Rhaphiolepis umbellata 'RutRhaph1'

Summary

South Coast Research & Extension Center (South Coast REC/SCREC) is located in Irvine California, this site has a sandy loam soil and plants are irrigated with reclaimed water. UC Davis is located in Davis, California, this site has a silty clay loam soil and plants are irrigated with potable water. More information about the field sites is located in the Nuts & Bolts section.

Southern Moon® is a small shrub with deep green foliage and coppery new growth. As with several other plants evaluated in both sites this year, Southern Moon® grew much larger at South Coast REC and outperformed those at UC Davis. Southern Moon® was one of the top three highest rated plants as measured by overall appearance scores at the South Coast REC spring open house, where participants responded positively to the foliage quality and remarked on the disease resistance relative to other Rhaphiolepis cultivars they knew (Table 14d).

At UC Davis there was no difference in growth between treatments (Figure 9b). Unfortunately, plants in all three treatments declined in growth over the season, with only seven of 24 plants showing positive plant growth relative to their April size. Over the same period, mean overall appearance scores for each treatment declined as well, with no statistical difference between the treatments. A significant difference in disease resistance was observed between the high and low treatments, (the low treatment showed more resistance), but this difference was outgrown during the heat of summer (Table 14a). Researchers observed spotting and necrotic leaf tips that resembled Entomosporium leaf spot early on, but new growth covered most of it by July. Based on our results we recommend irrigating Southern Moon® on low water in WUCOLS zone 2.

At South Coast REC there was a significant difference in relative growth rate between the high and low treatments, beginning in July and continuing for the remainder of the trial period, indicating a strong treatment effect (Figure 9d). The early difference in growth rates between moderate and low treatments was outgrown by August. Quality differences were observed between the high and low treatments in the vigor and overall appearance categories (Table 14c), and by October several plants on low water were showing drought stress symptoms yielding an additional difference between the moderate and low treatments. Due to the differences in performance between the high and low treatment, our data indicates this is not a low water use cultivar in sandy soil when using reclaimed water, even with a leaching factor. However, differences between the high and moderate water treatments were insignificant, and the aesthetic ratings between these treatments were comparable.  We therefore recommend growing Southern Moon® on moderate irrigation in WUCOLS zone 3.

Growth and Quality Data

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