Hydrangea paniculata 'Renhy'

Summary

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.

Vanilla Strawberry™ gets its name from its blooms starting out white and fading to light pink, eventually turning deep pink with a sepia tinge. Plants were pruned in February 2018 and 2019 in accordance with common horticultural practices. In our consistent light shade, these plants had an open, loosely fountain-form shape especially when the large, heavy blooms weighed the branches down.  It’s possible that full morning sun and afternoon shade may have produced a denser form. In the spring, new stems were colored red with similar appearance to Cornus sericea (red osier dogwood). Flowering began in mid-June and peaked in July 2019, with high floral display scores maintained through September 2019 due to the continued interest provided by the changing colors of the bloom rather than new blooms (Table 22a). Though some flowers remained in October, they ceased to provide floral impact. Based on mean overall appearance scores at the open house, participants found Vanilla Strawberry™ acceptable to good at the spring and summer open houses, scoring equally as well at each event. Although this plant did not score as high on the ratings as other plants at the open house in summer (Table 22b), more participants nevertheless listed it as their favorite at the summer open house by a wide margin (21 votes, 46 participants). Its charming blooms and lovely color won them over.

A significant difference between the relative growth rates of the high and low treatments was observed beginning in July, showing that, even in shade, this is not a low-water plant. Over the deficit season, differences in overall appearances between all treatments were significant (Table 22a). 

Floral quantity ratings of the high and moderate treatments are notably different from the low rating. Based on comments collected during the aesthetic ratings, the low treatment appeared to produce smaller flowers than other treatments, though this was not something we measured. Significant differences in vigor, foliage quality, and overall appearance of the high and moderate treatments compared to those qualities of the low were observed from July through October. By the end of the season the plants on the low treatment were noticeably stressed. We recommend Vanilla Strawberry™ be irrigated on high water in WUCOLS region 2 for best appearance, though acceptable health and flowering may be experienced on moderate irrigation. 

Growth and Quality Data

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