Or make it so that the plant is the larval stage of the wyrm. It grows, fruits into wyrms who leave and rampage and mate, and then when they're ready and fertilised the wyrms return to any part of the plant network in the biome. The new DNA is incorporated into the plant network, and the wyrm dies, having done its work. Its body is turned into fertiliser, and the cycle begins anew.

Maybe there's a breeding season where a lot of wyrms are born and only the best return to the motherplant?

Swamp wyrmplants are the apex predator of swamps

Eats ranidurans and sloshantes