The Arson Plant
I rather like these two paragraphs from “Doomsday” in which an alien plant something like a giant squash is described
” The arson plant and the forest had been at war for centuries, and had reached an impasse on this hillside. Kat had compared the plants to Terran beavers, but militant, napalm-armed kudzu might have been more apt, and the foothills were filled with evidence of their destructive, ongoing struggles of conquest. Their thick, vigorous foliage crowded out competitors while incendiary seed disbursal simultaneously helped claim new territory and exposed neighboring trees to intense, repeated fire until first the light, and finally the land, was surrendered.
But here, the steep and rocky terrain had tipped the balance ever so slightly in favor of the conifers, and the invaders were stymied. They could not grow densely enough to kill the trees and take the hillside, but they could never relent. A botanical Sisyphus, they constantly rebuilt their arsenal, awaiting the spark that would begin the next futile cycle of assault and stalemate, while the conifers, anchored by sturdy roots, held the sky and controlled the light. Dylan and his compatriots had simply drawn their own attackers into one skirmish between the two Methuselan armies.”