Many allelopathic plants, like Juglans nigra and even grasses, use biochemical warfare to inhibit other plant's growth or kill them.

Mistletoe and other parasitic plants can rob nutrients from their host and, in some cases, result in the decline or death of their host.

Kudzu, some ivies, some wisterias, and other vines can cover all types of plants, strangling them and blocking light from their leaves.

Many other rusts (like white pine blister rust, cedar-quince rust, cedar-hawthorn rust, etc) are similar to cedar-apple rust in that they require two different species to complete their life cycle.

Besides rusts, there are other heteroecious diseases which require two or more hosts.

But thanks for the reply. I pretty much only plant natives to my general area and have seen what damage some invasive non-natives have done. We have ridiculous amounts of Chinese Tallow growing all over, some areas theres acres and acres of tallow monoculture 'forest'. Chinese privet fills in the gaps that the tallow leaves, and some type of tall thistle blankets over the pastures heavily in spring and early summer, but sporadically the rest of the year as well. Kudzu is not much of a problem in this area for some reason, but plenty of other vines (unidentified by me) are.

That one was for you, ken!

Interested in jugalone producing plants besides Black Walnut, and host plants for various rusts..

tj