(Much of the body of the following text comes from an earlier HPSO Bulletin article)
Visual artists employ all sorts of little tricks to create an impression. A painting is an abstraction; it is not the place or thing that it portrays. As viewers, we respond to the visual cues we are given and our imaginations take us to a place. We don’t just see a flat piece of canvas and paint. As members of a civilized society, we share a set of tools that engage when we see a picture and we read it. A successful artist manipulates this visual language and shows us what we would otherwise never have imagined.
As an art form, landscape design is much the same. A designer who understands the cues that we respond to can take a visitor to another place. Unlike a painting, we can walk around and/or through this creation. It grows and changes seasonally and over the years. Even the quality of light will affect our experience. Whether we have been to a place or not, we have seen enough pictures, television programs and movies, read enough articles and books to have created an idea of what these places may be like. The designer taps into this language and, given the limitations of scale and climate, creates an alternative world that neatly fits within our shared larger world that is Portland and the Northwest.
The cues the designer employs need not be the genuine article, in fact this may be impractical or impossible. Because there is a wide richness of plant forms shared amongst the regions of the world, we can find a plant that possesses similar characteristics that will work. This plant then allows us to build an image and experience.
The Chinese windmill palm, Trachycarpus fortunei, is not a tropical, but it shares enough in common with many true tropicals that when we see it in the landscape, we prepare ourselves to believe that we could be there, especially if it shares space with other plants that have the color, texture, form and scale of plants we think of as tropical. Chinese windmills come from the mountains of southern China. Snow is not uncommon to their land of origin. They come from cool, damp, mixed forests where they share space with conifers. Sound familiar? And they are not unusual for Portland, having been grown here for many decades.
The genus Trachycarpus, of which there are ten or so species, with more being described, can be found across the lower Himalayas of northern India, Nepal and east through Myanmar, northern Thailand and China. Trachycarpus fortunei is one of the fastest growing palms for our climate. The three in Waterfront Park’s Columbia Circle were planted as five-gallon plants around 2001. Another species, T. takil, is arguably even more cold tolerant, though its validity as a species is in question. What ever its name, some prefer this form because its trunk is much smoother as it does not possess the coarse fibers that cover T. fortunei. I planted mine, around 2011, in the 5 Flags planter next to the river in front of the Riverplace Hotel. All Trachycarpus are of the palmate group whose fronds have many narrow deeply-divided segments that radiate from a single point at the end of a stem. In general the group of Palms recognized as a ‘palmate’ are, overall, more hardy than the others. Please also note that there are more than 2,500 different species of palm in the world, the vast majority of which we can’t grow here in Portland, OR.
All palms are monocots. This means they share at least as much with tulips, lilies, grasses and bananas as they do with maples or fir trees. Palms don’t have bark or the cambial tissue that creates it, which adds wood and girth to a maple or fir’s trunk. You can’t girdle and kill them with a string trimmer, this is evidenced by all of those Palms growing in resorts with grass growing right up against their bases. These trees often display string trimmer blight, but don’t suffer from it. Instead they have a uniform, unringed, woody cortex, scattered within which are hardened conducting vessels, phloem and xylem, carrying water and nutrients between the roots and foliage. Palms have one growing point from which all their growth emerges. They do not branch, ever. If you cut the top back, you kill the tree.
A young palm seems to grow slowly. Their growth appears to stall for a few years, but it hasn’t. During this period the plants grow their bases broader, including their meristematic tissue, adding girth without height. (Young palms are less cold hardy than mature trees because the meristem, the growth point, has less woody cortex surrounding and insulating it.) At a certain point the trunk, having reached much of its maximum diameter, begins to extend. The roots as well do not branch, all of them originate from the base not unlike an old kitchen mop.
The foliage emerges from the top of the trunk vertically as fuzzy spears, all of the segments folded tightly, accordion like. As the spear extends, the fans open and gravity and the continuing extension of the trunk push them over, eventually, into a horizontal position. They are arranged evenly around the trunk forming an overall rounded crown. As an evergreen, the fronds persist for several years green, busily photosynthesizing, while the growing tip leaves them below. The foliage on all Trachycarpus persists hanging on long after it is dead loosely around the trunk (Some palms are self pruning, dropping their foliage cleanly when the reach the end of their productive lives.) Cutting is required if you want to avoid the skirts that would other wise clothe them. These are also subject to wind damage folding or breaking down the petioles disrupting their perfect radial pattern. In some areas these dead ‘aprons’ can, such as on California’s similar though more grand Washingtonias, provide ‘harborage’ for rat populations. The petioles on all palms are quite hard especially if they have dried and browned completely. They then are not easily snipped.
All Palms go through a juvenile phase as suggested above. In the initial part of this the leaves are very different than the mature foliage. The juvenile foliage of all Palms is very similar regardless of which species or even genus the tree is. It unfolds as little pointy canoes ribbed lengthwise with up-turned bows and sterns. Over time the newly emerging leaves begin to take on characteristics of the their mature form. It can take many years in some species, i.e., genus Sabal, for their foliage to take on its full mature form and size. There is a transition period where the foliage expands and begins to split before throwing fully mature fronds. The palmate palms, like the Trachycarpus, have mature fronds whose segments all radiate from their point of attachment with a long and hard petiole. The outline of the frond, its breadth and color, the depth of its corrugations and its number and length of its segments all vary between species. Pinnate Palms, like my Butia capitata and Date and Coconut Palms have a rachis down the middle like any other pinnate plant with its leaflets arranged ‘feather’ like on either side. Costa-palmate are kind of a mixture of the two, but to the untrained eye, they may look like just another palmate leaf.
Because of all of this Palms all attain mature canopies when they are quite stubby and are still low to the ground. Over the years, the trunks lengthen (not all Palms form above ground trunks and so don’t become ‘trees’) while the canopy remains essentially the same diameter. Remember they do not branch. They can become quite tall and ‘leggy’. There is a Wax Palm native in the mountains of Columbia that can grow over 200′ tall while it retains the same simple canopy form and size. There is also the Chilean Wine Palm, Jubaea chilensis, that grows to 100′ with a stem that can be 5′ in diameter, a diameter it had when it likely had only 10′ or so of trunk length. One needs to keep this in mind when planting out next to paths, patios etc. Eventually the canopy will clear the space, but may likely crowd you.
The flowers, of which there can be thousands in a single inflorescence, emerge annually just below from where the frond spears stretch up. On most Palms flowering may strike the temperate gardener as odd emerging directly from the trunk. Each species is slightly different. On Trachycarpus fortunei they emerge in spring held tightly in creamy yellowish clumps that look somewhat like what I picture as lungs might before they expand. Palms are monecious, each plant producing only male or female flowers. Trachycarpus females will ripen fruits that look much like juniper berries, at the same time they are flowering, the following spring. In the irrigated garden many of these will germinate on the ground in Portland. Both the male and female inflorescences dry up, harden and persist on the tree. To me they look messy. The males do this during the summer after flowering, the females a year later after ripening their fruit. Both structures are quite hard and are best removed with loppers or a saw. Bracts surround the pedicel (?) that separate and slide off once cut from the tree.
As evergreens, palms are ready to grow year round when conditions allow. Temperatures are most amenable for Trachycarpus growth late spring into mid fall so the best growth is obtained with some summer irrigation. Drought stressing a palm, especially in its juvenile years will stunt it. A mature palm can show the effects of drought the remainder of its life in a narrowing of its trunk diameter that will never thicken or fill out later. This gives the trunk a corseted or hourglass look.
A few years ago I bought a selection of Trachycarpus fortunei from Plant Delights named ‘Raleigh’ (now known as Taylor’s Form) which did especially well during one of our particularly bad winters. This one seems to keep growing later into the fall and is the only one I’ve had, so far, to suffer significant winter damage here. Apparently, while still trying to grow, one of our erratic cold snaps did some damage to the crown and two of the emerging spears, held vertically, died and were easily pulled away from the plant. Fortunately no rot or cold then got into it to further damage the apical meristem. It turns out that this was just a little hiccup along the road.
This response is typical in palms that are pressed to their colder limit. If the meristem is killed, the tree is dead.
My largest T. fortunei was planted from a five gallon pot about sixteen years ago. Today the fronds reach out forming a canopy 12 feet in diameter, the top of the trunk has passed the 13′ gutters with its new fronds stretching its height another five feet up. It’s a beautiful and very healthy tree.
I grow several other Trachycarpus spp. including T. takil, T. wagnerianus, T. martianus and T. latisectus described in their captions. Unfortunately it is only T. fortunei that can be found in any size. T wagnerianus is becoming more available here with some size. You should always check the inventories of our local specialty growers before you look too far afield. I planted a T. latisectus out earlier in the middle 00’s and lost it, which taught me, again, not to be too hasty when planting these out. It was too small and was killed by what I would call a normal winter with its share of freezing temperatures without dipping too far down. I replaced the it the next summer and have since planted it out again early this last fall ’14. I also lost my Jubaea chilensis the same winter to impatience.
The rest of this post describes some of my other experiments, which I plan to continue. Their are other Trachys, Sabal, hybrids and maybe even another Butia worth trying. Peruse the growers on the internet, their info is often enlightening, if not a little too ‘rosy’, because there are new species and populations available now that haven’t been. Promise is out their lurking. And always take the comments of others with a grain of salt. Because a plant worked or failed for someone else does not mean you will obtain the same result. Ask questions. Be critical. Use your noggin!
I anyway am still trying to ‘tropicalize’ my back garden and always, always, always, keeping the naysayers, boobirds, negative nellys and dream killers at bay. We have a lot to do in this world!
Chamaerops humilis – This Mediterranean Fan Palm probably has a virus which gives it a very distinctive ‘tie-diyed’ effect to its fronds. I’ve never planted it out. I lost its parent plant 8 years or so ago messing around, dividing off ‘pups’ before I tried the mother plant in the ground, so I don’t want to screw it up and wait another 8. Sadly, this was the only pup with enough roots to survive. All of the other plants, mom included, died after the procedure…I’m not a propagator. These are slow. Got the original plant from Sean Hogan’s Cistus Nursery.