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Heuchera maxima

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About Island Alum Root (Heuchera maxima) A species of flowering plant in the saxifrage family known by the common names island alumroot and Jill-of-the-Rocks. It is endemic to three of the eight Channel Islands of California, where it grows on cliffs. It is rare in the wild due to its limited distribution. It is also cultivated as an attractive garden plant, valued for both its foliage and flowers. This is a rhizomatous perennial herb growing a broad patch of large, rounded, multi-lobed green leaves with long leaf stalks and a fringe of hairs along the edges. It produces an erect flower cluster up to 60 centimeters tall with many clusters of tiny, hairy flowers. Each flower is rounded with fleshy white or pink lobes and tiny petals curling away from the center. The protruding stamens are tipped with large anthers.

It performs best in coastal gardens where it can take full sun to part shade. In inland gardens it may require full shade and additional water. It looks good in woodland gardens.
Plant Description
Plant Type
Perennial herb

Max. Height
1 - 2 ft (0.3 - 0.6 m)

Max. Width
2 ft (0.6 m)


Growth Rate


Flower Color
Pink, White

Flowering Season
Spring, Winter

Native Status
Natural Setting
Site Type
Chaparral or coastal sage scrub on rocky or sandy cliffs and sea bluffs of the northern Channel Islands

Full Shade, Part Shade, Sun

Elevation ?
38' - 6918'

Annual Precip. ?
11.7" - 29.4"

Summer Precip. ?
0.15" - 2.72"

Coldest Month ?
37.8° F - 55.6° F

Hottest Month ?
59.0° F - 70.4° F

Humidity ?
1.36 vpd - 15.81 vpd

Soil Description
Prefers sandy/rocky soil with good drainage

Soil PH
6.0 - 8.0

Fast, Medium

Cold Tolerance(° F)
Tolerates cold to 12° F

Companion Plants
Use with other island species such as: Trees - Island Ironwood (Lyonothamnus floribundus ssp. asplenifolius), Island Cherry (Prunus ilicifolia ssp. lyonii), Island Oak (Quercus tomentella) Shrubs and herbs - Island Ceanothus (Ceanothus arboreus), California Encelia (Encelia californica), St. Catherine's Lace (Eriogonmum giganteum), Santa Rosa Island Sage (Salvia brandegeei), Manzanita (Arctostaphylos species), Dudleya species, Yucca species

Wildlife Attracted
Hummingbirds love the flowers

Landscaping Information
Ease of Care
Very Easy

Water Requirement ?
Very Low, Low
Extremely Low
Very Low
Moderate - High

Moderately Popular

Max. Summer Water ?
No Summer Water
Keep moist

Deep Organic

Propagation ?
For propagating by seed: No treatment.

Common uses
Groundcovers, Hummingbird Gardens, Bird Gardens

Nursery Availability
Commonly Available

Other Names
Common Names
Jill Of The Rocks, Jill-of-the-rocks, Island Alumroot

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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