A darling of the small stature understory flowering trees in Northern California may be replacing the ever-popular flowering but fruitless cherries, plums, and crabapples due to durability in a changing climate. For their part, flowering fruit trees are wonderful, but I have observed more challenges, primarily drought and sun scald, to their performance. For small-scale flowering trees, the genus Cercis offers a few alternatives to other less tolerant species.
Cercis canadensis has lush, heart-shaped foliage, which emerges after their striking lavender or white spring blooms. Their flowering sets the tone for shedding winter darkness. Its classification under the Fabaceae family should tell readers a bit about the flower and fruit; Fabaceae members are legumes, which gives them a sweet pea-like flower followed by persistent pods that can hang on the tree throughout fall and winter. Depending on the viewer, the pods can appear either attractive or unsightly, which might be the only drawback to this tree.
The species epithet, canadensis, and common name, Eastern redbud, provide hints to its origin and characteristics. As a native to North America, it performs best with regular water and tolerates winter cold and summer humidity...what we would find in the Eastern United States. Generally, redbuds of all kinds will have very small flowers hugging close to the branches; even when they are fully open the flowers look like buds ready to burst open but in fact have already done so.
Eastern redbuds are also tolerant of most soils providing they have a modicum of moisture, and this is where there could be challenges as drought in California continues. I have not seen sources discuss their drought tolerance. Instead, Cal Poly’s SelecTree, for example, only states that they bloom best in full sun with regular soil moisture. Providing supplemental irrigation throughout the year will promote healthy performance long-term, and since it tolerates clay soil, moisture retention might be easily provided here in Northern California.
California has a native species called Cercis occidentalis, or Western redbud. I won’t elaborate here, but our western species is indeed drought tolerant and can handle adverse conditions. Unfortunately, as a tree the resulting growth is unreliable. Under its ideal conditions, C. occidentalis will become a full-sized tree or large shrub. All too often, I have observed their unpredictable and even short-lived performance. They, too, will produce an abundant spring bloom followed by persistent seed pods.
Interestingly, a recent edition to the Royal Horticultural Society's The Garden notes that double flowering C. canadensis do not produce seed pods "perceived in the USA to be 'messy'," which might be a desirable trait leading to less clutter and mess to clean up (p. 56, April, 2022). While the article is not specific about other cultivars, the author and Oregon based tree nursery, J. Frank Schmidt & Sons, Co. list C. canadensis ‘Pink Pom Poms’ as a double flowering redbud. Below are a number of additional cultivars found in various U.S. and overseas sources.
There is another Cercis that Californians should explore, C. griffithii, or Afghanistan redbud. Not easily found, but sources note its drought tolerance. If anyone reading this has one, please share your experience with growing it. As of this posting, I found a description on Annie's Annuals but no link to availability.
Cultivars
'Ace of Hearts' - Tighter growth on a small stature, the foliage is dense requiring minimal pruning. Few seedpods if any.
'Alley Cat' - What a fun name! A clear winner for an understory planting, this cultivar has variegate green/white leaves that will brighten a dark space.
'Forest Pansy' - A popular purple leafed variety offers great contrast to bright greens. Its purple coloring can have a bit of green, whereas cultivars 'Merlot' and 'Ruby Falls' might be more consistently purple.
'Hearts of Gold' - New growth starts yellow but will turn yellow-green over the summer.
'Litwo' - This name apparently is an abbreviation for "Little Woody," describing its smaller size. As of this posting, it does not appear to be available in the United States yet.
'Merlot' - This is a unique cross between 'Forest Pansy' and another variety, C. canadensis var. texensis, which is noted for a little more drought tolerance. 'Merlot' also has purple leaves.
'NC2016-2' - Better known as Eternal Flame was voted 2021 Royal Horticultural Society Plant of the Year and is a notable cultivar bred by Dennis Werner of North Carolina State University and the JC Raulston Arboretum. The foliage offers a riot of color, starting purple when young becoming a golden yellow at maturity but then changes again to chartreuse toward the end of the season. Compact form.
'Nccc1' - Also known as Carolina Sweetheart, this cultivar has the most unique foliage with splattering of pink, white and green.
'Pink Pom Poms' - A fully double flower, noted to not produce seed pods. Another breed from NC State University and the JC Raulston Arboretum.
'Ruby Falls' - As the name suggests, this cultivar has a weeping habit, lending itself to Japanese styled gardens. Its purple leaves appear to be larger than those found on 'Forest Pansy', but this characteristic should be verified.
'Vanilla Twist' - White flowers and a cascading form.
Check out the many other cultivars developed at JC Raulston Arboretum here and a longer list at the United States National Arboretum.
West Valley College Campus Location: Cercis canadensis 'Forest Pansy' (shown below, second photo)
Administration / President's Office (West raised planter)
Lat: 37°15'50.54"N
Long: 122° 0'39.67"W
facts
Botanical Name: Cercis canadensis
Cercis: Greek, kerkis, which references the seed pods appearance as a weaver's shuttle
Canadensis: From Canada, however the species origin could include Eastern United States.
Common Name: Eastern redbud
Family Name: Fabaceae
Origin: Eastern North America
design considerations
Positioning: Wooded areas and lawns, small spaces (pending cultivar selection)
Garden Themes: Pollinator, woodland, children's, culinary, courtyard
Uses: Small-scale street tree, edible flowers, specimen, understory tree, wildlife (USDA lists this species' seed pods as important to Eastern U.S. quail, pheasants, goldfinches, and other birds and deer.
identifying characteristics
Type: Deciduous tree, standard or multi-trunk, small to large shrub
Form: Round
Texture: Coarse
Size: 25' tall by 25' wide (varies by cultivar)
Outstanding Feature(s): Flower, fruit, leaf color (by cultivar and season)
Bark: Dark brown to dark red, can be smooth to scaly
Leaf:
Type: Simple
Arrangement: Alternate
Shape: Cordate
Margin: Entire
Color: Dark to medium green turning yellow in autumn (Cultivars vary)
Surface: Glabrous
Flower: Late winter to early spring. Umbel may be tight to the branch or slightly pendulous. Pea-shaped, possibly fused petals. Pending cultivar, various shades of pink, lavender, or white
Fruit: Summer to winter. Persistent and prominent legume pods may dry while still attached to the limbs. Reddish brown up to 4" long.
cultural requirements, tolerances & problems
Sunset Zones: 1-24
USDA Zones: 4-9
Light: Full sun to partial shade
WUCOLS SF Bay Area Hydro Zone: Moderate
Soil:
Texture: Sand, loam, clay, well composted
Moisture Retention: Well-drained. Tolerates brief dryness
pH: Highly acidic to highly alkaline
Tolerances: Soil compaction, black walnut leaf matter, dear, fire (may regrow from base)
Problems: Persistent fruit, may be short-lived
Branch Strength: Medium
Insects: Caterpillars, scale
Disease: Anthracnose, crown rot, armillaria, phytophthora
citations & attributions
Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.
Extension Gardener. "Cercis canadensis." North Carolina State University, Raleigh. Accessed on June 20, 2022, from https://plants.ces.ncsu.edu/plants/cercis-canadensis/.
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
Plant Finder. "Cercis canadensis." Missouri Botanical Garden, St. Louis. Accessed on June 22, 2022, from https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=280440&isprofile=1&basic=Cercis%20canadensis.
SelecTree. UFEI. "Cercis canadensis Tree Record." 1995-2022. Cal Poly State University, San Luis Obispo. Accessed on June 22, 2022, from https://selectree.calpoly.edu/tree-detail/312.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on June 22, 2022.
Photos:
All photos by TELCS.
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