Poison-ivy can be grubbed out by hand quite readily early in spring and
late in fall. When the ground is soft after rains the roots come out in
long pieces. Grubbing when the soil is dry and hard is almost futile,
since the roots break off in the ground, leaving large pieces that later
sprout vigorously. Eradication by grubbing is permanent if well done.
Because of his close contact with the plants, the person doing the
grubbing should have a high degree of immunity to ivy-poisoning. Many
people are not so immune as they believe, and it is common sense to wear
leather gloves with gauntlets and a shirt with long sleeves. If care
is taken to prevent the poison-ivy from touching the face, and if the
clothes, including the gloves, are burned or thoroughly washed after use,
severe poisoning may be avoided.
Poison-ivy vines climbing on trees should be severed at the base and as
much of the vine as possible pulled away from the tree. Often the roots
of the tree and weed are so intertwined that grubbing is impossible
without injury to the tree. Close mowing of the poison-ivy shoots at
frequent intervals is the only remedy. Roots and stems removed in
grubbing should be burned or otherwise destroyed, since the dry material
is almost as poisonous as the fresh. Care must be taken to keep out of
the smoke.
Old plants of poison-ivy produce an abundance of seeds, and these are
freely disseminated, especially by birds. A poison-ivy seedling 2 months
old usually has a root that one mowing will not kill. Seedling plants at
the end of the first year have well-established underground runners that
only grubbing or chemicals will kill. Seedlings are a constant threat as
long as old poison-ivy is in the neighborhood.
Plowing is of little value in combating poison-ivy unless followed by
persistent stirring with a cultivator or harrow, to keep all roots
loosened from the soil. Otherwise plowing merely propagates the weed.
Mowing with a scythe or sickle is a common method of attacking
poison-ivy, but it has little effect on the roots unless frequently
repeated. The number of cuttings required to kill depends upon the age of
the plants and the size of the roots, but is seldom less than four. New
shoots should be cut as soon as the first leaf on each stem is full size.
Cutting either earlier or later delays eradication.
Weed burners are implements resembling oversize blowtorches. Two types
are manufactured, one producing a short, hot, blue flame and the other a
long smoky-yellow flame. Both are useful for destroying foliage. Neither
is likely to kill perennial plants like poison-ivy at one operation, even
though the flame is held on the weeds for a minute or more until leaves
and stems are completely incinerated. The roots are not injured by this,
and new leafy shoots soon develop. A better plan is to "sear" the plants
by passing the flame slowly over the vines just long enough to sear or
wilt the leaves, but not long enough to burn them. The roots appear to
be injured more by "searing" than completely burning the leaves, and the
operation is quicker and cheaper. Three to four searings when the leaves
reach full size usually kill the roots.