Wild Parsnip is in full bloom now and while beautiful, it can leave marks on skin as its sap reacts to ultra-violet rays of the sun.
If you suddenly notice unusual brown discoloration of your skin with little or no accompanying discomfort, or weeping blisters from an unknown source, you may have come in contact with the sap from a plant containing a chemical compound called “furanocoumarin”.
Common plants containing this chemical include celery, wild parsnip, fennel, dill, parsley, wild rhubarb, lovage, mustard and chrysanthemums. Some of the furanocoumarin compounds are photoactive, which means that their toxicity is enhanced by ultraviolet radiation, and their impact is magnified by humidity and perspiration, so gardeners, beware!
While beautiful, wild parsnip plants can leave permanent scars on exposed skin. The sap can cause skin to react to sunlight, resulting in intense burns, rashes or blisters. Brushing against these plants can result in a brown discoloration on the skin with little or no accompanying discomfort, or weeping blisters. The toxicity of the chemical compound is enhanced by ultraviolet radiation, and its impact is magnified by humidity and perspiration.
Symptoms begin with significant pigmentation changes which usually take 24 hours to appear, making it difficult to link the cause to the effect. The exposed skin turns brown, and the resulting marks resemble scars from a burn, and in fact they are burns as the skin is reacting to a component of the plant which causes a hyper-sensitivity to long-wave ultraviolet light. The irregular marks resulting from exposure have been known to resemble handprints, and have been occasionally been mistaken for evidence of child abuse. Another common pattern is a splatter formation resulting from the use of a weed wacker. For those who are very sensitive, the burning of the skin can persist for 48 hours, by which time the exposed area may swell and develop itchy, weeping blisters resembling the reaction to poison ivy. Reactions to this compound typically last for several months, but affected area may remain scarred and hypersensitive to ultraviolet light for many years. The severity of the reaction depends on the individual’s sensitivity to the compound.
Wild parsnip is an invasive species that also appears on the provincial list of toxic weeds. It spreads readily, with seeds spread by wind, water and on mowing equipment. In its first year, the plant establishes low clusters of flowers as the roots develop, but by the second year it flowers on a stalk that can stretch to 1.5 metres tall. It forms dense stands which spread quickly if left undisturbed. At the moment, many of our rural roads and cropped fields are edged with wild parsnip plants, but it can also become established in abandoned lots and neglected areas intown. It is labeled toxic because it reduces the quality of agricultural crops including hay, oats and alfalfa, and its chemical compounds can reduce weight gain and fertility in livestock that consume it.
There are a few options for homeowners looking to remove small clusters of these plants on their property. Wear protective clothing and rubber gloves, removing them carefully to avoid transferring any sap onto your skin. Wash any exposed skin and limit sun exposure for 48 hours after coming in contact with the plant.
Because of the plant’s long taproot, permanent removal can be achieved by smothering new plants with plastic for an entire season to ensure plants are completely dead. Herbicide products that include glyphosate can be effective but require multiple treatments and are subject to provincial and federal regulations. DO NOT BURN or compost plants. Dispose of them by placing them in black plastic bags and leaving them in direct sun for at least a week. Plant material can then be disposed of in your regular garbage bag.
For more information, visitwww.omafra.gov.on.ca.