I was nuts about extinct animals when I was a kid. I desperately wanted them to reappear. I deeply regretted the demise of the dodo bird and passenger pigeon, and spent days sulking because I’d never see a woolly mammoth traipse through my backyard. I hoped scientists were wrong and that these beasts were somewhere off frolicking with saber-toothed tigers in faraway, undiscovered places.
Once I added flora to my list of curiosities, I was forced to confront the realities of extinction again. Imagine my delight when I learned that a once-thought-to-be extinct tree named Metasequoia glyptostroboides had reappeared on the botanical radar. Fifteen million years ago, dawn redwood grew in many parts of the world, including North America. But until its rediscovery in China during the 1940s, we only knew of dawn redwood’s existence from fossil records.
Although this deciduous conifer now thrives in many American landscapes—especially out West where they are so numerous they are often taken for granted—we have mostly ignored dawn redwood in the Southeast. But if bald cypress (Taxodium distichum) is on your wish list—and you’re reluctant to plant one because it sends up root-like spikes, called knees, around the base of its trunk— dawn redwood offers a reliable, appendage-free alternative.
While there are about 550 species of conifers, which are defined as cone-producing trees with evergreen needles, only five are deciduous, meaning that they annually shed their leaves. One member of this quintet, ginkgo or maidenhair tree (G. biloba), doesn’t even look like a conifer at all and displays flat, fan-shaped leaves that turn brilliant yellow in autumn. The other four: dawn redwood, pond cypress (T. ascendens), bald cypress and larch (Larix spp.) look more like soft green, feathery pine trees. Their needles turn a brilliant rust color each autumn before blanketing the surrounding ground with a layer of velvety, teddy-bear brown, no-cost, low-maintenance organic mulch.
Although the horticultural differences of those four are slight—it’s mainly a question of mature height and growth rate—larch will not survive in Charleston gardens. It needs Arctic-like temperatures found in the upper Midwest, New England, most of Canada, Northern Europe and Siberia.
So why should Southerners go to the trouble to plant a nonnative, deciduous conifer when we already have two perfectly acceptable indigenous ones (pond and bald cypress)? After all, bald cypress is admired for its willingness to grow in urban settings because it’s nonchalant about hot pavements. Yet dawn redwood offers shade in the summer and opens to sunshine during winter. It ignores both drought and prolonged exposure to moisture.
While these merits also apply to its Chinese cousin, dawn redwood has an additional advantage in cityscapes—no knees. Despite the fact that these appendages on bald and pond cypress are legendary, no one has yet explained their botanical purpose. Even though some horticulturalists contend that cypress knees are not as prolific in urban settings, these root-like shoots occasionally pop up, causing potential hazards. A sharp pruning saw keeps them at bay, but dawn redwood requires no such attention.
Bald and pond cypress grow more slowly than dawn redwood, usually adding an additional 18 feet in around 20 years (the standard for average annual medium growth rate is 13” – 24”). Dawn redwood is slightly more robust, adding about 2 feet per year to its height. While our native cypresses can reach climactic heights of around 100 feet, dawn redwood grows an additional 20 feet taller, placing its visual impact on a much grander scale than bald or pond cypress.
Dawn redwood’s wintertime silhouette is also striking. Its straight-arrow single trunk zooms upward through a pyramid of mostly bare limbs, enticing raptors, such as Cooper’s and red tail hawk, to perch atop dawn redwood’s soaring height. (Larch shares this linear aspect, and Scottish tall ship builders were once well known for making masts from larch.)
Perhaps the only downside to planting a dawn redwood in a Lowcountry landscape is its low tolerance to salt spray, making it unacceptable for beachfront property. (On the other hand, bald and pond cypresses are moderately tolerant to sea air and their self-mulching feature adds much-needed organic material to sandy soils.)
A bright lime green variety of dawn redwood named ‘Ogon’ (USDA Hardiness Zone 5 – 9) is found at local garden centers in 5-gallon containers. Other cultivars are available, including one named ‘Emerald Feathers’ (USDA Hardiness Zone 5 – 9), which has a reputation for exceptional durability. ‘Gold Rush’ (USDA Hardiness Zone 3 – 10) leans toward yellow hues and turns shades of orange before shedding needles in autumn. Of course, the straight species, simply called dawn redwood (USDA Hardiness Zone 5 – 11), is also available. If your favorite nursery does not have your preferred cultivar in stock, request a special order. Most establishments are happy to oblige.
PJ Gartin is a freelance garden writer who lives in Charleston.