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| "Poison ivy tree" |
Some time ago, the Treefanatic posted a little information
on poison ivy here. It is now full summer, and poison ivy has grown glossy and
lush in those places where no one has thought to eradicate it. Often, poison
ivy creeps in when one is not looking, and sets up housekeeping without so much
as a by-your-leave.
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| Detail of poison ivy tree |
In the photo at right, it has vanquished either an abandoned
utility pole or a dead tree trunk – it would take a braver person than I to
find out for sure. The location is a no man’s land between the Middletown Area
Transit bus-loading area, City Hall, and Melilli Plaza.
To the left of the “poison ivy tree” is some shrubbery that
is being strangled by bittersweet vines. When this picture was taken, a tendril
of poison ivy and one of bittersweet were meeting in the gap and preparing to
fight to the death. If the duel is allowed to continue, it will be interesting
to see which is the victor.
Vines occupy a unique evolutionary niche, since they are
adapted to accomplish the one thing other woody plants cannot: they travel, and
at an amazing rate. By travel, I don’t mean they merely grow all over the
place, although that is certainly the case. What is remarkable about their
growth habit is that they put out roots wherever they go.
A distinctive characteristic of mature poison ivy is the
mass of root hairs covering the woody stem – and these root hairs help to
anchor the vine even on something as solid as tree bark. In addition to sinking
down roots from above-ground stems, poison ivy can send up new plants from its below-ground, rhizome-like roots. When no trees or poles offer support, poison ivy adapts by becoming
shrub-like, or romping across the garden like a ground-cover.
Most vines provide gazillions of seeds through their
prolific berry production. Even poison ivy is a delicacy to some animals,
primarily birds, but sometimes raccoons as well. This allows the plants to pop
up anywhere and everywhere – usually directly under a bird’s favorite perch. This
is a fine example of the plant’s adaptation: birds eat the berries, excrete the
indigestible seeds around the base of a tree, the seeds germinate into a new
vine which climbs yet another tree. Poison ivy spreads by conquering new
territories – and, since birds often perch in trees at the edge of the woods,
the poison ivy is assured of growing in sufficient sunlight.
Poison ivy will grow in almost any type of soil, but it does
need a fair amount of sunlight. Usually you won’t find it growing in a very
densely shaded area – fortunately. In my garden, it often grows next to a native
wildflower called jewelweed, which some people find makes a great salve for
poison ivy’s rash. I have not tried it, but some studies have shown its value.
Jewelweed is related to the annual impatiens and has a sticky sap released when
its stem is broken.
Still, the best precaution is to avoid all contact with
poison ivy unless you are well protected with long sleeves, gloves and long
pants. And, since animal fur can pick up poison ivy’s oil, it’s wise to keep
pets far from it as well.
