakkon, Mealy Kudzu, White Indian Kudzu, Yege.

What it looks like: Kudzu is a deciduous yellow-green to gray woody vine that may reach a thickness of 10” in diameter. The long, bristly vines have large leaves that can grow up to 6” long. These vines drop their leaves in the winter months. Abandoned buildings, cars, and other items are quickly covered by this fast growing vine. Kudzu leaves are alternate and pinnately compound, with three leaflets. Leaves are generally dark green but some can be lighter.

What it’s good for: It makes excellent material for basket weaving, or you can make flour from the roots and add the leaves to recipes. Kudzu’s root, flower, and leaf are used to make medicine. It has been used in Chinese medicine since at least 200 BC.

Today, kudzu is used to treat alcoholism and to reduce symptoms of alcohol hangover, including headache, upset stomach, dizziness, and vomiting. Kudzu is also used for heart and circulatory problems, including high blood pressure, irregular heartbeat, and chest pain; for upper respiratory problems including sinus infections, the common cold, hay fever, flu, and swine flu; and for skin problems, including skin rash, itchiness, and psoriasis.

Why it’s a weed: Kudzu was originally introduced in 1876 at the Centennial Exposition in Philadelphia as an ornamental, promoted in the 1930s by the U.S. Soil Conservation Service for erosion control. By the early 1950s, it was no longer advocated by the U.S. Department of Agriculture. It officially was acknowledged as a weed in 1972. Today it’s illegal to introduce Kudzu in any area not already infested with it.

Kudzu forms large impenetrable masses, growing over woody vegetation and completely engulfing unwooded areas. It can completely envelop a tree, killing it by shutting out all light. It flowers in late summer and early fall, with high production of seeds, which are dispersed by mammals and birds.

How to fight it: Ideally, simply pulling out the heavy vines would prevent the kudzu from returning. However, you still need to kill each of the rooted stems at their crowns.

How to get rid of kudzu for certain in one season? Mowing or cutting back the vegetation to the ground provides the first step in removal. Then it’s time to bring out the big guns in the form of chemical herbicides. A brush killer with triplocyr or 2,4D with dicamba may be sufficient to kill the plant after repeated applications. This will be a several season battle, as the plant may return the next growing period with a vengeance.

If chemical applications are not your thing, you’ll have to use only mechanical pulling and cutting, and live with the results. Remember, kudzu vine control is a battle you will need to be persistent on unless you want kudzu salad every day of your life.

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