Dragon bone column, also known as keel, is triangular, multi-branched, blue-green, 4 meters to 5 meters high, with small thorns on the edge, which is extremely short. Dragon bone column has white flowers in summer, 4-9, clustered at the base of thorns, which are open at day and closed at night (potted plants are generally not easy to bloom), and the berries are small and round, blue-purple and edible. The whole plant is sweaty white milk, which is poisonous.

Dragon bone column belongs to Dracaena of Cactaceae. Its plants are triangular, multi-branched, blue-green, 4 to 5 meters high, with small thorns on the edge and extremely short thorns. Dragon bone column is called "all-round rootstock", which can be grafted with Rosa davurica and Crab claw orchid, and it is colorful.

Nine columns and twelve columns are spectacular. The specific plastic methods are as follows: When the nine columns grow to 20 cm to 30 cm, cut off the top with a sharp knife and immediately seal them with plant ash. After the plant grows branches, only the top three branches are left, one at each corner, and the rest are erased. When the second layer grows to 25 cm to 30 cm, the top is cut off again. After the branches are born, choose three branches, three at each corner, that is, 1, 3, 9-shaped keel. The angle selection method of twelve columns is the same as above, except that when the length of nine columns is 20 cm to 30 cm, the top is cut off, and then three branches are cultured, and each angle is selected as 1 or 3. Other twigs are erased with the increase of length, keeping the tree shape consistent.

Keel, in the application of home, not only has the function of eliminating evil, but also has a good purification function. For the newly renovated house between home and office building, it has a good adsorption effect on formaldehyde, benzene, radon, ammonia and TVOC.