Ask at garden centers. It's acceptable for organic growers. The vinegar dissipates quickly and won't alter soil pH, so you can plant directly into the sprayed areas though it'd probably be a good idea to put down a layer of black plastic or cardboard and grow squash or melons there this season; give it a whole growing season to prevent last year's seeds from germinating.
It seems to be a thistle, but I am inclined to believe it is a biennial type like musk, bull, Scotch or tall thistle, rather than Canada thistle. Thistles can be difficult to identify without a stalk and flowers.
The leaves in the photo seem to be hairy, with fairly uniformly-lobed margins. In contrast, Canada thistle leaves are smooth on the topside key characteristic , with irregularly-lobed margins.
Canada thistle is a creeping perennial, typically found in patches. As a perennial, it is difficult to eradicate because pieces of roots often survive. Biennial thistles have a first year rosette stage similar to the photo , and produce a flowering stalk in year two. For biennial thistles if there aren't too many plants , you can eradicate them by chipping out the crown of the rosette with a spade before they bolt and flower. The only way to successfully remove this WEED from your yard that I have found is to manually dig it up, root and all.
I dont believe in spraying chemicals. Roseann Sorrentino commented, I agree, I dont spray chemicals. I have seen natural and organic soil type of weed killers and repellents in large bags. Just as expensive as really bad Miracle Gro. You need to log in if you'd like to add an answer or comment. Musk thistle is one of the more common biennial noxious thistles and is relatively easy to identify because it often grows in excess of 6 feet tall, has very large flowers that tend to droop, and the flower has very characteristic brown bracts that resemble pine cones Figure 2A.
The flowers usually are deep rose, solitary and very large, ranging from 1. The average musk thistle plant produces in excess of 10, seeds per plant, and under favorable conditions may produce , seeds per plant.
Seed germination generally averages 30 percent. Rosettes are dark green with a light green midrib and often grow 2 feet or more in diameter Figure 2B. Rosette leaves usually are smooth and lacking pubescence. Musk thistle generally invades areas that are especially dry and overgrazed. Musk thistle seed is dispersed readily after introduction, so plants infest many acres in only one or two seasons.
Infestations generally are more dense than with other biennial thistles, but less dense than perennial noxious thistles. Flowering is indeterminate, starting in early June and continuing for at least eight to 10 weeks. A late-blooming cycle often occurs just prior to frost. Seed from the late bloom primarily is responsible for the limited success of seed-feeding weevils Rhinocyllus conicus introduced for biological control of musk thistle.
These insects attack the earlier blooms but have completed their life cycle before the last flowers set seed. Figure 2A. Musk thistle flower with large brown bracts and the tendency to nod or lean because of the large size of the flower.
Figure 2B. Musk thistle rosette, which often grows 2 feet or more in diameter, with no pubescence on the underside of the leaf, which helps distinguish it from plumeless thistle rosettes.
Bull thistle generally is the least serious of the noxious thistles. It occurs in all 48 contiguous states and most of Canada, but is designated noxious in only four states. The plant grows 2 to 6 feet tall.
A distinguishing characteristic of bull thistle is the leaves Figure 3A. Leaf margins are deeply toothed, and toothed again double dentate with prominent stiff spines. The leaves have prickly hairs above and are cottony below. The plant appears bushy rather than the candelabra appearance of plumeless or Canada thistle Figure 3B. Figure 3A. Double dentate leaf with long, stiff spines at each tooth, prickly pubescence along the leaf midvein and winged stem, which is very pubescent during the rosette and early bolt growth stages of bull thistle.
Figure 3B. Bushy appearance of bull thistle with spiny, conical shaped flower heads. The seeds germinate readily; however, seedling survival is low and bull thistle generally is found as single or scattered plants. The rosettes of bull thistle are very pubescent with dark purple ribs. The heads are gumdrop-shaped with long, stiff yellow-tipped spines. Bull thistle flowers from July to September, which is somewhat later then other thistles in the region.
The flowers usually are purple, but a rare white flowering variety has been collected in the region. P erennial thistles, such as Canada [Cirsium arvense L. Arthur] and wavyleaf thistle [C. Top-growth control is not enough; one must design a program to deplete the root system for effective control of a perennial thistle. Both wavyleaf and Flodman thistle are native species that generally are only a problem when the land has been overused.
Canada thistle was introduced from Europe, and like many introduced weeds, has spread rapidly because of the lack of natural enemies. All perennial noxious thistles are aggressive invaders and can become the dominant species in an area within a few seasons of introduction if not properly controlled.
Canada thistle was introduced in North America as a seed contaminant in both French and British colonies. The first legislation to control the weed was passed by Vermont in Canada thistle grows best in the northern U.
Canada thistle is adapted to a wide range of soils, but it produces deeper roots in clay or muck soils than in sand, gravel or limestone soils. Canada thistle requires a to hour photoperiod to bolt and flower, and growth ceases when temperatures exceed 85 degrees for extended periods.
Canada thistle is considered to be naturalized in the northern Great Plains. Canada thistle usually grows 2 to 3 feet tall and bears alternate, dark green leaves that vary in size Figure 4A. The leaves are oblong, usually deeply cut, and have spiny, toothed edges. Canada thistle has been classified into several varieties.
Within these varieties are many ecotypes that differ in growth characteristics, response to day length, and susceptibility to herbicides and cultivation.
For example, leaf shape, head structure, and the number and size of spines can differ with ecotype. Stem color also can differ from green to lavender.
Flowering occurs from June to September. Male and female flowers are produced on different plants, so cross-pollination is necessary for seed production. Flowers produce from 40 to 80 seeds per head. The smooth, light brown seeds have a conical point and are loosely attached to a tannish pappus at the tip, which aids in seed dispersed by wind. Seeds mature rapidly and are able to germinate within eight to 10 days after pollination. Canada thistle overwinters in the rosette growth stage Figure 4B.
Canada thistle generally spreads from field to field in contaminated crop seed or forage. Within a Canada thistle population, some seed remains in the flower head or falls at the base of the plant. Cultural control Digging up the plants can be done at any time of year but cultural control methods are not easy but can work if consistently applied; Digging up creeping thistles is problematic because the roots will easily regenerate from broken pieces.
Persistence will be needed Weaken creeping thistle by repeatedly cutting down the top growth over a number of years. This is best done just before the flower heads show colour as much of the weed's food reserves will have been used up in flower production Clearing by digging may take two or three seasons as the plants will easily regenerate from small fragments that have been overlooked Weedkiller control The best time to apply weedkillers to thistles is when they are growing vigorously, but have not yet flowered.
Several applications may be necessary to gain control In rough grass areas, apply Vitax SBK Brushwood Killer, a selective herbicide based on triclopyr In borders and unplanted areas Apply a systemic weedkiller containing glyphosate e. Roundup Fast Action, SBM Job done General Purpose Weedkiller or Doff Advanced Weedkiller; or for spot treatment use Roundup Gel just before the flower heads show colour Spray the foliage thoroughly, which should turn yellow after about a week Watch for any signs of regrowth the following year.
You may find that two or three treatments are needed Glyphosate is not selective and any nearby plants or grass coming into contact with the spray may be killed Ensure you follow the directions on the packaging of weedkillers Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS.
Download Weedkillers for gardeners Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 1a, 1b and 4 Links Chemicals: using a sprayer Chemicals: using safely and effectively Chemicals: using spot and broad-scale weedkillers Weeds: non-chemical control. See also RHS video: weed control. You may also like. Brambles and other woody weeds. Japanese knotweed. Nettles as weeds. Weeds Ragwort Ragwort Senecio jacobaea is native Weeds Bindweed Hedge bindweed or bellbind Calystegia Weeds Brambles and other woody weeds Woody weeds such as brambles.
Apply herbicides to kill thistle, especially in spring and fall, before thistles can flower and seed. Use glyphosate for your garden, and use a broad-leaf herbicide containing 2,4-D or MCPP for your lawn. Since glyphosate kills all plants, you must keep application specific.
Use a sponge to apply, or cut thistle plants and then use an eye-dropper to put a drop or two into the stem. If done early enough, you can use chemicals in Hosta beds as Hosta typically sprout late so a chemical treatment will not affect it. Pre Emergent treatment of Preen granules can be used. MVG also offer a product called Burn Out which is environmentally safe. Put down mulch liberally. It conserves moisture, enriches the soil and prevents germination of new thistle.
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