Wednesday Weed – Swamp Cypress

Dear Readers, the swamp cypress (Taxodium distichum) is most definitely not a weed but a stately and unexpected tree, covered in feathery lime-green foliage and bearing little round cones that look rather like medieval weapons of war. I spotted it in the Cleary Garden last week, and couldn’t wait to find out more about it. I suspect it is a tree that will be more familiar to my North American readers than my European ones, but what usually happens is that I spot a plant and then see it everywhere, so it will be interesting to see if that happens this time.

Swamp cypress is native to the south-east corner of the United States, and gets its alternative name, ‘bald cypress’ from its habit of dropping all of its needle-like leaves in autumn, following a flush of russet-red or sunshine yellow, depending on the variety. This makes it a rare deciduous conifer.  In ‘the wild’ it can grow up to 140 feet tall, though in the UK, with its cooler and less humid climate, the trees rarely top 100 feet. There are a pair of swamp cypresses in St James’s Park, and the plant as a species was thought to have been introduced to the UK by John Tradescant in 1640.

Swamp cypresses have both male and female flowers on the same tree. The female flowers are the round, green ‘cones’ (properly called ‘strobili’) in the photo below, while the male flowers are the catkin-like pendants. All in all, it looks like a tree that has created its own Christmas decorations. As time goes on, the cones will turn from green to purple, and I must make sure that I pop back in a month or so to see how the tree is changing.

The ‘shell’ of each cone is comprised of a number of scales, each of which contains four or five seeds. If the tree happens to live in a swamp, the seeds will be borne away by the movement of the water. Germination is not possible underwater, but the seeds can survive inundation for up to thirty months. If the waters subside, the seeds spring into action – they germinate from the top of the seedling, like a bean, and then race to keep their heads above water for the rest of the growing season – they can grow up to 30 inches in their first year. If the timing is wrong, and the seedling is submerged for a long period, it will die, so a fair bit of luck is involved.

Squirrels are another way that the seeds are distributed – though the animals tend to eat the outer scales, where the seeds are, they will frequently drop a few. I also noticed a pair of crows apparently trying to eat the cones on the Cleary Garden tree, so I wonder if, like jays and nutcrackers, these corvids have developed a taste for these seeds. If so, they would be another useful way of carrying the cones away from the shadow of the established trees.

Photo One by By CarTick at English Wikipedia, CC BY-SA 3.0,

Swamp cypress cones (Photo One)

A feature that ‘my’ swamp cypress didn’t have was ‘knees’. More properly known as pneumatophores, these are seen in trees that actually grow in swamps. As the name suggests, it was originally thought that these projections helped to get oxygen down to the saturated roots, but an experiment showed that the trees grew just as well with their pneumatophores removed. Other explanations might be that the outgrowths help to stabilise the tree in the soggy ground, or prevent detritus and mud from gathering around the base of the trunk, increasing the risk of rot and instability. Several of the ever-resourceful Native American tribes used the ‘knees’ as beehives. More prosaically, the early European merchants secured their sailing ships to the ‘knees’ by using them as mooring posts.

Swamp cypress ‘knees’ (Public Domain)

The swamp cypress forests of the south-eastern USA are an invaluable habitat for all kinds of animals. They are the last refuge of the Florida Panther and the striped newt, and a resting place for many migratory birds. Sadly, much as bogs in the UK are underrated as habitat, so swamps in the US are often thought of as mosquito-ridden hellholes, full of alligators. Their value to humans as a buffer-zone in the event of cataclysmic storms is often overlooked, and of course their value to the non-human members of the community is immeasurable.

Florida panther (Felis concolor coryi) (Photo from Florida Parks Service)

Photo Two by By Glenn Bartolotti - Own work, CC BY-SA 4.0,

Striped newt (Notophthalmus perstriatus) (Photo Two)

Swamp cypresses can live to an astonishing age: one of the trees along the Three Sisters Tract on the Black River in North Carolina has been estimated by dendrochronologist David Stahle to have started growing in 364 AD. However, the fight to survive to any age is a hard one: in addition to the special conditions needed to germinate and grow outlined above, the young seedlings of swamp cypress are the favourite food of the coypu, or nutria (Myocastor coypus). A group of these rodents escaped from a fur farm in Louisiana in the 1940’s and have now spread across the entire southern United States, munching as they go. In the UK the animals escaped from a fur farm in East Anglia in 1929, and it took the Ministry for Agriculture, Fishing and Forestry (MAFF) until 1989 to eradicate them: I remember seeing the body of a nutria floating in a drainage channel in Whitstable, Kent, when I was a child of about 11. However, since then a ‘giant rat’ killed in County Durham in 2012 was thought to be a coypu, and maybe there is still a population hanging out in the North of England. So often creatures are introduced, escape (or are deliberately released) and then end up being killed because they are inconvenient. It’s (almost) enough to make me despair.

Photo Three by By José Reynaldo da Fonseca - Own work, CC BY 2.5,

Coypu (Myocastor coypus) (Photo Three)

The timber of the swamp cypress has, as you might expect, a high degree of resistance to water, making it valuable for use in everything from boats to garden fencing to coffins. Prehistoric swamp cypress wood is also prized for carvings – a well-preserved stand of trees over 50,000 years old was discovered by divers several miles off the coast of Alabama in 60 feet of water. It was thought that maybe Hurricane Katrina had removed the underwater sediments that had hidden the grove for all these years. When cut, the branches still smelled of cypress.

Some prehistoric wood was infected by a fungus that created distinctive oval-shaped discolourations in the timber. This type of wood, known as ‘pecky’, is highly prized for panelling and flooring.

Photo Four from

‘Pecky’ panelling and ceiling (Photo Four)

All in all, my little Cleary Garden tree is clearly a baby as far as swamp cypress go. I cannot resist sharing with you this wonderful photo from the Arborday blog, showing what it could be in the right environment. Sadly, street trees rarely have the chance to achieve their full potential, what with the compacted soil, the pollution and the constant pollarding.

Photo Five from

Photo Five

And of course, here is a poem, this time by Ann Neuser Lederer, originally from Ohio, who is a Registered Nurse and who has also studied anthropology and art. It speaks to me because I am learning a bit about hope, and the way that the future is always unknowable.  I think that ‘my’ swamp cypress might be a tree to watch through the seasons, and the years, a kind of mooring post for me during this time of change. Let’s see.

Bald Cypress by Ann Neuser Lederer

Mistaken for dead or dying.   
At first hint of chill: brittle, orange alarm.

In a burst of turbulence, the wounded umbrella flipped.  
Skyward, then reverted, cured, surprised as Lourdes. 
Abandoned canes and crutches piled beside the marble steps. 

At the playground, while we were busy ringing giant chimes,
a silent little boy appeared.
Sat near and stared, then broke into wails.  
A siren signal: danger.
Soon his custodian snatched him away.
Diverted, and the incident forgotten. 

Do you remember the long, slow, goodbyes?   
Waving and waving until the vision dims?
How much longer before he wanders away for good?

Deciduous evergreen sprouts. Soft, gentle feathers,
hopeful, tender, pastel nursery green.
The Cypress, seemingly done for, after its long cold sleep
remembers to return.  


Photo Credits

Photo One by By CarTick at English Wikipedia, CC BY-SA 3.0,

Photo Two by By Glenn Bartolotti – Own work, CC BY-SA 4.0,

Photo Three by By José Reynaldo da Fonseca – Own work, CC BY 2.5,

Photo Four from

Photo Five from



8 thoughts on “Wednesday Weed – Swamp Cypress

  1. Sarah

    I know these trees well, they are not uncommon in parks and gardens around here. I wonder if parakeets also eat the cones. I watched them efficiently demolishing sweet chestnuts, from the treetop walkway at Kew last weekend.

  2. tonytomeo

    There are two at work. I likely mentioned them last time. One was planted intentionally next to a lawn with saturated soil not far below the surface. The other was planted next to a stream, but was supposed to be a dawn redwood. Even though the specimen that was planted intentionally is beginning to develop knees, we like it too much to cut down. If the knees and buttressed roots get to be a problem, we might just landscape around it so that the area is not used for anything. The other specimen is likewise too cool to get cut down. It looks weird among the redwoods, including a dawn redwood, but we like it too much. They are rare here.

    1. Bug Woman

      They are gorgeous, gorgeous trees (the swamp cypress and the dawn redwood). I think I might visit the swamp cypress down the road from me to see if it has any fall colour yet.

  3. Pingback: The Search for Green Part Three | Bug Woman – Adventures in London

  4. Pingback: Hope in The City | Bug Woman – Adventures in London

  5. Pingback: Bugwoman’s Annual Report Part Two | Bug Woman – Adventures in London

  6. Pingback: A Short, Wet Walk in St Pancras and Islington Cemetery | Bug Woman – Adventures in London

Leave a Reply