Ivy, for example, can quickly smother a wall, it is difficult to kill and unless done with care, its removal can damage the mortar joints and soft stone or bricks.
Gall iorwg, er enghraifft, orchuddio wal gyfan yn gyflym, mae'n anodd ei ladd ac os na chewch wared arno yn ofalus, gallwch ddifrodi'r uniadau morter a cherrig neu frics meddal.