|Submitted by: Diane Harris
Date Submitted: 6/25/2003
Location: Healdsburg California
Question Asked: These photos are of a bush in our back yard. We live in Healdsburg California which is in Sonoma County. This bush is about 10 ft. in diameter and 5 ft. tall. It drops its leaves in the fall after turning many colors of red, orange and yellow. There are little berries that can be seen in some of the photos. I think that there are blossoms in the spring but can't remember. This bush has been something pretty until now when I have a serious case of poison oak. My doctor thinks that I got it from our cats. We have no poison oak anywhere on our property but after paying very close attention to the 3 leaf formation of this plant I am wondering. My husband has taken a sample to our local nursery but two or three people have said it is not poison oak. Help!!!
Answer: Hi Diane -
That is quite a handsome shrub you have there. Unfortunately, I'm not as familiar with west coast shrubs and am unable to tell you what it is positively. I wanted to say that it wasn't poison oak as all that I've seen is very distinctive and consistent in leaflet shape (like little white oak leaves). After doing some research on poison oak in California with specific examples, I'm now less certain.
The pictures of the fruit aren't clear enough to positively help here. Normally, the fruit looks like little clumps of whitish fruit (almost like a little clump of grapes). Also, as a shrub poison oak is generally smaller in the 3 to 6 foot range. So with the leaflet shapes, the fruit and the size of your plant I'm inclined towards it not being poison oak. I did find a California park website (Morro Bay - about 300 miles from you) that had pictures of poison oak leaflet diversity, so here is where the confusion for me lies. I'm including a link to the top page of the poison oak information on that site: Western Poison Oak by Curt Beebe, docent, Morro Bay State Park Museum of Natural History. The section on "Leaf Diversity" is interesting with many pictures of leaflet variations.
So, Diane, I'm not much of a help to you with your pictures BUT I do have a test for you that can help put your mind at ease (or frighten it based on test results). It's a simple test and should only take about 30 minutes. You'll need a blank sheet of white paper (like office or copier paper) and a good pair of gloves (PVC coated is best). Don the gloves and break off a leaf where it meets the stem (not a leaflet but a leaf with the 3 leaflets on it). Put the end of the leaf (the wounded end where it was on the stem) against the paper to create a dot of "juices". Dispose of the leaf and remove the gloves with proper cleanup. Now wait - if this plant is poison oak the dot on the paper will turn black within about 30 minutes. Urushiol oil which is the toxin contained in poison ivy, oak, and sumac oxidizes fairly quickly turning yellow then darker until it is black.
I'd love to hear back from you on the results of this test. I'd like to be able to properly categorize this plant. Thanks!