The Municipality of Port Hope responds to concerns about noxious weeds. These plants are of public health concern because touching them or their sap can result in painful skin rashes and burns. Noxious weeds found on municipal property are reviewed based on risk and location assessments and manually or chemically controlled with registered and licensed products where required.
Under the Weed Control Act of Ontario, property owners are responsible for taking action to control noxious weeds on their property. If you decide to take measures to control these plants, regardless of the method used, wear protective clothing and goggles to cover exposed skin and protect your eyes.
The Invasive Species Centre provides photographs of each noxious weed for ease of identification.
Poison Ivy
Poison Ivy is widespread throughout southern Ontario and is toxic to the skin. The offending substance of the plant is an oil which is present throughout root, stem, leaf, flower, and fruit. Poison Ivy grows in deep woods or in the open; in dry, sandy areas, crevices of rocks, or swamps; along the borders of woods, fencerows, or roadsides. Each leaf consists of three leaflets. Leaves may be red, green, or slightly yellow.
Poison Ivy is classified as a noxious weed under the Ontario Weed Control Act. This legislation provides a means for regulating control of certain weeds in problem areas. Cooperation and united effort are essential to controlling Poison Ivy, but responsibility falls to each person to recognize it, teach others to recognize it, and avoid contact with it.
Common Reed (Phragmites)
Also known as roseau commun, invasive phragmites is an aggressive plant that spreads quickly. It can grow up to 5 metres tall and forms dense stands with tan-coloured stems, blue-green leaves, and large, fluffy seed heads. This invasive species outcompetes native plants for water and nutrients by releasing toxic biochemicals into the soil.
One factor making identifying this plant tricky, is that it is closely related to a native variety. Generally, native Phragmites do not grow as tall as the invasive plant and does not out-compete other native species. Unlike the native variety, its leaf sheaths cling tightly to the stem, and it spreads rapidly through an extensive underground rhizome system. Commonly found along roadsides, ditches, and wetlands.
To help manage invasive Common Reed, start by learning to identify the plant. Avoid disturbing or cutting it without a proper plan, as this can worsen its spread. On small properties, you can control it by cutting stems below water level in late summer and covering the area with tarps to block sunlight. After removal, replant with native vegetation to prevent regrowth and restore ecosystem health.
Giant Hogweed
Giant Hogweed is an invasive plant species that can grow to a height of 5 to 6-metres. It thrives in moist soils such as riverbanks and wetlands and disturbed areas such as uncultivated or waste areas, roadways, and agricultural fields. Giant Hogweed is dangerous when skin is exposed directly to the sap. The plants toxins can cause severe skin irritation when the skin is exposed to sunlight. The sap is found in the leaves, stalk, flower and roots of the plant, making it dangerous to handle. If you come into contact with giant hogweed, wash the affected areas immediately with soap and cool water, do not touch your eyes, eliminate exposure to sun and seek medical advice.
Japanese Knotweed
Japanese Knotweed is an invasive perennial plant species that poses a threat to our local environment. Japanese Knotweed grows rapidly, forming dense thickets and can grow 10 to 13 feet tall. Heart or shovel shaped leaves with a pointed tip are arranged alternatingly along the stem and small creamy white flowers bloom in late summer and early fall in clusters on the tips of stems. Stems are speckled with reddish-brown patches. Aggressive growth of Japanese Knotweed can outcompete native species plants reducing biodiversity, disrupt natural ecosystems and habitats, and weaken the stability of riverbanks and buildings. To protect out community and prevent the spread of Japanese Knotweed, we ask that residents and visitors do not disturb the plant and report any sightings on Municipal land using our Report an Issue tool.
Poison Sumac
Poison sumac is distinguished by its appearance as a coarse shrub or small tree, its alternately arranged, pinnately compound leaves with 7-13 usually smooth-margined leaflets and its clusters of white flowers followed by whitish berries. The entire plant is as poisonous to most people as Poison-ivy. Because both the foliage in summer and the bare twigs in winter can cause severe dermatitis, take special care to avoid these parts touching hands or face when in damp woods.
Dog-strangling Vine
The Dog-strangling Vine is a plant that forms thick strands that overcome and crowd out natural plants and trees. It prefers open, sunny areas but can be found in natural and disturbed areas. It is also found in shaded forests. In recent years, this lookalike member of the milkweed family has spread quickly throughout central and southern Ontario.
The plant produces thousands of seeds per square metre. The seeds can easily be spread by the wind. This perennial vine has invaded ravines, hillsides, fence lines, stream banks, and roadsides. Damaging results from dog-strangling vine are that it can destroy vegetation, agricultural fields, and block access into trails. If nothing is done to prevent the spread of the vine, it will suffocate trees by climbing up and wrapping itself around the leaves. The vine threatens the monarch butterfly. The butterflies lay their eggs on the plant, but the larvae are unable to complete their life cycle and do not survive.
Options to control the vine are chemicals, mechanical, cultural, biological, and combined weed management. A natural control for the vine is the Hypena Moth which is currently being tested in Ontario.