Invasive Plants doesn't seem to want to die
These plants pop up everywhere around our yard in Sparks, MD. We have tried round up, brush killer, 2-4-D and none seem to have any effect. Vinegar and salt didn't seem to have any effect either. Any help anyone could provide would be extremely helpful. We are on well water so that is a concern. Some have told us it's Tree of Heaven but none get that big. Also interesting is the plants on the front of our property are darker green leaves than these but have the same appearance in leaf etc.
We do not think this is Tree of Heaven, which would have a tiny 'thumb' at the bottom of the leaf, and if you crush a leaf, would smell like rotten peanut butter.
Your second photo shows what looks like a long tendril reaching out, which makes us think this is a vine.
Invasive vining plants in our area are most commonly Japanese Honeysuckle and Wisteria. This looks more like Wisteria.
Either way, systemic herbicides containing the active ingredient triclopyr (found in products like Brush-B-Gone) or glyphosate (products similar to Round Up) like you used should work.
Review your label directions.
It can take several weeks for the plant to take up the herbicide and to die back.
If you followed label instructions, just wait.
As far as the color of the leaves, this could be a result of differing soils. The darker green plants likely have a richer soil with more Nitrogen available to them.
What has us perplexed is they never have flowers .The plants in the picture are about 1.5 ft tall. I took the pictures looking straight down. Root structure is substantial over 8 inches long. There are extremely large roots nearby we haven't been able to fully remove that we believe to be the source but can't verify. Large root is every bit of 15 ft long and has a white paper peeling exterior similar to what a birch tree trunk would look like.
These plants continue to pop up everywhere. Within a few days 3-4 new plants will shoot up 8-10 inches tall with a week's time. Root diameter of each plant itself is 1/8 inch
Wisteria is very, very aggressive and invasive. It can run underground and pop up far from its origin.
You wouldn't see flowers because plants can take years to be mature enough to bloom, but they can eat up a landscape before then.