The Homeowners Column

The Homeowners Column

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Exposure to sun and plants can be a blistering experience

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator
slmason@illinois.edu

Seems every time my forays into the fields and furrows of my garden yield a few battle scars. The raspberry bush tries to give me a hug or a rose cane attempts to trip me. I usually just consider it my red badge of workage. However, one spring I emerged with more than just a few scratches. Soon after working in the garden, I developed blisters on my arm reminiscent of poison ivy. With no poison ivy in sight, I knew it had to be something else.

I surveyed the trail of weed carcasses stretched out along my garden path, right past the lovely small, blue-green leaves of an herb called rue. I once heard tales of skin reactions to rue, but the blistering experience had remained just a garden tale.

Now I understand why I hadn't previously succumbed to rue's rash side. Rue has glands throughout the plant that contain a volatile oil that reacts with the sun (specifically Ultraviolet - A) to produce itching, burning, red spots and/or large blisters in some people. Red blotches may remain for months after blisters heal. The reaction occurs within a few hours of exposure to the plant and sun. That's the catch - the reaction requires exposure to the sun. The oils in rue are predominantly located on the surface of the leaf so oil transfer is effortless. In addition, the oils can be transferred to clothing and pets. Unfortunately, numerous other plants can cause this kind of reaction known as photo dermatitis.

Generally, the plant's leaves or stems have to be broken to release the oils. This time of year as people mow, weed and spend time in the sun it sets the perfect stage for photo dermatitis reactions. Beyond rue pay particular attention also to garden and weed plants in the spurge family and dill family. Members of the spurge family often have milky sap and include ornamental euphorbias and weedy spotted spurge.

In the dill family some people may see a slight reaction from skin exposure with dill, parsley and Queen Anne's lace. A greater reaction is more common in the weedy plants of the dill family such as wild parsnips, water hemlock, poison hemlock, cow parsnips and the dreaded giant hog weed. If you want to be grossed out, do an internet search of "giant hogweed skin reaction". Be very careful when mowing or weed whacking ditch banks, pastures and field edges where these weedy plants may hang out.

https://extension.illinois.edu/photolib/lib2211/poison%5Fhemlock%5Fleaves.jpg

With ornamental plants such as rue and euphorbias you may decide to eliminate these plants from your garden, or you could work around the culprits at the end of your work day to reduce sun exposure. Wearing long sleeves and gloves in the garden is always a good idea, especially with photo dermatitis plants. In addition, after gardening, mowing or weed whacking, immediately shower or wash skin with soap and water. Also wash all clothing in hot soapy water and not with the family wash. If you have questions about plants and skin reactions, contact your physician.

Learn to identify plants that cause photo dermatitis reactions and take proper precautions to eliminate exposure.

Check out UI Extension fact sheet on Plants that Cause Skin Irritation Give us a call 217.333.7672 or stop by our office for a copy 801 North Country Fair Drive Suite D Champaign, Il 61821.

Saturday, July 9, 2016 "Our Story Garden" Garden Walk beginning at First Presbyterian, 302 West Church in Champaign at 10 AM. Seven houses of worship throughout Champaign/Urbana tell a shared story of the Grand Prairie with four pollinator friendly "anchor plants" then each garden is filled with annuals and herbs to tell the story of the host congregation. "Our Story Gardens" is a pilot partnership between Faith in Place and the Park Districts of Champaign and Urbana. Tour is free.

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