Please assist this is sprouting in my back yard in lawn and also in hedges and under trees, I am not sure if poison oak or Ivy, can you please help to identify as my wife is highly allergic.
It is growing like both bush and vine
the plant in the center of your image appears to be a young peppervine, Ampelopsis arborea, and each leaf has more than 3 leaflets, which rules out poison ivy. In the second image you sent there is a smaller plant with 3 leaflets per leaf that looks a lot like poison ivy, but on closer inspection, it also seems to be a seedling of the Ampelopsis. It is a common native vine. I do think that some people can get a rash from the peppervine, but it is actually related to the grape rather than to poison ivy, You should be able to eliminate it easily with treatment by Roundup or another herbicide, but remember that Roundup will likely kill any plant it touches so avoid using it on or near plants you do not want to lose.
I should also mention that seedlings of the popular Koelreuteria tree also have similar seedlings, so I am not 100 percent certain.
Steve Hill, Ph.D., Botanist, SCNPS