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Weeds - Master Reference List


Aster, Roadside (Aster exilis) Annual broad-leafed wildflower with white or light blue flowers in fall. Control by improving the moisture level and fertility of the soil.

 
Bermudagrass (Cynodon sactylon)  One of the worst weeds of all when you don’t want it. Roundup will kill it but is far more toxic than advertised and should no longer be used. Physical removal is best. In beds it can be controlled by covering the area with ½” compost followed by 5 layers of newspaper or one later of cardboard and then shredded mulch. Repeated vinegar sprays will also kill it.
 
Bindweed (Convolvulus arvensis)  Introduced from Eurasia. Ranked among the dozen worst perennial weeds in the world. Roots go 6’ deep, can be dormant in the soil for 30 years and still germinate. Also called wild morning glory. Control by increasing organic matter in the soil and keep removing all pieces of the plant from the soil.
 
Black Medic (Medicago lupulina)  Annual or sometimes perennial; stems are hairy and branch at the base. Branches are prostrate and spreading. Flowers are small and yellow, in short, globe heads. Controls include soil and turf improvement along with hand removal and/or spot spraying with one of the vinegar or fatty acid products.
 
Bluegrass, Annual (Poa annua) Small cool season grass is a particularly serious weed problem in closely mowed areas. It begins to emerge in late summer and early fall when night temperatures are in the 60’s and moisture is present. Annual bluegrass seeds continue to germinate through the fall, winter and spring making chemical control more difficult. Favored by moist soil conditions and cool temperatures. It has a strong competitive advantage over warm season grasses from fall through spring. Annual bluegrass is greatly reduced by taller mowing heights and limited use of water. Seed heads form in late fall and winter, but seed head development is greatest in the spring and early summer. Control with pre and post emergence herbicides like corn gluten meal. 
 
Brambles (Rubus spp) Various berry plants with sharp thorns. These woody plants spread to form dense masses. Control by pulling up. Spray re-growth with vinegar-based herbicide.
 
Bull Nettle (Cnidoscolus texanus) Perennial problem weed in deep, sandy soils with low fertility. Leaves and stems are covered with stinging hairs. Huge underground storage tubers. Control by increasing organic matter and in the soil.
 
Bur Clover (Medicago hispida) Very low-growing annual cool-weather legume. Small yellow pea like flowers. Seeds contained in a soft-spined bur. Control by increasing soil health. It is similar in appearance to black medic.
 
Canada Thistle (Circium arvense) Perennial weed, 1 ½-4’ in height. Very difficult to control because of its deep root system. Control by mowing when plant is in full bloom. Root system is exhausted when it is the prettiest.
 
Chickweed (Stellaria media) Common chickweed is a cool season annual that is a low growing, succulent weed that often spreads out in extensive mats. It may survive summer in moist, shady, cool areas. Seed leaves have prominent mid veins and are about four times as long as broad, tapering to a point at the tip. True leaves are broader, opposite, and yellow green. Flowers are small but showy with five deeply cut white petals. Control by mulching beds and improving turf quality. Easy to remove by hand.
 
Clover, White (Trifolium repens) Perennial. Round flower heads consisting of 20-40 white to pinkish-white florets on long stems. Creeping stems up to 15’ long with dark green three-part leaves. Roots at the joints of the stems. Deeply rooted. Likes cool weather and clay soils. Evergreen when irrigated in the summer. Plant in September or October for best results. Ground cover, cover crop, turf plant. One of the nation’s most important pasture legumes. Great for soil building because of its deep roots and nitrogen fixing ability. Usually considered a weed, but it shouldn’t be. It’s prettier than grass. This and all other clovers can be controlled with the Agralawn Crabgrass Killer product.
 
Cocklebur (Xanthium strumarium) Tall, bushy, annual weed with prickly seeds and sandpaper-like leaves. Grows in poor quality soil where excess phosphorous is available to plants.
 
Crabgrass (Digitaria sanquinalis) Crabgrass is the major annual weed infesting many home lawns. It is an annual weed germinating in April, setting seed in August and dying with the first frost of fall. Crabgrass has tremendous survival reproductive capabilities. A few crabgrass plants in your lawn are acceptable. The most effective way to control crabgrass is to create a dense, healthy turf. Pre-emergence herbicides prevent emergence of crabgrass plants in the spring. These products must be applied prior to crabgrass germination that could occur as early as April 1st. Post-emergence herbicides control crabgrass after it has emerged. These products are most effective on small crabgrass. It is better to simply tolerate the crabgrass until it dies with the first frost. However, it can be killed by spot-spraying the vinegar-based herbicides. The Agralawn Crabgrass control product is also effective.
 
Creeping Charlie (Glechoma hederacea) Also called gill ivy and ground ivy, this is a most carefree but invasive groundcover. It has rounded leaves, grows easily in any soil in shade. Small purple flowers in spring. If considered a weed, it is easy to kill out with any of the organic herbicides.

Crow Poison Other common names:  false garlic, wild garlic, yellow false garlic Nothoscordum bivalve (noth-oh-SKOR-dum  by-VAL-vee) Full sun to partial shade. Height: 6-12 in. Crow poison looks much like wild onion but does not have the onion smell. Early spring and fall flower. It grows from a bulb and looks much like the wild onion, but has fewer and larger flowers on long stems and lacks the onion odor. The leaves are all at the base of the plant, about 1/8 inch wide and 4–15 inches. It is an upright perennial with a white flower about 1 inch in diameter and consists of six petals. This plant is mildly poisonous and should not be tasted. Wild onion that looks almost the same has a strong onion fragrance when crushed; crow poison does not. Control with soil improvement and organic herbicides.
 
Dallisgrass (Paspalum dilatatum) Long-lived, warm season, deep-rooted high-successional perennial bunch grass. Forms low flat clumps with dead looking centers and tall fast-growing seed heads. It is one of the most troublesome weeds in lawns. Begins growth in very early spring and prefers warm, moist areas and high-cut lawns. Tolerate almost any type of soil, reproducing by seeds and rhizomes (underground stems). Has long coarse-textured leaves ½ inch wide and 4-10 inches long. Stems 2-6 inches long radiate from the center of the plant in a star pattern. Seeds are produced on 3-5 finger-like segments that grow from the top of these stems from May to October. Seed stalks grow tall and are unattractive in lawns. It grows most vigorously in warm summer weather, but can remain green in mild winters. Control with vinegar based herbicides and physical removal followed by an application of compost. Best control is usually to dig out and fill depressions with compost.
 
Dandelion (Taraxacum officinale) Perennial with yellow flowers and powder-puff seed heads. Lettuce-like foliage, deep taproot. All parts of the plant are edible and health giving. Flowers can be used in cookies and wine, young foliage in salads, the root in tea. The aggressive root system brings minerals from the subsoil up to the surface. Aeration and proper use of organic fertilizers will greatly reduce the population. Kill, if necessary by spraying with full strength vinegar or removing manually. It is hard to control with the organic pre-emergent corn gluten meal because it tends to germinate over a long period of time starting in very early fall or late summer with any cool spells. 
 
Dichondra (Dichondra micrantha) I like this plant more than grass in certain situations. Perennial lawn plant or ground cover. Very low growing, spreads by runners. Foliage looks like tiny lily pads. Likes partial to heavy shade and moist soil. Excellent between stepping stones. Sometimes used as turf. Many people don’t understand that dichondra is a beautiful ground cover instead of a noxious weed to be sprayed with toxic herbicides. Can be killed with broadleaf herbicides, but why? If you don’t like it, let the soil dry out more between watering. Sometimes sold as Dichondra carolinensis or Dichondra repens. Dichondra is often confused with dollarweed which has larger, more vertical growing and shiny leaves. Both plants can be controlled with Agralawn Crabgrass Killer.
 
Dodder (Cuscuta spp.) This annual weed that reproduces by seed starts as an independent plant but establishes a parasitic relationship with the host crop. At this point it has no chlorophyll and looks like yellow string. Control it long term by balancing the minerals in the soil. It can be killed quickly with hydrogen peroxide, fatty acid or vinegar products.
 
Dollarweed (Hydrocotyle spp.) Also known by some as pennywort, it is a warm-season perennial weed. Its common name, dollarweed, comes from the silver- dollar-shaped leaves that are round, bright green, fleshy and look like miniature lily pads measuring 1-2” in diameter with a scalloped edge. It has a low-growing habit and spreads by seeds, rhizomes and tubers. Dollarweed is often confused with dichondra. One way to distinguish the two is by looking at the placement of the leaf stem. Dollarweed has a stem located in the center of the leaf while dichondra’s stem is located at the edge. Dollarweed is a water-loving plant that can float. The presence of dollarweed indicates that there is excessive moisture in the area. Research at the University of Florida demonstrated a reduction in dollarweed just by reducing irrigation frequency.
 
Fairy Rings, Toadstools, Mushrooms - Mushrooms in lawns are common especially during rainy weather. They live off decaying organic matter in the soil, often decaying tree roots and are not harmful to the lawn. They will naturally disappear with age or they may be collected and composted, knocked down with a rake or hoe or mowed over with mower. Mushrooms should never be collected and eaten unless you are expert in their identification. To many gardeners, poisonous mushrooms can look very similar to edible ones. Don’t take a chance. Fairy rings are the fruiting bodies of fungi growing on decaying organic matter. The white caps look like golf balls when young but expand to 4’-8” in diameter at maturity. Usually appear in lawns in summer after rainy periods. Caps are white at first, then turn gray-green and have distinctive green spores, reddish brown “scales” on the cap and a ring on the smooth stalk. Fairy rings usually grow in soil where wood of dead roots, lumber or old stumps are decaying. These organisms are toxic and known for their tendency to collect heavy metals from the air and soil.

Field Madder (Sherardia arvensis) Other common names: spurwort, herb sherard, field-madder. This widespread, introduced wildflower/weed is a prostrate growing winter annual that lasts well into the spring. It forms mats in the turf. The leaves are pointed, elliptical and form in whorls around the stem that is square. It spreads by seeds produced in flowers at the tip of the stems. The flowers are pink to lavender in color and occur in the early spring. Field madder is found in the Piedmont region of the southern states. 
 
Field madder thrives in thin turf and is not controlled by mowing, but mowing will at least prevent flower formation and additional seed production. If you consider this plant a weed, thicken the turf with organic techniques and products. If you must kill it, any of the organic herbicides will work.

Goathead or puncture vine (Tribulus terrestris) Hairy, low-growing annual with a taproot and several stems forming a rosette. Has yellow flowers and burs that will puncture tires. Same basic control as for grassburs. Here is an excellent website specifically about this troublesome weed. http://www.goatheads.com
 
Goosegrass (Eleusine indica) Goosegrass, also called wiregrass, is an annual weed that grows as a compressed plant in turf and reproduces by seed in unhealthy soil. It appears as a silvery mat forming a pale green clump with a low rosette and flattened stems. Flower stalks are short, stout, and compressed. Seed heads are somewhat similar to those of dallisgrass, but short and stiff. Normally found in compacted areas or areas of heavy wear. Produces seed even under close mowing. Very similar to crabgrass. Control with healthy soil and spraying vinegar-based products. 
 
Grassbur (Cenchrus echinatus) Also called sand spur, sticker bur and field sandbur, it is a summer annual grassy weed adapted to dry, sandy soils but can be found growing in other types of soils as well. Small black seeds in the sharp, spiny burs generally start germinating in late spring and will continue to germinate until late summer or early fall months. Plant will continue to grow until the first hard frost or freeze occurs in the fall. Generally not a problem in well maintained turfgrass areas. Apply compost, corn gluten meal, lava sand and the entire organic program for best control.
 
Henbit (Lamium amplexicaule) Winter annual that reproduces by seed and rooting stems. Henbit stems droop and then turn upright to grow to 16 inches tall. They may root where they touch the ground. They are square, green to purplish and smooth or hairy. The roots are fibrous. ½ to 1 inch long leaves. Henbit flowers are tubular, pink to red to purple. Henbit is often found growing in moist, fertile soils. To control henbit without herbicides, maintain density and health of established turf. Small populations can be hoed or hand pulled or sprayed with vinegar based organic herbicides. Pre-emergence herbicides (corn gluten meal) should be applied in late summer before germination. Mowing usually takes it out because it is taller than the lawngrasses. I actually consider this plant a wildflower.

Hoary Bowlesia Bowlesia incana Apiaceae (Carrot or parsley family) common weed native to South America and the southeastern and southwestern United States as far north as Oregon. It grows in many types of habitat. This is a small annual herb growing thin, spreading stems. The leaves are borne on long petioles and have multi-lobed rounded or kidney-shaped blades. The leaves are coated in fine white hairs. The inflorescences of yellow-green flowers appear in the leaf axils. Tiny fruit. Easy to hand remove, spot spray kill with vinegar or other organic herbicides.
 
Johnsongrass (Sorghum halepense) One of the most troublesome of perennial grasses. It reproduces from underground stems and seeds. Grows in spreading, leafy patches that may be as tall as 6 to 7 feet. Leaves have a prominent whitish midvein, which snap readily when folded over. The flower head is large, open, well branched, and often reddish tinged. Underground stems are thick, fleshy, and segmented. Roots and shoots can rise from each segment. Control by mowing regularly. It can’t stand the pressure. Johnsongrass has become resistant to the herbicide glyphosate (Roundup). Johnsongrass is the latest in a string of resistant weeds that calls into question the widespread use of genetically engineered (GE) herbicide-tolerant crops. 

Lichen This isn’t a weed or a plant problem in any way but many people worry about it. It is a growth seen on rocks and the trunks of trees that is actually two plants. Commonly growing in flat greenish, gray, brown, yellow or black patches, lichen consists of algae and fungi. They live together in a symbiotic relationship. The fungi absorb and conserve moisture and provides shelter. The algae conduct photosynthesis, grow and provide protein for the fungi. No treatment or worry needed.
 
Mistletoe Plant parasite that primarily attaches to limbs and trunks of low quality and/or stressed trees, such as Arizona ashhackberrybois d’ arc, locust, box elder, and weak elms and ashes. Remove by cutting infected limbs off the tree. If that can’t be done, notch into the limb to remove the rooting structure of the mistletoe and paint with black pruning paint to prevent re-sprout. There are no magic chemical or organic sprays that work on this parasite. Keeping the soil and trees healthy is the best preventative. Applying dry molasses to the root zone of infected trees has been reported to rid trees of mistletoe. The application of the entire Sick Tree Treatment will work in most all cases.
 
Nutgrass (Cyperus esculentus and Cyperus rotundus) Nutsedge also called purple or yellow nutgrass are perennial sedges introduced from Eurasia.  They spread by seeds, nutlets and creeping tendrils.  They like wet, anaerobic soils and that is a key to control. They are perennial pests in lawns and gardens. Erect, single, triangular stems have narrow, grass-like, yellow-green leaves. Leaves point outward in 3 directions. Booms in late summer to early fall. Seed heads are yellow-brown. Plant tops die back in the fall, leaving underground tubers to over winter in the soil and repeat the cycle the following year. Nutgrass reproduces by seeds as well as tubers, which are generally the size of popcorn kernels. Weeds sprout in late spring and early summer. A single tuber of yellow nutsedge is capable of producing 146 tubers within 14 weeks following planting and can infest an area 6 ½ feet in diameter. We used to say that there's no good organic or toxic chemical solution for nutgrass.   On the toxic chemical side, that’s true. The commonly recommended chemicals are Image and Manage. Most everyone in the landscape industry agrees that Image doesn't work on one of the most common species. Manage works better but will severely damage or kill your trees. 
 
We have had luck and others have reported success by killing nutgrass with kindness. Mow, clip or pull as often as you can and apply a heavier than normal application of dry molasses. Use about 20 lbs. per 1000 sq. ft. and repeat in two weeks. The mixed products that contain molasses and cornmeal will also help. The idea is to stimulate a furious level of biological activity aimed at rotting the crowns of the weeds.
 
Another remedy is to remove the weed physically with mechanical devices. In beds cover the weeds with newspaper and mulch. Spot spray with the vinegar herbicide formula or other organic herbicides such as BioSafe. For turf, overseed problem areas with ryegrass in the fall. Applying corn gluten meal in the spring at 20 pounds per 1,000 square feet prior to seed germination is also helpful to prevent additional seed from germinating. 
 
An important point to remember is that nutgrass (nutsedge) grows primarily in wet, anaerobic soil. Try applying hydrogen peroxide, the 3% kind at the drug store, full strength to the problem areas. Also let the areas dry out better between waterings, improve soil health, improve drainage and help the soil to drain better. The best control appears to be molasses, believe it or not. Drench problem spots with liquid horticultural molasses at ¼ to ½ cup per gallon of water. Start with about a gallon of drench per 9-10 sq. ft. This simple technique fires up the microbes in the soil and the nutgrass simply fades away.
 
Poison Ivy Deciduous vine that grows in sun or shade and spreads easily underground. Has red berries and red fall color. Do not allow to flower and produce seed. Remove compost and spray new growth with vinegar based organic herbicides.
 
Purslane (Portulaca oleracea) Common purslane is an annual that grows rapidly in spring and summer. It thrives under dry conditions but also competes well in irrigated situations. Low growing. Leaves are very succulent and often tinged red. Small yellow flowers are born singly or in clusters of two or three. Flowers usually open only on sunny mornings. Purslane seeds are very tiny and produced in abundance. Entire plant is edible and nutritious. It really shouldn’t be treated as a weed.

Queen Anne's lace (Wild Carrot) This lacy weed-like plant got its common name from the legend of Queen Anne of England (1665-1714) pricking her finger and a drop of blood landing on white lace she was sewing. Part of the carrot family, Queen Anne’s lace is a biennial that is also known as wild carrot. Early Europeans cultivated it and Romans ate it as a vegetable. American colonists boiled the taproots, sometimes in wine as a treat. It is high in sugar, second only to beets among root vegetables. It was used by the Irish, Hindus and Jews to sweeten puddings and other foods.
 
The Queen Anne's lace flowers resembles white lace and have a flat-topped white umbel, sometimes with a solitary red-purple flower in the center. The flowers bloom from late spring until mid-fall. Each flower cluster is made up of numerous tiny white flowers. The flower cluster start out curled up and opens to allow pollination. The cluster then rolls itself shut again, like a reverse umbrella when it goes to seed at the end of the season. The root smells like carrots.
 
Feathery leaves resemble the domestic carrot. The bases of leafstalks are broad and flat. Queen Anne’s lace leaves also closely resemble the leaves of the poison hemlock, fool’s parsley and water hemlocks, all poisonous cousins of Queen Anne’s lace. See below. Wild carrot can grow tall, most average about 3 feet tall.
 
Using first year plants are recommended. Roots are used in soups, stews and in making tea. First year leaves can be chopped and tossed into a salad. Flower clusters can be ‘french-fried’ or fresh flowers can be tossed into a salad. The aromatic seed is used as a flavoring in stews and soups.
 
Ragweed (Ambrosia spp.) Annual broadleaf that indicates droughty soil. Releases a potent pollen that causes hay fever. Control by cultivation, mowing, building the soil and spraying with vinegar-based organic herbicides.
 
Rescuegrass (Bromus catharticus) Cool-season annual bromegrass. Control by broadcasting corn gluten meal in early October or before seed germinates.
 
Roadside Aster (Aster exilis) Small white flower in late spring. Usually is found growing in fairly poor soils. It will not compete with turfgrasses if the lawn is healthy. Easy to control by increasing the vigor of the lawn. Use the organic program, top dress problem with compost and water consistently. Dry molasses at 10 – 20 lbs. per 1000 square feet will also help.
 
Sandbur (Cenchrus pauciflorus) Annual grass plant that produces a bur with strong, sharp spines. Seeds in the bur can lie dormant in the soil for years before germinating. Control by increasing the carbon in the soil with humates, dry molasses and/or corn gluten meal.
 
Spurge (Euphorbia spp.) Sappy succulents, annuals or perennials that like hot, dry weather. Control by spot spraying vinegar-based organic herbicides.

Spiderwort Tropical spiderwort (Commelina benghalensis) or benghal dayflower is a weed. It is perennial, similar in look but not related to Tradescantia spp., the ornamental spiderwort. Highly invasive and problematic to gardeners and farmers in the southern states and considered a noxious weed nationwide. It spreads not only by self-seeding above ground, but produces small seed-producing flowers underground. It also spreads by root nodes on any broken pieces left in the soil. Control by spot spraying with vinegar or fatty acid products or by applying the commercial product Agralawn Crabgrass Killer. By the way, it is resistant to glyphosate (one of the dangerous ingredients in Roundup) that shouldn’t be being used anyway. Tropical spiderwort is easily confused with Virginia buttonweed.
 
Strawberry, Mock or False (Duchesnea indica) also known as Gurbir and Indian strawberry, it has strawberry-like foliage and an aggregate accessory fruit similar to true strawberry. This groundcover-like plant spreads easily by stems and seeds to become seriously invasive. It can be controlled with the Agralawn Crabgrass Killer. This is the weed at my place where I learned about the power of this organic product.

Virginia Buttonweed (Diodia virginiana) is one of the most difficult-to-control broadleaf weeds. It does well in poorly drained areas and can tolerate low mowing heights. It is a deep-rooted perennial that produces both above- and below-ground flowers. Its prolific seed production, extensive root system and ability to vegetatively reproduce make control difficult. It is a spreading perennial with opposite leaves that often have a mottled, yellow appearance due to a virus that commonly infects the foliage. Stems are occasionally hairy. The aboveground flowers are white and star-shaped with four petals. Fruit are often green and elliptical with hairy ridges. It produces deep taproots and rhizomes can be found as deep as several feet deep. It can form very dense mats in established turf. Above-ground fruit are buoyant, allowing them to be transported with surface water to other areas. Virginia buttonweed can also reproduce from stem fragments. Clippings from mowing or weed eating can establish into mature plants. Hand removal of Virginia buttonweed is often ineffective because any stem fragments or rhizomes left behind can produce new plants. The Agralawn Crabgrass Killer is a good tool for crabgrassclover and chickweed control. It also controls Virginia Buttonweed in turf. 

Wild Onions This is an edible wild flower that most people consider a weed.  I have had luck and others have reported success killing them with kindness. Mow, clip or pull as often as you can and apply a heavier than normal application of molasses. Use about 10 lbs. per 1000 sq. ft. and repeat in two weeks. The mixed products that contain molasses, cornmeal and wheat bran will also help. The idea here is to stimulate a furious level of biological activity aimed at rotting the crowns of the undesired plants. Crow poison looks almost the same and is mildly toxic.  Wild onion has a strong onion fragrance when crushed; crow poison does not. Control with soil improvement and organic herbicides.

Wild violet Annual or perennial depending on species. Has heart shaped glossy leaves. Produces flowers in a variety of colors ranging from white, purple, pink, and yellow. Reproduces from seed and underground runners. I consider it a pretty wildflower but can be killed with any of the organic herbicides if necessary.
 
Yellow Sorrel (Oxalis stricta) Also called yellow wood sorrel, it is a native North American plant (also found in Eurasia) and grows from underground stems (rhizomes). The leaves are most often green, but may also be purplish or brownish red. Its leaves fold up at night and open again in the morning. It also folds its leaves when under stress, such as when growing in direct sun or during storms. The plant may reach 6-15" in height. It prefers moist soil and partial shade, but is also commonly found growing in cracks in sidewalks. The yellow spring/summer flowers are about a half-inch in diameter. They may occur singly or in clusters of up to five flowers. Wood sorrels are also called sourgrasses or shamrocks. They are delicate, and yet can withstand being walked on, mowed to within a quarter inch and poisoned. It'll grow in sun or shade, good soil or poor. And, it is an edible plant. The whole plant produces an orange to yellow dye.
 
 
 

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