Would a splash Doom Shroom deal 30/40 damage to everyone on a full board? Also if nothing else, wheelbarrow is a puffball with 0 damage and 2 scrap health
cattail pvz1, homing thistle pvz2. okay sure game, I'm sure your zombies with "movement abilities" and "lane switching" make Lesser plants shiver in their boots. (missle toe is cool tho, with their on-demand chump blockers & retaliation damage to cripple swarms.)
Given that they didn't make Doom Shroom an item, like Potato Mine was, probably intentionally don't want a 12 DMG nuke every fight or just wasn't designed with Injury Bell enabled (Just durian + barrage + moko charm, ez)
In the first game, Flower Pots were similar to Lilipads in which they were selectable at the beginning of a round and plantable throughout a world - they only get used for Roof levels because they're a requirement for those levels, but they can technically be used in other levels. They can't be placed on water however, even on Lilipads (my guess is that they take up the same slot on a tile as a lilipad)