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Island Alum Root

Heuchera maxima

Heuchera maxima in full bloom April 2011. Photo: SK Reid.
Heuchera maxima in full bloom April 2011. Photo: SK Reid.


Island alumroot is an attractive herbaceous perennial California native, even when not flowering. Like many plants in this category, its overall appearance improves with age and its bloom in the trials field during the spring of 2011 was impressive. The flowers hold for a long period of time and are an attractive rosy color for many weeks after they dry. There were no significant differences in growth indexes between treatments, making this plant a desirable choice for dry shade.

Master Gardener recommendations were mixed with this plant. It was a target for deer and rabbit browsing in some areas. Santa Clara found it unexciting, and an uneven performer throughout the year, and would not recommend it for their area close to the coast. Riverside did not provide adequate shade or water to establish it. It was recommended, however by gardens as diversely situated as Nevada and Orange Counties, given proper cultural care.

Basic Info

Submitted by: UC Davis Aboretum
Trial Exposure: 50% Shade
Year evaluated: 2011
Height & Width
(after 2 years):
15" x 40" - UC Davis
Reported Height & Width
(at maturity):
1' x 1-2'
WUCOLS plant type: P N A
Water Needs & WUCOLS Region:
Low - Region 2 
Mean Overall 
Appearance rating:
(1-5 Scale, 5 is highest)
4.0 - UC Davis 
Flowering Months
April-June - UC Davis

Growth and Quality Data

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