PURPOSE: To obtain a film material for a plant, having suppressing actions on the evaporation of water and water retaining actions in grafting, cutting and planting a tree, excellent in appearance without requiring the removal after root taking and having biodegradability with salt injury preventing effects.

CONSTITUTION: This coating material for a plant is obtained by adding a water- soluble polymer such as gelatin, carrageenan. carboxymethyl cellulose, methyl cellulose or polyvinyl alcohol to a natural rubber latex capable of forming a film layer 8b by spraying thereof onto the plant 60 and air-drying the resultant mixture and has the biodegradability.