Category Archives: Invasive

Dog Strangling Vine

by Judy Bernard, Master Gardener

While taking a walk along one day along one of the lane ways along Crowe Lake, I spotted Dog Strangling Vine. It was because of the flowers that I recognized it.  They are very small, 5 to 9 mm long, star shaped and pink to dark purple in colour. The vines grow 1 to 2 metres long and will twine around structures, other plants or each other. The leaves are oval with a pointed tip, 5 to 9 cm long and grow on opposite sides of the stem. The flowers develop into a bean shaped pod filled with feathery seeds that are dispersed in late summer (similar to the milkweed pod, but much narrower).

DSV

The problem with dog strangling vine is that it can form dense stands that can overcome and force out other plants. Its leaves and roots are toxic to animals. It threatens the Monarch  Butterfly which will lay its eggs on the plant, but the larva cannot develop. (It’s related to milkweed, a plant necessary for the Monarch Butterfly.)

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I contacted the municipality and they have no program for its control, so it’s up to the individual property owner to be aware of it and to control its spread.

The Ontario Invading Species Program has information of how to control its spread.

If you already have some on your property, check out Best Management Practices. This also is from the Ontario Government.

 

Beware the Vigorous Plant!

By Suzanne Seryck, Master Gardener

Being the fairly recent owner of a small city garden, I find I no longer have the space for plants that either do not behave, need too much deadheading or pruning, spread too quickly becoming invasive, need to be staked or I’ve simply grown tired of. At least 90% of my garden is full of either fruit trees, shrubs, fruit bushes, perennials or raised vegetable beds. The remaining 10 or so percent contains a patio and a very, very small lawn that my husband tells me has to stay! So needless to say if I buy any new plants I have to give an existing plant or two away (thank heavens for plant sales).

I have a few plants in mind that I am considering replacing this spring so I have spent the last week or so looking through bulb and plant catalogues to see what is new this year. Catalogues are a great place to see what is new and exciting and also to fill the gardening void that generally happens this time of the year. However, I have heard both good and bad stories regarding plants purchased from these catalogues, so it is very much a personal choice. What I did notice though were the many different terms given to what I would describe as an invasive or ‘buyer beware’ plant, especially if, like me, you do not have a large garden.

allium

Allium were described as ‘carefree’. However, if you have ever tried removing hundreds of allium bulbs from a perennial bed that have self-seeded over many years ‘carefree’ is not a term I would immediately think of.

‘Vigorous’ is a term often used in these catalogues, which could mean either that the plant is strong, robust and grows well (which we would all like) or more likely that the plant grows very quickly and will take over your entire garden in a very short time. Examples of ‘vigorous’ plants include false sunflower (Heliopsis helianthoides), knotweeds (Persicaria) and orange trumpet vine (Campsis radicans).

Baby’s breath (Gypsophila) is listed with the description that it ‘readily fills gaps’, whereas bee balm (Monarda) is described as ‘multiplying quickly’.

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Lily of the valley (Convallaria majalis), need I say more! I actually inherited this plant in my shade garden and I think I could be digging it out for a good few years. I really do love this plant, but it has to be in the right location and in a bed all by itself. Lily of the valley is described in one catalogue as ‘creating a carpet of flowers’ and in another catalogue as ‘growing fearlessly among tree roots’.

But I think the term most often used to describe a plant that might become invasive in these catalogues is ‘naturalizing’. When I think of naturalizing I think of beds or daffodils or bluebells, but then I am English so that might explain why. Plants included in this category are masterworts (Astrantia), mountain fleece (Persicaria amplexicaulis), false sunflower (Heliopsis helianthoides) and meadow rue (Thalictrum flavum).

Being an avid gardener, some may even say obsessive, there are not many plants that I do not like and all of the plants listed above I have at one time or another grown, and still do. But gardening with only a limited amount of space has changed the way I look at and select plants.

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: www.omafra.gov.on.ca/english/crops/facts/ontweeds/weedgal.htm