Brambleweed

Brambleweed is a snarl of gray-brown, thorn-studded vines with no leaves at all; the stems themselves carry out photosynthesis. Only the tips of the vines grow. Behind each advancing tip the older stem dries out and turns hard, so the plant builds its own scaffold as it spreads. That dried underbramble stays tough enough to shield the fresh green shoots, and once hardened it will not burn.

The plant never attacks, but anyone thrown or shoved into it is in serious trouble. Every 10-foot square holds about 100 thorns, 1 to 2 inches long, each doing just 1 point of damage. When a victim lands in it, make an attack roll for the brambleweed; on a hit, roll 1d100 to learn how many thorns strike home, at a single point apiece. Most who fall in die trying to work their way back out, bled white by deep cuts or impaled outright, and many creatures have perished trying to force a path through a thicket to reach something on the far side.

Growers raise a bramble tree by planting one of the thickest stems upright and lopping off its top again and again. Each cut forces the plant to add a fresh outer layer. Once the stem is as thick as wanted it is allowed to grow, with steady pruning to keep it shaped. A straight run cut from a section about four inches around makes a fine thorny staff or club that deals double the damage of a plain one, thanks to dozens of 1- to 4-inch thorns along its length. A wielder who fumbles has a good chance of spiking himself on his own weapon.

Communities plant brambleweed around homes and water sources as a defensive hedge and grow bramble trees for arms. How tall and far the growth spreads depends on available water and on tending; the best way to push it along is to sprinkle a little water on the green tips each morning and evening. A well-thorned bramble staff sells for four times the cost of an ordinary wooden one.