Rosa 'Meiradena'

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.

UC Davis Trial Results - 2017

Icecap is an extremely floriferous shrub rose that achieved better overall appearance ratings on the two higher irrigation treatments only during the hottest month of July (Table 13a). There were no significant differences in growth between treatments and no other treatment-related quality ratings were seen. This shrub rose’s one flaw is that the white blooms turn parchment colored and remain on the plant for too long without self-cleaning. Because the plant is so floriferous, the number of clinging dead flowers can be significant and were the only detrimental comment. Fortunately, there was always some floral display on the plants and combined with disease-free foliage and an overall good rounded habit, the plant consistently achieved good to very-good appearance. Even the lowest irrigation treatment put on a late season flower show.

Icecap was warmly received by Open House participants, posting respectable scores in both May and July. The ratings in September show a difference in scores between the treatments in that month, which can be attributed to the blooming pattern for this cultivar (Table 13b). Raters encountered plants on the highest treatment as they were finished blooming and many of the flowers had faded and not yet dropped. When the plant is in full bloom participants noted it is “impressive.” However, they noted that this cultivar held on to spent blooms, perhaps longer than the other cultivars tested, a condition that was “not appealing.” Regardless of the Overall Appearance scores in September, as a cultivar, participants continued to list Icecap as one of their favorite plants as it was “attractive, healthy, vigorous with loads of flowers”, had “great structure”, and “in general the foliage was very clean.”

South Coast REC Trial Results - 2019

Icecap™ is a shrub rose purported to be a competitor for Rosa ‘KORbin’ Iceberg. Icecap™ has a handsome, rounded, dense form with eggshell white, almost cuplike rosette-shaped blooms which fade to sepia and hold on the plant a long time before shattering (Figure 31). Icecap™ bloomed throughout the season with peak bloom in May. Shrubs were virtually smothered in blooms in May with mean floral display ratings of each treatment ranging from 4.4 to 4.8 (1-5 scale, 5 is highest). A second flush occurred in July, albeit with lower mean floral display ratings ranging from 3 to 3.7 (Table 17a). All plants had at least one flower open each time researchers rated them. Its tendency to hold on to dead flowers, however, was a notable detractor from the overall appearance. Researchers cut back the plants to 1/3 size in February 2019. The only significant difference in subsequent relative plant growth index observed was between the moderate and low treatment in October. However, there were only minor differences in quality between the treatments until October, and we recommend irrigating Icecap™ on low to moderate water in WUCOLS region 3 if using reclaimed water.

Growth and Quality Data

Click Here for Complete Data Set - UC Davis

Click Here for Complete Data Set - SCREC