Ivy Siege

The ivy siege spell must be cast upon a stone or brick building constructed upon the earth; flying castles and the like remain unaffected. Immediately after casting, ivy begins to grow at a fantastic rate, climbing from the ground up the building's walls. At the end of one turn, the ivy has climbed the walls. At the end of the second turn, green creepers have covered the structure. On the third turn, the ivy has deepened to a black-green and begins to squeeze the building.

Starting on the third turn and every turn thereafter, the building must make a saving throw against siege damage, as if attacked by a small catapult (see the DMG); Two cubic feet of the building crumbles away for each point by which the saving throw misses each turn. This cycle continues until the spell ends or the building is destroyed. The ivy rots away instantly when the spell ends.

A druid can cast only one ivy siege per building at a time. After the ivy has rotted away, the druid can cast the spell on the same building again. However, multiple druids can cast several ivy siege spells on the same building. In the case of a large, interconnected series of buildings (like a castle), each casting affects only a single tower, keep, or wall segment, to a maximum of 1,000 cubic feet per level of the caster.

The DM can choose to prohibit arctic and desert druids from using this spell if they are not familiar with ivy.

The material component is an ivy leaf.