the present invention is a method of preserving plants which achieves reduced bleeding of the preservative material when the plants are subjected to elevated humidity conditions . the method comprises perfusing the plants with an aqueous preservative composition in which the preservative is primarily an alkylene oxide oligomer , 1 , 3 - butanediol , or 1 , 4 - butanediol . preferred alkylene oxide oligomers are di - and polyethylene glycols in the molecular weight range of about 200 - 1500 and di - and polypropylene glycols with an average molecular weight below about 450 . the preferred materials may be used with lesser amounts of secondary humectant materials selected from glycerol , ethylene glycol , propylene glycol , magnesium chloride or magnesium bromide hexahydrate , and water soluble cycle phosphonate esters . plants are conventionally treated by perfusing an aqeous treatment solution into the vascular system through a cut stem or other incision which exposes the xylem . treatment is carried out at a temperature in the range of 20 °- 50 ° c . at a relative humidity in the range of about 20 %- 80 % for a period time up to about 14 days .