Post by yihunt on May 25, 2008 10:36:08 GMT -4
Wildlife: Beware the nasty plants
Sunday, May 25, 2008
By Scott Shalaway
Urushiol, the oil found in Poison Ivy, causes the itchy skin rash.Improving backyard habitat for wildlife usually involves planting species that attract particular wildlife.
Trumpetcreeper, trumpet honeysuckle, bee balm and cardinal flower, for example, attract hummingbirds. Milkweed, Joe-pye weed and purple coneflower attract butterflies. And fruit-bearing shrubs and trees such as blackberry, raspberry, mulberry, holly and serviceberry attract robins, bluebirds, catbirds, cedar waxwings, mockingbirds and many other fruit eaters.
But as you garden for wildlife, be aware of some common plants that many consider nasty intruders.
Poison ivy (Toxicodendron radicans) tops the list of my unwanted plants. I have a long and unpleasant history with poison ivy. During my elementary school days I often had to stay home in late spring and early summer because the rash it caused actually swelled my eyes shut. My worst memories of little league baseball are playing games while my arms and legs were covered with an intense itchy rash.
My most embarrassing poison ivy moment came years later in graduate school in Michigan. I was doing a plant survey and came upon an unusual low shrub. The leaflets were bigger than my hand. I collected a few samples and as the day progressed, I got hot and sweaty. I repeatedly wiped sweat from my brow with my hands.
When I took the mystery plant to the herbarium, the botany grad students were equally mystified. The curator of the herbarium, however, just laughed.
"This will be a harsh lesson," he said. "It's poison ivy."
Sure enough about 36 hours later I had the worst rash I had in years.
So let me share the lesson. Poison ivy is a chameleon. It can grow as a vine, a shrub, or even a small tree. Its leaflets come in threes (hence the adage, "Leaflets three, let it be.") and they come in all manner of shapes and sizes. Finally, the surface of the leaves is always shiny, evidence of the oil (urushiol) that causes the rash. This irritating oil is present in all plant parts all year long, and it can remain active on dead plant parts for up to five years.
I had been familiar only with the vine growth form and had never seen leaflets so large, but I haven't been fooled since.
The best treatment for poison ivy is prevention. Anytime you suspect you may have encountered it, wash the exposed skin with soap and water within two hours of exposure so the urushiol won't have time to bond to the skin. Once it has bonded, however, you can only treat the symptoms until the rash runs its course in about 10 days. Severe cases can require a physician's care.
Fortunately for many people, including me, sensitivity to poison ivy often subsides with age. I rarely get a rash anymore, though I'm often exposed to it.
Still, whenever I find poison ivy in the yard, I spot control it with an herbicide formulated to control woody plants.
Stinging nettle (genus Urtica) is another plant that often invades the yard. It grows inconspicuously among the grasses that I weed by hand. That's why I wear gloves to weed. Tiny stinging hairs cover nettle stems and leaves. When they puncture the skin, they break and release a toxin that causes a rash and a stinging sensation that persists for hours.
Thistle (Cirsium) is also covered with spines on the leaves and flower heads. Thistle lacks nettle's chemical defense, but grabbing a handful of spiny thistle leaves is like shaking hands with a pin cushion.
Some other common backyard weeds are simply annoying. Sticktights or beggarlice (Bidens) bear small seeds armed with barbed prongs that instantly attach to anything they touch. I find them to be the most annoying of hitchhikers. They seem to cling almost adhesively to denim; I often use a knife to "peel" them off my pants. But it's an ingenious method of seed dispersal; animals that pick up sticktights carry the seeds far and wide.
Despite the problems posed by nasty plants, they do have virtues. A variety of birds eat poison ivy berries, many butterflies sip nectar from thistle flowers, painted lady caterpillars eat thistle leaves, and red admiral caterpillars actually prefer nettle leaves.
Scott Shalaway is a biologist and author and can be reached at scottshalaway.googlepages.com and RD 5, Cameron, WV 26033.
First published on May 25, 2008 at 12:00 am
Sunday, May 25, 2008
By Scott Shalaway
Urushiol, the oil found in Poison Ivy, causes the itchy skin rash.Improving backyard habitat for wildlife usually involves planting species that attract particular wildlife.
Trumpetcreeper, trumpet honeysuckle, bee balm and cardinal flower, for example, attract hummingbirds. Milkweed, Joe-pye weed and purple coneflower attract butterflies. And fruit-bearing shrubs and trees such as blackberry, raspberry, mulberry, holly and serviceberry attract robins, bluebirds, catbirds, cedar waxwings, mockingbirds and many other fruit eaters.
But as you garden for wildlife, be aware of some common plants that many consider nasty intruders.
Poison ivy (Toxicodendron radicans) tops the list of my unwanted plants. I have a long and unpleasant history with poison ivy. During my elementary school days I often had to stay home in late spring and early summer because the rash it caused actually swelled my eyes shut. My worst memories of little league baseball are playing games while my arms and legs were covered with an intense itchy rash.
My most embarrassing poison ivy moment came years later in graduate school in Michigan. I was doing a plant survey and came upon an unusual low shrub. The leaflets were bigger than my hand. I collected a few samples and as the day progressed, I got hot and sweaty. I repeatedly wiped sweat from my brow with my hands.
When I took the mystery plant to the herbarium, the botany grad students were equally mystified. The curator of the herbarium, however, just laughed.
"This will be a harsh lesson," he said. "It's poison ivy."
Sure enough about 36 hours later I had the worst rash I had in years.
So let me share the lesson. Poison ivy is a chameleon. It can grow as a vine, a shrub, or even a small tree. Its leaflets come in threes (hence the adage, "Leaflets three, let it be.") and they come in all manner of shapes and sizes. Finally, the surface of the leaves is always shiny, evidence of the oil (urushiol) that causes the rash. This irritating oil is present in all plant parts all year long, and it can remain active on dead plant parts for up to five years.
I had been familiar only with the vine growth form and had never seen leaflets so large, but I haven't been fooled since.
The best treatment for poison ivy is prevention. Anytime you suspect you may have encountered it, wash the exposed skin with soap and water within two hours of exposure so the urushiol won't have time to bond to the skin. Once it has bonded, however, you can only treat the symptoms until the rash runs its course in about 10 days. Severe cases can require a physician's care.
Fortunately for many people, including me, sensitivity to poison ivy often subsides with age. I rarely get a rash anymore, though I'm often exposed to it.
Still, whenever I find poison ivy in the yard, I spot control it with an herbicide formulated to control woody plants.
Stinging nettle (genus Urtica) is another plant that often invades the yard. It grows inconspicuously among the grasses that I weed by hand. That's why I wear gloves to weed. Tiny stinging hairs cover nettle stems and leaves. When they puncture the skin, they break and release a toxin that causes a rash and a stinging sensation that persists for hours.
Thistle (Cirsium) is also covered with spines on the leaves and flower heads. Thistle lacks nettle's chemical defense, but grabbing a handful of spiny thistle leaves is like shaking hands with a pin cushion.
Some other common backyard weeds are simply annoying. Sticktights or beggarlice (Bidens) bear small seeds armed with barbed prongs that instantly attach to anything they touch. I find them to be the most annoying of hitchhikers. They seem to cling almost adhesively to denim; I often use a knife to "peel" them off my pants. But it's an ingenious method of seed dispersal; animals that pick up sticktights carry the seeds far and wide.
Despite the problems posed by nasty plants, they do have virtues. A variety of birds eat poison ivy berries, many butterflies sip nectar from thistle flowers, painted lady caterpillars eat thistle leaves, and red admiral caterpillars actually prefer nettle leaves.
Scott Shalaway is a biologist and author and can be reached at scottshalaway.googlepages.com and RD 5, Cameron, WV 26033.
First published on May 25, 2008 at 12:00 am