Sequoiadendron giganteum Seeds | Giant Sequoia
LATIN NAME: Sequoiadendron giganteum
COMMON NAME: Giant Sequoia, Sierra Redwood, Big Tree
Plant Profile
The giant sequoia is the most massive living tree on earth, and while it is easy to plant, it is almost impossible to garden around. It grows to sixty or ninety metres, with a trunk up to eight metres across at the base, and the bark alone can be sixty centimetres thick, soft, fibrous, reddish-brown and almost incombustible.
The crown is narrow and column-like in youth and becomes irregular and broken with age. The foliage is scale-like, blue-green, and smells of resin when crushed; the cones are small, egg-shaped and persist on the tree for years. The species is native to about seventy groves on the western slope of the Sierra Nevada in California, where it grows in deep, granitic, well-drained soil at fourteen hundred to twenty-four hundred metres, in a climate of heavy snow and dry summers.
Science & Biotechnology
The tree’s biology is organised around fire. Thick, tannin-rich bark insulates the cambium, the lower branches shed cleanly, and the wood resists decay; a mature tree can survive fires that kill everything around it. Reproduction, though, needs fire: the cones dry and open after heat, and the seed germinates best on bare mineral soil cleared of litter and competition.
Without fire, seedlings fail under the parent trees, which is why fire suppression in the twentieth century caused a recruitment gap that managers now work to correct with controlled burns. The species is also one of the fastest-growing conifers in its early decades and one of the longest-lived, with ring counts exceeding three thousand years. Its genome was sequenced in 2020 and shows an unusual expansion of genes associated with disease resistance and wood formation.
Uses & Benefits
Giant sequoia is planted as a specimen and an avenue tree in parks and large estates across Europe, where it has been grown since the 1850s, and it makes an effective windbreak in the right climate. Its timber is light, brittle and resistant to decay, and was used for fence posts, shingles and grape stakes, but the wood shatters easily and the tree is too valuable standing to be cut for lumber.
Its main contemporary value is in conservation and carbon storage: an old grove holds more biomass per hectare than almost any other forest type, and individual trees store carbon for millennia. In a garden it is a tree for a park, a large lawn or a boundary, not for a suburban plot, and it should be sited with its eventual width in mind, since the roots run wide and shallow and the shade is deep.
Growing from Seed
Seed germinates readily after four weeks of cold, moist stratification, and light improves the result, so surface-sow onto a peaty, gritty mix and press in without covering. Keep the pot at about eighteen degrees and evenly moist; germination takes two to four weeks.
The seedlings are tiny and slow at first and need protection from damping off, so use clean compost and good airflow. Grow them on in deep pots for two years, then plant out in autumn into deep, well-drained soil in full sun, with shelter from the worst wind while young. The tree’s roots are shallow and wide, so keep a clear radius around the trunk and never compact the ground within its spread.
Our Take
The largest tree on earth, easy from seed and impossible to ignore; plant it only where there is room for a monument.
Related Reading
If Giant Sequoia appeals to you, these related plants are worth a look: