Toxic Plants in the Lower Mainland

I'm interested to learn about potential toxic plant hazards that exist in the lower mainland. Specifically, I would like to know which plants can cause a contact dermatitis reaction similar to the reaction characteristic of Poison Ivy.

I have been told that Poison Ivy itself doesn't grow in the lower mainland. This seems indeed to be the case since I have never seen it growing here, and I can identify it in an instant (I'm originally from Ontario).

However, I have also been told that Poison Ivy does grow in the interior of BC. Is this true?

Also, some websites I visited suggested that Poison Oak is a hazard in the lower mainland. I've never made a positive ID on this plant, so I can't say for sure, but I don't think I've ever seen anything like it.

I have seen Stinging Nettles growing her, but the reaction produced by them is not of a character comparable to the Poison Ivy reaction.

One other thing: apparently Devil's CLub can cause contact reactions? Just by contacting the leaves? What about those thorns? Any ideas?

Thanks,

psi4ce

[Daniel Mosquin]

It seems unlikely that either poison ivy (Toxicodendron rydbergii) or poison oak (Toxicodendron diversilobum) can be found in the Lower Mainland (it seems I'd have to check herbarium records to be sure). The Illustrated Flora of British Columbia suggests that poison oak can be found on the Gulf Islands, southeast Vancouver Island and possibly Howe Sound (last collection was prior to 1950). Poison ivy is more a plant of the south interior in British Columbia, although it seems to come as far west as Princeton.

Plants that can cause dermatological reactions that can be found in the Lower Mainland include (reference: Plants of the Pacific NW Coast by Pojar and MacKinnon):

Heracleum spp. (the cow-parsnips) - photodermatoxic (light-activated reactions!).

Hypericum spp. (St. John's worts) - also photodermatoxic. Compounds are secreted by glands in the leaves.

Oplopanax horridus (devil's club) - can cause boils where the spines break off under the skin.

Pojar and MacKinnon also suggest that leaves of many ranunculids (buttercup family) can cause irritation when applied to the skin, but I suspect that the contact has to be persistent (not a casual brush of the leaf surface like with poison ivy).

In any case, none of these plants use volatile oils like poison ivy and poison oak, so proper clothing serves as good protection. Also, unlike poison ivy, you don't have to be cautious when handling clothes that have come in contact with them.

I'd be interested to look at the websites that suggest poison oak is a hazard in the Lower Mainland - that seems to contradict the information I have.

[jimmyq]

Timber press has a good poisonous plants book.

Thank you for the interesting information.

What a relief that the dreaded Poison Ivy doesn't grow here in the Lower Mainland. In Ontario it is incredibly prevalent; a constant menace. I have seen groves of it so thick that the individual plants are are big as shrubs. Even in the dead of winter the woody stalks stick up out of the snow--and they're still dangerous to touch!

So Poison Oak isn't expected in the Lower Mainland. That's good--I'll rest a little easier. Those websites that say Poison Oak grows in SW BC... Maybe they should be a little more specific...

Photodermatoxic--I wonder, does that mean that you have to get the plant in contact with the skin and then have light shine on the contacted area in order to have a reaction?

Buttercups have never seemed to be a problem.

I'm a little concerned about contact with Devil's Club, but somehow I have my doubts that the leaves are as serious of a contact threat. I say this because I am aware of the fact that Poison Ivy & Oak secrete (as you mention) a "volatile oil" that is apparently highly characteristic of this type of plant. Devil's Club is quite obviously not the same type of plant.

Still--I'm confused since I apparently picked up something recently when out scrambling in the bush here on the North Shore, and if I didn't know any better I'd *swear* it was Poison Ivy...

[Daniel Mosquin]

Yes, that is what photodermatoxic means. The compounds that get on the skin become irritating after being exposed to light. Heracleum is out now, and it does grow on edges of trails (particularly where there is moist soil). The reaction can be quite severe. I personally haven't experienced it, though.

If you are getting that spreading itch associated with poison ivy (and I'm familiar with it as well, being from Manitoba), there is always the slight possibility that a population of plants (either poison oak or poison ivy) exists after being transported to the area (perhaps from a seed on a boot or from the chains of a mountain bike). When you say scrambling in the bush, do you mean hiking along one of the marked trails? I generally hike on the North Shore at least once a month during the summer and can make a note to check the trail you were on (if you were on one).

Another possibility is that it doesn't have to do with your scramble in the bush - there are a few fairly common cultivated plants that can provoke a similar reaction to poison ivy in people who've experienced poison ivy before, such as sumac (which is in the same family of plants). Sumac generally isn't a problem, but if you've had reactions to poison ivy in the past, I'd say it is a remote possibility if you've had recent contact with it.

Devil's club, since it causes boils, might cause similar skin reactions to poison ivy - but the irritation shouldn't spread.

Ah, here's a resource to beat all resources on this subject:

The Botanical Dermatology Database

While browsing through the Araliaceae section (for Oplopanax), I noticed that it mentions English ivy (Hedera helix) can cause poison ivy like irritations in sensitive individuals...

As is the way with these matters, there are a bewildering variety of possibilities.

I suppose it is possible I encountered a highly localized "alien" population of either P.I. or P.O... I'll keep a lookout. Because of my interest in ecology, I'm almost always scanning the underbrush to keep a running catalog of plant life that I'm passing by. I would be really terrified if I discovered P.I.!!!

Trails--I'm on and off marked trails all over the place. I live up here on the North Shore and I'm an active mountaineer in the North Shore mountains. I cycle to work on trails and I scramble in the underbrush on a regular basis. Therefore, I'm not even totally sure where I picked up my little dermatologic reaction. Actually... the one place I suspect most based on where I've been recently and when I started to notice the reaction... is Lighthouse Park. But I'm not certain.

Hmm... Sumac? Yes I've seen it growing in the Lower Mainland. I've even seen it growing in Lighthouse Park if I'm not mistaken. However I was under the impression that only a specific variety of Sumac is poisonous in the same manner as P.I... That variety apparently is an East Coast phenomenon.

I suppose however that sensitive individuals such as myself can never be totally certain...

[PG Greenthumb]

The oils in Junipers can cause like type symptoms in a lot people, along with Cedars (Cedar itch).

Another good book is Botanical Dematology,Plants injurious to the skin Mitchell &Rook. Greengrass press
Vancouver 1979

[rashena]

i have been infected with poison ivy. it happened while i was soaking at the hotsprings in the naksup area. the plant is growing in abundance all around the area.

[rashena]

i have seen poison oak in the kootneays as well as poison ivy.

[Ashgrove]

Some years ago I found poison ivy growing abundantly in the lower Stein Valley, near the beginning of the trail, in fact alongside the trail.