Size: To 30 inches tall and wide.
Appearance: Canada thistle has spiny, gray-green leaves and purple flowers.
Appearance: This common lawn weed has a long taproot; leaves are deeply notched. Yellow flowers mature into puffballs. Dandelion seeds are like parachutes that fly away in the wind, helping them invade new spaces in lawns and garden beds.
Appearance: Identify garden weeds like smartweed by its lance-shape leaves often marked with purple chevrons. It’s an upright plant with pink or white flowers in summer and fall.
Type: Broadleaf annual.
Where It Grows: Sunny lawn, landscape, or garden areas.
Size: To 6 feet tall and 3 feet wide.
Size: Climbs 6 feet or more.
Type: Broadleaf annual.
Where It Grows: Shady lawn, landscape, or garden areas.
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Size: To 2 feet tall and wide.
Type: Broadleaf perennial.
Where It Grows: Landscape and garden areas in sun.
Where It Grows: Sunny landscape or garden areas.
Where It Grows: Lawns and gardens in sun or shade.
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Where it grows: Sunny landscape or garden areas.
Type: Broadleaf perennial.
Test Garden Tip: Thistle has an extensive root system that can grow several feet out from the main plant.
Appearance: Identify this garden weed by its light green leaves, clusters of white flowers, and dark purple berries.
Appearance: Identify this weed groundcover by its fleshy, dark green leaves and small yellow flowers at the ends of the stems.
Appearance: Pigweeds are tall plants with a taproot. Identify weeds by their hairy-looking clusters of green flowers (though some varieties are grown as annuals).
Native Americans called broadleaf plantain “white man’s foot,” because it seemed to appear everywhere white settlers went. Touted as a healthy backyard weed with various benefits, broadleaf plantain can create a small colony that resembles a ground cover if grass is thin and soil is dry and compacted. Hand pulling this weed is an effective solution, especially with small infestations. Plants have a fibrous root system and come up easily with a Three-Claw Garden Weeder. Or spray plants with an herbicide any time they are actively growing.
A non-native, invasive plant, garlic mustard grows in sun or shade, dry soil or wet. Its roots produce a chemical that inhibits other plants from growing. Thanks to these adaptations, it quickly colonizes areas. In many regions it’s displacing native forest plants, and in backyard gardens, it can quickly take over planting beds. Garlic mustard is a biennial, producing a small rosette of toothed, kidney shape leaves in Year 1, followed by a tall stem topped with flowers in Year 2. Remove (pull up stems and roots) and destroy any garlic mustard that appears on your property, putting it out with the trash.
These perennial weeds smell like their namesakes, and there’s no mistaking their presence when you mow over them. Wild onion has flat leaves, while garlic is round. They both grow from bulbs and form clusters similar to chives. To remove them, avoiding hand-pulling. It only serves to separate the main bulb from the tiny bulblets surrounding it, which remain in soil and sprout. To dig wild onion or garlic, excavate about 6 inches deep to get the whole bulb. Otherwise, spray with herbicide. The kind that kills nutsedge works on wild onion and garlic. In late spring, these weeds produce small bulbs atop long stems. Snip these and destroy them. They contain new bulbs—they’re this weed’s way of spreading and covering new ground.
Got weeds? Learn how to identify common weeds, including tips on why they’re thriving and how to get them under control.
This annual weed thrives in shady areas with moist, fertile soil, but it’s adaptable and can also sprout in dry areas. Chickweed forms a low-growing crown of stems that spread and sprawl. In a planting bed, the stems crawl through perennials and annuals, showing up as far as 12 to 18 inches from the plant’s crown. In lawns, it usually shows up in thin grass with heavy, moist soil. For a small infestations, hand-pulling works fine. Try to get plants up before they set seed, which can number up to 800 per plant. For heavy infestations, look for herbicides that list chickweed. There is also a perennial chickweed that spreads by seed and stem or root pieces.
Also known as wild morning glory, bindweed is bad news. Hedge bindweed spreads by seed and creeping underground stems; field bindweed spreads by weeds and roots, which grow up to 30 feet deep. These plants open flowers that look like morning glory, which is why many gardeners let them grow. They’ll grow along the ground like a ground cover, but if there’s a support nearby, like a rose, fence or tree, the vines twine and climb. Since these plants are tough to eradicate, it’s important not to let any get a foothold in your yard. Pull them as soon as you see them, and continue pulling each time they emerge. It will take possibly years for the roots to exhaust, but you can eventually beat them this way. For quicker kill, apply an herbicide that kills the root. It may still take more than one treatment, but you will kill these persistent plants.
This weed grows in poor, wet, compacted soil (think heavy clay). When nutsedge arrives in your garden or lawn, left to its own devices, it can quickly take over, establishing a colony. It looks like a grassy weed, but it’s actually a sedge. The individual blades have a strong center rib and are triangular in shape—a shape you can feel and see. The worst thing about nutsedge is that it not only produces seed heads, but also forms small bulbs or nuts underground. You can pull a nutsedge plant and still leave a network of nuts in the soil, each one capable of generating a new plant. The best approach is to spray plants with an herbicide. For nutsedge that’s growing in lawn, be sure to choose a chemical that won’t kill grass. A popular chemical is Sedgehammer, and it usually kills nutsedge with one to two sprays.
Keep an eye peeled in lawns and planting beds for sapling trees. Often these trees, like this walnut sapling, sprout thanks to the diligent digging of squirrels. It’s especially easy to miss these beneath mature shrubs or roses, until you spot the leaves poking through the plant. The other place that seedling trees pop up are along fencelines, courtesy of birds who have been gobbling fruit, such as mulberry, cherry or holly. Small trees are easy to hand-pull. Grab a spade if they seem firmly anchored in soil. Keep an eye out for seedlings in spring when weeding or mulching. Remove any you see before they have a chance to develop a tap root.
The nightmare of dandelions is the deep taproot (up to 15 feet long) and puffball seedhead, which disperses seeds on every breeze. The best defense against dandelions in the lawn is growing thick, healthy turf, which means mowing at the right height and fertilizing correctly. In planting beds and paths, these familiar weeds tend to show up in the worst places, such as rooted in the center of a perennial clump or tucked right in the edge row of paving stones. The best ways to get rid of dandelions? Spray them or dig them. When spraying, kick dandelions a bit first to scuff and wound the leaves—it helps the spray penetrate better. With digging, make sure you get at least 2 inches of taproot or they’ll return as two plants.
Canada thistle brings a thorny problem to any landscape where it appears. This prickly beast grows from seed that can blow into your yard, or it can sprout from root pieces, which sneak in with bulk topsoil or mulch loads. Size varies, with many mature plants reaching 5 to 8 feet tall. In a single season, one plant can produce a 20-foot-long root system, and it only takes one piece of root to produce a plant. Control through weeding, but dig carefully and deeply to get the horizontal root. After digging, if another sprout appears, pull it, too. Or use an herbicide. The best time to spray is as soon as leaves break ground. Spray repeatedly through the growing season, and you will eventually kill it.
Braod-leaved dock appears harmless enough when the red-veined leaves pop through soil in early spring. What’s important to know is that this non-native weed has the capacity to produce 60,000 seeds per plant, with each seed able to remain alive (ready to germinate) in soil 80 years. This is one weed you do not want to set seed. Plants start out small, but grow up to 4 feet tall. Dock is a tap-rooted weed, and that weed reaches up to 4 feet deep into soil. Digging it out is mostly impossible. The best control is using herbicide or vinegar on the young leaves as soon as they appear. Scuff leaves a bit before spraying to ensure spray penetrates the leaf coating. Repeat spray as needed. The taproot can generate more leaves over time, but keep spraying. The root will eventually use all its stored energy and stop growing.
When it comes to violets, opinions are divided. To some, it’s a weed of the vilest kind; to others, it’s a dainty wildflower. No matter which camp you support, it’s vital to know that while violets have a literary reputation of being shy, in the landscape, they are anything but that. This perennial bloomer boasts a prolific personality, spreading easily by underground stems and seeds. In the lawn, it adapts quickly to lowered mower heights, growing shorter as needed to dodge the blade. Violets thrive in moist, shady sites, but mature plants are drought tolerant. The solution to eliminating violets? Vigilant hand-weeding (be sure to remove all the rhizome) and targeted herbicide use.
Also known as oxalis, this is a versatile weed that grows in sun or shade, moist or dry soil. It’s a clover look-alike, with heart shape leaves and yellow flowers. Blooms fade to form upright seed pods that explode when ripe, flinging seeds away from the mother plant. It also roots from stem pieces. It’s happy to grow in lawns, planting beds, gravel drives or vegetable garden paths. Oxalis is a common weed in nursery pots, so be sure to check before adding plants to your landscape. The best way to beat it in the lawn is to mow high and fertilize to grow a healthy, thick lawn. In planting beds, carefully hand-pull or spray with herbicide.
Wild Onion and Garlic.
Privet is a shrub with a very tenacious root system that is very hard to pull out. It has small spoon-shaped glossy leaves and forms masses of black berries that are often eaten by birds that in turn spread the seed which can come up anywhere where birds deposit these ‘greeting cards’. Seedlings should be pulled out as soon as they appear but for larger plants, which can sucker from the root system, the best method is to chop the top off and immediately paint the freshly exposed stump with concentrated glyphosate solution. The treatment may need to be repeated more than once before the weed is completely dead and is most effective when the plant is actively growing during spring and summer. Other woody weeds that can be treated in this way include blackberry, gorse, lantana, sweet briar (Rosa rubiginosa), tree of heaven, willow, wisteria.
The list of weeds below covers the whole range of weed types and gives you strategies that can be applied to other weeds in your garden.
Annual weeds are those that complete their life cycle within a single year and usually propagate themselves by seed. Included are plants such as bindii and chickweed. Preventing these plants from seeding by either pulling them out or poisoning them when small and before they have flowered is the best way to get rid of them. If you let them drop seeds, you’ll have more weeds to deal with next year.
The simplest definition of a weed is that it’s a plant that you don’t want there. That means a plant can be a weed in one place and highly valuable in another. The key to keeping weeds under control lies in understanding how they propagate themselves and then taking steps to stop them doing that.
Wandering Jew- The fast growing, rapidly rooting stems are the problem with this shade-loving weed. The waxy leaves seem to make them resistant to most herbicides. You can easily pull it out by hand, however you must be particularly careful not to leave behind any little pieces of stem and roots, as they will take off again and choke out other plants again. If you have a particularly rampant infestation the best solution is to use a garden rake to collect up the bulk of the material. You can then meticulously remove the stems that are remaining or cover it up with several layers of newspaper followed by a very thick layer of coarse mulch such as woodchip or pine bark. Other weeds, which have similar habits, include the lawn grasses, kikuyu, couch and buffalo, and while these respond to the same treatment they are more susceptible to herbicides such as glyphosate.
2. Annual weeds that spread from seed.
Chickweed – This is a very fast growing annual weed that has small mid-green leaves and tiny white flowers that produce copious amounts of seed within weeks of the weed appearing. They can be easily removed by hand but this will usually result in many seedlings coming up within a few days. If you either dig them out with a garden fork or pour boiling water on them while they are small these seedlings can be effectively controlled. Bindii – This wretched plant produces spiny seeds that infest lawns. It is an annual that germinates in autumn and forms a prostrate mat that forms the mature seeds in late spring and early summer. By this time it is too late to prevent the seeds being a hazard (as they are still spiny even if they are dead) unless you dig each plant out individually, something that is only practical in very small lawns. The easiest solution is to use a selective herbicide such as ‘Bindii & Clover Killer’, however it is critical that you apply it when the plant is young to prevent the plant going to seed. Once the seed head starts setting, even if you kill the plant, the seeds can mature and fall to start the whole prickly cycle again. Other major weeds that fall into this category and can be treated the same way- Capeweed (Arctotheca calendula), catsear (Hypochoeris radicata), common sowthistle (Sonchus oleraceus), dandelion (Taraxacum officinale), fat hen (Chenopodium album), lamb’s tongue (Plantago lanceolata), pigweed (Portulaca oleracea) and shepherd’s purse (Capsella bursapastoris)
Onion weed – This plant belongs to the lily family and the reason why it is such a problem is that it grows from a bulb that rapidly multiplies into many small bulbs. The leaves have a grass-like appearance and it produces slender heads of small, white flowers. Trying to pull it out by the leaves usually leaves the bulbs intact underground and they simply sprout again. Trying to dig out the bulbs can work if you are very patient but it can often worsen the problem as it disturbs and spreads masses of tiny bulblets that form around the original bulb. Probably the best option is to apply concentrated glyphosate (the active ingredient of Zero, Roundup and several other popular herbicides) from a weeding wand, or spraying a larger area if there is no danger of hitting your desirable plants. It is very important to follow up the initial treatment as poisoning will kill bulbs that have leaves present but this in turn causes the small bulblets attached to them to sprout. If you don’t want to use herbicide, then you can exclude light until the plant dies by covering with plastic or similar. This will still leave the bulblets which will grow once you uncover the area, so you will need great patience with either herbicide or light exclusion to rid your area of onion weed. Oxalis – which can be recognised by its clover-like leaves and small lily-like flowers, poses the same kind of problem as onion weed as it also spreads from bulbs and bulblets. The bulbs tend to be closer to the soil surface which makes it an easier proposition to dig out successfully if you have the time, otherwise resort to the glyphosate treatment. Other plants that fall into this category include Montbretia , which has sword-shaped leaves and orange flowers that are attractive but this plant can be very invasive. Hand-pulling this weed is an easier proposition, as it is shallow-rooted. Other bulbous weeds that can be given the same treatment include; Watsonia , nutgrass (Cyperus rotundus) and onion grass (Romulea rosea)
Perennial weeds are those that live for more than one season and they may be either woody (eg privet and lantana) or herbaceous (eg kikuyu and wandering jew). Perennial weeds may spread by seed but often also by some vegetative means such as runners, bulbs or root suckers. This often makes them doubly hard to control as we have to not only stop them seeding, but also either kill or remove the vegetative structures as well which we need to look at case by case below.
These are a few examples of the worst weeds you will encounter. There are many others such as Madeira vine, Crofton weed that can be found in reference books. It should also be said that perennial weeds that spread from vegetative parts should be disposed of thoughtfully. They should not be thrown into the bush or on reserves, where they can regrow to become a nightmare to get rid of. Most councils now provide green waste collection services that usually result in weeds being thoroughly composted to the point where they are no longer a threat, or altenatively bag and bin them into the general rubbish collection.