I was at a lecture this week where the speaker suggested doing just that. He was talking about when you paint stumps with round-up, but I don't see why you couldn't add it to a spray container. I'd just make sure I was wearing something I didn't care about in case a gust of wind blows the dye back at you.

I can't determine if number 3 is poison ivy, but it is definitely not poison oak or sumac. Would need an up close picture of the leaves. Number 2 is too small for me to tell, as well. I am suspicious of number 1 being poison ivy or oak, though.* None of the plants are poison sumac. That is a definite. Here is how you can tell if you have poison ivy: 1. There will be 3 leaflets on one leaf stem, continuing up the branch in sets of 3. This means that the branch will never have single leaves growing from it. (Poison sumac is different) These leaflets will NEVER occur directly across from each other, they will always be alternate. 2. The middle leaflet almost always has a longer stem than the other 2. It never has a shorter stem. 3. The leaflet's side veins (not the main vein that goes from stem to leaf tip) are alternating in pattern, never across from each other. * This is the reason I am suspicious of number 1 possibly being poison oak or ivy. 4. The base of the leaf stem will be thickened, like a celery stalk. 5. Poison ivy flowers are tiny, white or pale cream, hang in clusters. They may or may not be fragrant. They will alternate on flower stem. 6. If flowers were present, fruit may show. It will be smaller than a pea, light green when young, white when ripe, resembling a tiny peeled orange. There will be black stripes between segments on the fruit. 7. If poison ivy is injured by bugs or damaged in any way, it will exude a resin. When this resin dries, it will make pitch black spots or lines on the plant. This is an excellent way to determine if you have poison ivy or oak. Using a shovel, crush part of the stem. By the next day, you should be able to see the black resin, if it is poison ivy or oak. 8. Poison ivy does not twine around trees. It's growth is pretty much straight up. 9. Eastern Poison Ivy vines, when established (think older plant), resemble old, frayed ropes, due to their aerial roots. Western Poison Oak will not have obvious aerial roots. Stems will be strong and flexible, not wimpy. New bark is reddish brown, older bark will be a weathered gray. New leaf growth is usually red, but not always. Fall color may be vibrant or dull. You will NEVER see the following: 1. Flowers growing from the end of a stem 2. Single, large flowers 3. Flowers any color other than cream or white 4. Upright flowers 5. Fruit larger than a pea 6. Red, blue, or purple fruit 7. Leaf stalks directly across from each other on the stem 8. Sharp spines 9. A vine twining like a barber pole Here is a link that might be useful: Poison Ivy This post was edited by AuroraWA on Thu, Jul 24, 14 at 0:44

Both are quite variable in leaf shape. Hortus III defines them with the same botanical name, Rhus radicans and or R. toxicodendron. Anyway, for sure #2 is poison ivy.

Running hot tap water over the affected area as hot as you can take it can relieve the itch long enough to get back to sleep. Sometimes very cold water helps also. I recently tried liquid benadryl (you rub it on the area) and it gave good temporary relief. I think cortaid has a relatively new product out but I have not tried it yet. After my two worst exposures I went to the doctor and got a cortisone shot which was very effective both times.