100 



Figure 3. — Overall survival of 4-year-old plants 

 by aspect for those species planted on more 

 than one aspect. 



normal from 1974 through 1978, with two exceptions. 

 August 1974 had 1.13 inches (2.87 cm) less rain than 

 normal, which could have contributed to lower initial 

 survival for some species. May through August 1976 

 had 4.5 inches (11.43 cm) more rain than normal, 

 which could have only been beneficial for plant de- 

 velopment. 



Mold on the roots and poor plant condition were the 

 primary causes of poor survival of snowbrush (9 percent), 

 silvery lupine (1 percent), and redstem ceanothus (24 

 percent). Where individuals of these species became 

 established they did reasonably well, which suggests 

 that these species might be useful for site revegetation 

 if stock was improved. A lack of nitrogen-fixing bacteria 

 in these species may have contributed to plant failure. 

 Inoculating plants with rhizobium bacteria may improve 

 plant survival. 



Curl-leaf mountain-mahogany stock was in poor 

 condition at the time of planting. It was necessary to 

 discard most of the plants, and of the few planted, 

 survival reached only 7 percent by 1978. Poor plant 

 quality and site disturbance after planting appear to be 

 the most plausible explanations for the low survival 

 rate. Plants that became established remained in good 

 condition after 9 years (fig. 4), even though this species 

 is out of its natural range in the study area. 



Initial survival of blue elderberry, black elderberry, 

 and smooth sumac was fair to good, but after 4 years 

 only 30 percent of the plants were still alive. After 9 

 years only one elderberry plant could be found. Factors 

 influencing species mortality appeared to be the hot, 

 dry slopes and the unfertile rocky soil. 



Ocean-spray was expected to perform well on the 

 test sites, but both initial and 4-year survival rates 

 were low (4 percent after 4 years). Unhealthy nursery 

 stock and poor soils may have been responsible for 

 mortality. 



■ -■• ^drefsSl 



Figure 4.— A healthy 9-year-old curl-leaf moun- 

 tain-mahogany plant provides a protective surface 

 covering and a good root system to hold soil. 

 This plant is 4 feet (1.2 m) tall and 3.5 feet (1.0 

 m) wide. 



Growth 



As a measure of success for road cut stabilization and 

 visual enhancement, transplants were expected to grow 

 and spread to provide adequate ground cover and be 

 noticeable from roadways. After 9 years. Wood's rose, 

 bush penstemon, and lovely penstemon were the only 

 species reaching or even approaching their potential 

 size at all planting sites (figs. 5, 6, and 7; table 2). 

 Many Wood's rose plants grew to a height of 3 feet 

 (0.9 m) or more and branched or spread horizontally 2 

 feet (0.6 m) in radius from the planting. Bush penstemon, 

 a low-growing, mat-forming plant, reached or exceeded 

 its expected size on many of the sites, attaining a basal 

 diameter of up to 4 feet (1.2 m) (fig. 6). Lovely pens- 

 temon, a slightly taller plant (without the basal mat-form- 

 ing tendencies) (fig. 7), reached its expected potential, 

 attaining heights of 2 feet (0.6 m) and diameters of 2 

 feet (0.6 m), even though this site is out of its natural 

 range. Red-osier dogwood developed well (fig. 8), but 

 not with site uniformity. On several sites, these plants 

 reached heights of 6 feet (1.8 m) and branched well, 

 approaching the maximum size for this species. Plants 

 on the drier cut banks did not develop as well, reaching 

 heights of 3 to 4 feet (0.9 to 1.2 m), but were likely 

 to continue growing. This species did much better than 

 expected on these sites. Red-osier dogwood is generally 

 known as a moist-site plant and to grow and survive as 

 well as it has on these south aspects is surprising. 



5 



