WINTER CARE OF HERBACEOUS PLANTS 161 



There are several ways of making the plant ripen up its 

 wood. The principal method is to check its growth in the 

 late summer by the lack of water. The supply of water is 

 reduced by either stopping the cultivation of the soil, or by 

 planting some quick growing crop. The late growing plants 

 will rob the soil of its moisture and thereby take it away from 

 the plant you intend to winter over. In orchards the trees 

 are ripened by planting a cover crop, such as rye or clover, 

 late in the summer. This cover crop is allowed to grow the 

 remainder of the season. These quick growing crops rapidly 

 exhaust the soil of its moisture and permit the green wood 

 of the trees to ripen up before going into w r inter. 



Winter Killing of a Plant. — Some of the horticultural plants 

 are often killed by exposure to the cold weather. Such a 

 condition is called winter killing. In some cases only a part 

 of a plant is winter-killed, while in others the entire plant is 

 killed. Winter killing of plants is not due to any disease or 

 any insect, but it is due only to exposure. Authorities 

 differ as to what is the direct cause of winter killing. It is 

 thought, however, by many horticulturists that the death 

 of the plant is caused by the loss of water from the branches 

 of unprotected plants together with severe weather. Trans- 

 piration, as well as evaporation of the water in a woody 

 plant, takes place in the winter as well as in the summer. If 

 this loss of water becomes excessive, due to an abnormal 

 winter, many plants are killed. Strong winds or prolonged 

 warm weather during the dormant season is sure to cause 

 much winter killing, unless the plant is protected in some 

 way. Winter killing is also caused when the plants are not 

 properly hardened before going into the winter. 



Perhaps there is no better way of preventing winter killing 

 than to protect a plant from extreme exposure. The plant 

 can be protected from exposure either by building wind 

 breaks, or by covering the individual plants with material 

 of various kinds such as rye straw, burlap and manure. 



The Winter Care of Herbaceous Plants. — Plants whose tops 

 die down on the approach of cold weather while their roots 

 remain alive in the soil over winter are called hardy herbace- 

 ous plants. Such plants as the peony, rhubarb and asparagus 

 U 



