Dawn redwood grove along a stream at Morris Arboretum.
Then it occurred to me that he meant my dawn redwood (Metasequoia glyptostroboides). I assured him that the tree was fine, that it had just gone dormant for the winter and would leaf out again in spring.
Along with larch (Larix spp.) and bald cypress (Taxodium spp.), dawn redwoods are deciduous conifers that drop their needles in fall, just as deciduous broadleaf trees such as maples, crabapples and elms drop their leaves. The term "conifer" means cone bearing, but is sometimes mistakenly used to indicate a plant that is evergreen.
Dawn redwood is a truly ancient species that was known in fossil records from as far back as 65 million years ago, but thought to be extinct until it was found growing in the wild in China in the early 1940s. They were one of the most widespread trees in the Northern hemisphere during the Tertiary Period (part of the Cenozoic Era), although they are not considered native to North America today.
The Arnold Arboretum underwrote an expedition to China in 1947, where seeds were collected and distributed to botanical gardens and arboreta around the world. When China and the United States began diplomatic relations in 1972, botanists and horticulturists soon followed to collect more seed in order to diversify the genetics of dawn redwood. Until then, all the dawn redwoods growing outside of China came from the seed collected by the Arnold Arboretum in 1947, which represented a fraction of the genetic diversity of these trees.
Dawn redwood is no shrinking violet, growing 70-100 feet tall with a 15-25-foot spread. And it attains size quickly, capable of growing 50 feet tall in 15-20 years; unlike many fast-growing trees, dawn redwood is a sturdy tree. It is has a strongly pyramidal growth habit with a single central leader. Perhaps its most striking feature is its heavily buttressed, fluted trunk, clothed in reddish-brown bark that darkens with age. The opposite to sub-opposite foliage emerges bright green and matures to reddish-orange to russet-brown in fall. It has a very soft texture.
Dawn redwood grows best in moist, well-drained, slightly acidic soil and full sun. It tolerates moist areas, and is quite striking when planted along a stream. It has few serious insect or disease problems, although Japanese beetles can damage the foliage and a canker disease has been reported.
This is a tree that needs room, so dawn redwood should be reserved for large properties, parks, university and corporate campuses, and golf courses. Plant as a specimen, in groves or allées, or use in large rain gardens.
- 'Ogon' and 'Gold Rush' - These gold-foliaged dawn redwoods may be the same tree with different names. The new growth is especially bright gold. Growth is slower and the ultimate size smaller than the straight species due to the lower chlorophyll content of the leaves.
- 'National' - A selection made at the U. S. National Arboretum for its very narrow, upright growth habit.