Jonno wrote:
Jonno wrote:
While there are many types of Ivy , most will give you trouble..
see here and ask around...

http://en.wikipedia.org/wiki/Toxicodendron

http://www.inmygarden.org/archives/2...ing_poiso.html
Apparently, from memory it was grown in Australia early in the 19
century and exported for some reason. i believe it was medical. But
interesting stuff with dangerous consequences. Most Doctors seem to
know about it...
Not as widespread as first thought by me but still something to know
about. Especially as its easily mistaken for other ivy..

"ORNAMENTAL USES

Poison-ivy has other economic significance. Hard to believe, but
poison-ivy has been cultivated in gardens in New South Wales, Australia,
and in Dunedin, New Zealand, and sold as an ornamental by English
nurserymen, probably as far back as 1640. Colorful autumnal foliage is
used to highlight displays of fruit at shows-and it does not escape
cultivation! (16).
DERMATITIS

The recorded history of poison-ivy dermatitis began in 1609. In his
account of his experiences with poison-ivy in Virginia and Bermuda,
Capt. John Smith wrote: "The poisoned weed is much in shape like our
English ivy, but being touched, causeth redness, itching, and lastly,
blisters, and which, howsoever after a while pass away of them-selves,
without further harm; yet because for the time they are somewhat
painfill, it hath got itself an ill name, although questionless of no
ill nature" (11). Indeed, Toxicodendron sensitivity is doubtlessly the
prototype of allergic contact dermatitis in the U.S., having afflicted
the very first white settlers (11). Lack of recognition of the plant in
all its forms is the chief cause of exposure (10). Only humans and
closely related primates get the dermatitis (5). Symptoms from the first
exposure to the allergen in the various species of Toxicodendron are
extremely rare. Probably seven out of every 10 people in the U.S. can
develop this allergy if exposed to the toxin a second time. With
subsequent exposures, however, symptoms may develop 12 to 72 hours later
or in less time in highly sensitive

individuals (12). Both poison-ivy and poison-oak may cause severe
dermatitis on contact; even breathing smoke from burning plants is
harmful (3). Transmission from smoke is by droplets on particles of dust
and ash via the smoke, rather than from gas. Smoke from burning
poison-ivy plants or contaminated articles can carry the poison in a
dispersed form (13).

With time, sensitivity to poisoning can change. Generally, persons
repeatedly exposed to poison-ivy and poison-oak become more sensitive
because they react to lower concentrations of the oily toxicant. And
people usually become less sensitive as they get older. But this rule
does not always hold true. Persons who have waded through patches of
poison-oak numerous times without effect can suddenly develop a severe
rash after such contact. Occasionally a person becomes less sensitive
after a serious bout of poisoning by such plants (12). The dermatitis
rarely lasts longer than 10 days (5). The plant sap contains urushiol, a
yellowish slightly volatile oil that causes the allergic reaction on the
skin. Contacting the oil sets off a skin eruption that can vary from a
simple itching inflammation to water blisters, which exude serum in the
most severe cases, making infection a real danger (5, 12).

Urushiol is carried in specialized vessels or resin ducts in the phloem
of the plants. It normally is not present on the surface of leaves or
twigs nor in the stamen or the pollen of the flowers. It is found within
the resin ducts in leaves and flowers, and the bark of stems and roots
in all Toxicodendron species. When the leaves are bruised, chewed by
insects, or otherwise damaged, then and only then will the poison exude
from the poison ducts onto the leaf surface. The fluid changes in a few
hours to a black gummy substance (12). Urushiol can be toxic for an
indefinite period; several 100-year-old herbarium specimens have been
toxic to sensitive persons who have handled them (12). Contrary to many
old wives' tales, eating a poison-ivy leaf does not confer immunity (7).

Objects such as clothing, gloves, and tools can convey the poison. Once
contaminated they are often the sources of prolonged infections. Dogs,
cats, and livestock frequently contact the plants and transmit the
poison to children or other unsuspecting persons. The poison can remain
on the hair of animals for a considerable time after they have gone
through patches of poison-ivy (12). Cattle, horses, sheep, hogs, and
other livestock apparently do not suffer skin irritation from these
plants, even though they graze on them occasionally. Poison-ivy is
heavily browsed by deer. Bees collect nectar from the flowers, but no
ill effects from contact with honey have been reported (12).

MEDICINAL PROPERTIES

Inconceivably, in North American medicine the acrid juice from fresh
leaves of poison-oak was formerly pre-scribed for its "irritant,
stimulant and narcotic" principles "in palsies, paralysis, drowsiness,
stupors, delirium, rheumatism, stiffness, herpetic troubles [and]
certain other eruptive diseases" as a "visicant for producing blisters."
At one time poison-oak was officially listed in the Pharmacopoeia of the
U.S. Although the plant was introduced into England in the 1640s, it was
not used in medicine there until the end of the 18th century when it was
utilized in the treatment of stubborn herpetic eruptions 13).

The sap from poison-oak leaves has irritant, narcotic, and stimulant
principles, and in small doses is a nervous system sedative. A tincture
of the sap is used for relieving nettle stings, ringworm, eczema, and
rheumatism (13).

SEED DISSEMINATION

At least 55 species of birds are responsible for the wide distribution
of poison-ivy seed (15). After eating the fruits of T. radicans, the
seeds are voided near trees, fences, and telephone lines (10). Because
of this, the pest is increasing throughout the country since the plant
is usually left un-molested in such areas (6)."