TREES AND SHRUBS FOR THE NORTHERN PLAINS 39 



Salix jragilis. — This species has been extensively planted in the 

 area under several common names. Winter injury and loss varied 

 from light to severe, largely dependent upon soil moisture conditions 

 in the fall. The species has been used to a considerable extent for 

 ornamental purposes, but has been objectionable because of the 

 continual dropping of twigs and small branches. Another unfavor- 

 able feature is the usually heavy aphid infestation, which is objection- 

 able on trees close to houses. The species is recommended for 

 windbreak planting only on favorable moisture sites or on those 

 receiving irrigation. 



Salix matsudana. — This species was tested at the Mandan station 

 only, where it suffered severe winter injury almost every year. The 

 species has no possibilities for dry-land planting, but under irrigation 

 it may have some value as an ornamental because of its crooked shoot 

 growth. 



Salix matsudana f. umbraculifera. — This species was tested at the 

 Mandan station only. The tree suffered some winter injury each 

 year. The species does not appear to have any promise for dry-land 

 planting. 



Salix missouriensis. — This species is native to the area, where it 

 grows on bottoms that usually are flooded each year. The trees 

 killed back repeatedly under dry-land conditions. Suckers that grew 

 profusely from the roots of these trees seldom lived for more than 5 or 

 6 years. Behavior of the species on the bottom lands was somewhat 

 similar to that under dry-land conditions except that the stems of the 

 trees lived longer and grew to a greater height. These stems make 

 excellent fence posts that find a ready market. The species is recom- 

 mended for planting only for wood-lot purposes on sites that are wet 

 or which usually are flooded each year. 



Salix pentandra. — This species was tested in windbreaks and to a 

 limited extent as an ornamental. Winter killing and losses in stand 

 occurred most years. The species is highly desirable for windbreak 

 plantings under irrigation. It is also the most desirable willow 

 species for ornamental purposes. 



Shepherdia argentea. — This species is native throughout the area. 

 The shrubs grow along streams, in ravines, and on the north slopes of 

 hills. The species suffered heavy killing back during the severe 

 drought years of 1934 and 1936. It is highly susceptible to heart rot 

 infection caused by Fomes fraxinophilis (Pk.) Sacc. forma ellisianus 

 (F. W. Anders) Baxter. Breakage by wind and snow frequently 

 occurs as a result of this disease and brittleness of the wood. Wind 

 frequently uproots cultivated trees or twists them off at the ground 

 line. Because of this the species is not recommended for windbreaks. 

 However, it can provide good cover for wildlife throughout the year. 



Sorbus americana. — This species has been planted on a very limited 

 scale for ornamental purposes in the area. Winter injury and losses 

 occurred in most years. Stems were very susceptible to sunscald. 

 The species is of no value for planting on dry land but is a desirable 

 ornamental under irrigation. 



Sorbus aucuparia. — This species was tested at the Mandan station 

 only. It behaved similarly to S. americana, and is therefore of no value 

 for dry-land planting. It is a desirable ornamental under irrigation. 



Syringia amurensis. — This species has been planted to some extent 



