VARIOUS TYPES OF SOIL CONDITIONS 179 



made to be sure that the artificial bog garden can have moist soil condi- 

 tions which will be congenial to the plants in this location. 



Peat soils are not only naturally acid but it is believed they con- 

 tain low forms of plant life also which are of great assistance in pro- 

 moting the growth of ericaceous plants that especially thrive on peaty 

 soils. Peat bog soils lack available nitrogen and therefore carnivorous 

 plants occur, such as pitcher plants and sundew. 'Humic acid is pres- 

 ent and low temperatures are the prevailing ones. The humic acid 

 acts upon the roots of the plants. Plants adapted to peat are likely 

 to be those requiring considerable humus also a cool, moist, deep, loamy 

 soil and a position not in full sun when transplanted. 



Since in a light, sandy soil the particles are relatively large such a 

 soil is generally well aerated and not retentive of moisture. Thus, 

 plants adapted to such a soil are as a rule very hardy and possessed of a 

 large root system due to the fact that the roots generally have to ex- 

 tend considerable distances in search of water which may fail just 

 when most needed, that is, during summer droughts and winter freeze- 

 ups accompanied by a drying wind. Also since this soil type is well 

 aerated it is not likely to contain much humus or to be acid in char- 

 acter as the aeration or oxidation of the humus removes one cause of the 

 soil acidity. 



On the other hand, clay soils are composed of very fine particles, 

 poorly aerated, and are retentive of moisture and tend to be acid in 

 reaction. Therefore, plants adapted to clay soils are generally mois- 

 ture loving, free from large fibrous root systems, and are not nearly so 

 likely to be hardy, especially if removed to another soil type. 



Light soils are said to be warmer than heavy ones. What is really 

 meant by that is that the period of growth from spring to autumn is 

 longer on a light soil than on a heavy one. For this reason, plants 

 which start growth early in the spring, like peaches, or bloom late in 

 the autumn, like chrysanthemums, generally succeed better on a light 

 soil. For the present, and until the underlying reasons are better 

 understood, experience will prove the best guide in selecting plants 

 for the different soil types. 



LIST OF PLANTS ADAPTED TO VARIOUS TYPES OF SOIL 



CONDITIONS 



A. Boggy and Peaty Soils. Plants in this group have proved their 

 ability to thrive under extremely wet conditions in boggy, or peaty 



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