This spell could be cast at one plant or object made from wood, shrubs, or vines up to 150 ft (46 m) away. If the target was an intact plant, such as a dead tree, the spell affected the entire plant. Otherwise, it could alter about 14 cubic feet (0.4 cubic meters) of wood or objects made of wood, such as a desk, a pile of wooden shields, or a part of a bridge. The transformation lasted at least 50 minutes. Higher level casters could extend the range and duration of the spell, and increase the volume of plant material affected.
Greenwood caused the target plant or wooden object to sprout leaves and appear green and healthy. This foliage was typically enough to conceal one medium-sized creature, but not enough to be used for entangle. Dry or seasoned wood became fresh, unseasoned wood, and could bend, sag, or snap if put under stress (like a ship's mast or a bridge support). If cast on unlit kindling, the material became impossible to ignite. If cast on a burning campfire, the flames died down to a mere flicker and the fire gave off thick smoke that caused choking and extremely poor visibility in the immediate area. The smoke produced could fill a volume one hundred times the size of the fire source and reduce vision to two feet (sixty centimeters). Those caught in the smoke had one chance to resist the magic of this spell or else they found their combat effectiveness reduced and they became easier targets for enemies.
After the spell expired, the affected plant material returned to its original state, but retained any damage or warping that occurred while the wood was green. If the wood was previously rotten, worm-eaten, or unsafe to bear much of a load, greenwood temporarily turned it leafy and lively, but usually hastened its disintegration or collapse when the spell ended.
This spell required verbal, somatic, and material components to cast.