Category Archives: Invasive

Weed Control

by Sharleen Pratt, Master Gardener in Training

Some of Mother Nature’s weedier creations can become a real nuisance in the garden because they rob other more desirable plants of nutrients, moisture and light. If they become established, they can be very difficult to control, therefore, it is highly recommended for the health of your plants, that you weed on a regular basis. The best time to weed is right after it rains as the weeds will be much easier to pull.

A weed is generally any plant that is not welcome in your garden! They are usually plants that can grow in any kind of soil, reproduce prolifically and interfere or compete with other more desirable plants. Many weeds have been introduced from another country and often become invasive. They can be very difficult to control and it is important that all gardeners try to prevent these particular plants from taking hold and spreading through their neighborhood.

Weed Identification can be intimidating! A few of the more common weeds, generally found in your lawn are:

BROADLEAF PLANTAIN, Plantago major (pictured above)

Broadleaf plantain is a perennial weed that spreads rapidly by seed and new shoots arising from the roots. Broadleaf plantain is distinguished by its rosette of dull green, oval leaves with thick green stalks, and its elongated spikes of tiny green flowers. Each flower is followed by a small egg-shaped pod with 5 to 15 tiny dark brown or nearly black seeds that are rather glossy. The flowers set seed from spring until late autumn. Broadleaf plantain is easily removed with a dandelion fork. It can be out-competed in a lawn by over-seeding and aeration.

COMMON CHICKWEED, Stellaria mediastellaria-media-846435_640

The common chickweed may be an annual, winter annual or perennial. They have small white flowers with 4 to 5 petals. They reproduce by seed and by horizontally spreading leafy stems that root at the nodes. Common chickweed will flower through the spring, summer and fall. One plant can produce 10,000 to 20,000 seeds. The seed remains viable for up to 10 years.  Hand-weeding is best when the seedlings are small. It can be reduced by over-seeding since chickweed doesn’t like a lot of competition.

PURSLANE, Portulaca oleraceaPurslane

Purslane is a summer annual, reproducing by seed. It has fleshy leaves and stem, which lie prostrate on the ground. The seeds in small capsules are black, kidney-shaped and extremely small. An average plant produces 60,000 seeds. Purslane is one of the most common weeds in gardens throughout Ontario. Though rarely producing roots from the stem, if even a small portion of the root of an uprooted plant touches the soil, it can grow a new root system and become established. It is easily pulled and dies at first frost.

CREEPING BUTTERCUP, Ranunculus repensbuttercup

Creeping buttercup is a perennial and reproduces by seed and runners. There are two common buttercups, one is a tall buttercup and the other is a creeping buttercup. The tall plant does not have runners and, therefore, reproduces by seed only. Both will flower in early spring to the end of July. Flowers are bright yellow, about 1 inch across. Each plant is capable of producing up to 250 seeds. The first leaves are kidney-shaped and somewhat hairy below. This weed is poisonous to grazing animals, and care should be taken to control it from spreading. Creeping buttercup survives best in moist location, so any improvement in drainage will help to control it. Persistent cultivation will also help, as well as constant mowing.

CREEPING CHARLIE or GROUND IVY, Glechoma hederaceaCreeping-Charlie

Creeping Charlie, also known as Creeping Jenny or Ground Ivy is a perennial which reproduces by creeping tangled rootstocks and also by seed. It is part of the mint family. The leaves are opposite and palmately veined. They have a bright green surface. The seeds are smooth and dark brown. The plant reproduces well through its surface runners. It has rapid growth in early spring and is a persistent plant whose leaves and stems stay green under the snow, allowing it to flower early. It flowers in spring around the same time as the dandelion. This plant spreads easily in a lawn, particularly in shady areas. Close mowing will help. If possible, be sure to dig out the small seedlings by hand in early spring. With large patches, heavy mulch or newspaper would help to kill an infestation.

FIELD BINDWEED, Convolvulus arvensisbindweed-2453936_640

Field bindweed is a perennial weed that spreads rapidly by seed and creeping roots. It is a hairless, twining, or trailing plant with deep, cord-like roots. There is an extensive spreading, underground root system. The creeping white rhizomes have been reported to grow up to 30m in length and 5m deep. Under favourable conditions, plants may flower within 6 weeks of germination and the twining nature of the plant can cause serious problems with crops. It is part of the morning-glory family. Seedlings can tolerate frost temperatures of minus 8C. Seeds can remain viable for up to 50 years. A severe infestation of bindweed is capable of producing over 800 kg of seed per acre.

An excellent website to help you identify weeds is: