Q: We have a hill that is planted with English ivy. It is doing very well but we now have a plant that is invading and choking the ivy. We do not want to harm the ivy but if it means getting rid of this plant we will.
A: The plant is sheep sorrel, Rumex acetosella, a perennial invasive weed. My native plant friend Shannon Pable reports that the leaves are very tasty in a salad!
In a shady area, I doubt it could choke out the ivy because ivy is so shade tolerant and sorrel is not.
In full sun, sorrel might give ivy a run for its money. In that case, you’ll have to try a process of hurting the sorrel more than the ivy. I’d do an experiment using half-strength Weed B Gon on a patch of mixed ivy and sorrel. Observe the area for three weeks. My guess is that the sorrel will be hurt more than ivy because ivy has such waxy leaves.
If your observation confirms this, repeat the sprays every six weeks until the sorrel is under control.
Let me know how it turns out!