Daily Archives: July 17, 2012

Just north of Dallas, on the mutual border between the suburbs of Richardson and Plano, lies an anomaly. It lies on the north side of a city park, along a recently refinished and refurbished bike and walking trail, surrounded by trees, shrubs, and a tremendous amount of poison ivy. It’s easily accessible, and can even be seen from the air. Take the DART Red Line train north toward Plano, and look west in between the Galatyn Park and George Bush Tollway train stations. Even in the height of summer, it’s hard to miss, but it’s particularly visible after Halloween, once the leaves start dropping from the trees.

Contrary to its appearance, this isn’t some lost tomb from an otherwise unknown Mayan city. It isn’t an Olmec temple or sacrificial site. It wasn’t left behind by some unknown extraterrestrial race, just waiting for us to learn its secrets and activate it. A few astute individuals may recognize it as a train trestle: the current DART line runs along the land previously used for a freight line heading north to McKinney, and this was almost all that remained after the bridge over a rather wide local creek was demolished.

All on its own, this trestle is just crawling with what my friend Dave Hutchinson likes to call “a sensawunda”. Anybody with even a slight bit of imagination can come up with all sorts of stories to explain its presence, and it inspires enough to brave ticks, chiggers, and poison ivy to stomp through the vegetation and leave a trail. That’s not the main focus of this discussion. Believe it or not, this little artifact can pass on a lot of information to anyone working either on miniature gardens or dioramas.

If you go back to the photo at the beginning of this post, don’t look at the pylon. Look at the trees around it. Note in particular how the trees are rotten with vines of all sorts, including one huge vine that’s actually bending down the top of the oak tree on which it resides. You don’t see any vines on the pylon, do you? In fact, the whole thing is surprisingly vegetation-free, save for a small sapling at the top. No lichen, no moss, no ferns…it’s botanically bereft, all things considered.

When it comes to our understandable human fascination with ruins and monoliths, half of the appeal seems to come from these ruins covered with various flora. (As to why ancient ruins and dinosaurs seem to go together for ten-year-olds like French fries and catsup, well, that’s something best discussed by psychologists, not botanists.) The ruins of Angkor or Tikal not only awe today, but they inspire repeated fictional variations. It’s to the point where imagery of stone ruins seemingly require them to be covered with vines and creepers, obscuring all but the basic building shape.

The problem here, and an issue that needs to be considered with any miniature recreation of, say, Temple II, is that you need to consider the general conditions of the miniature area you’re trying to create. By way of example, the White Mountains National Park in New Hampshire, USA is full of gigantic granite boulders, many the size of small houses, broken free from the surrounding rock and rounded by rolling down the mountainside. Some are so large, the tops have collected enough humus from fallen leaves that small maples and oaks grow atop them. Some of those trees have managed, over the years, to reach their roots down to the ground, producing beautiful natural nebari.

What makes this work, though, is a relative impermeability of the rock, and that’s something that’s very hard to duplicate in miniature. With a house-sized boulder, the granite has enough pits to hold more water than it would if the surface were polished, and the decayed leaves on top act as a sponge. In miniature, there’s no way to create that effectively, short of setting a water drip atop a comparable rock to replace what is lost from evaporation.

With concrete, the situation is aggravated because concrete is very good at wicking away moisture. I’ve warned people for years, after my own horrible experiences, that the standard concrete planters used by cities to grow trees and shrubs don’t work well in Dallas, because any excess water in the container gets drawn into the concrete before it evaporates away. In the short term, this works well for keeping tree roots cool in Dallas temperatures, but without a regular and steady water source? It’s great for cactus, but death for most other plants in a typical Dallas summer.

In the photo above, that’s precisely what’s happening with that little tree. The pylon apparently has a space up top that collects dead leaves and the occasional rain, but it’s also baked in the summer sun. In a few years, it might make a decent yamadori, but it’s never going to grow into a full-sized tree. When the loam up top dries out, it gets blown around by the prevailing winds. When the rains return, any trace minerals wash out. Were we to get a lot more rainfall than we do, that top might make a decent location for small carnivorous plants such as sundews or butterworts. As it is, if I wanted to plant something, prickly pear cactus would be one of the few sane options.

Not that I plan to do this with the Richardson Pylon. Although the surface temperatures deter vine growth just due to new growth wilting or even cooking off in summer, the east side makes good shelter for other inhabitants. For instance, the surrounding woods are full of caterpillars, which make good food for the young of this nest of paper wasps.

Now back to the wonders of concrete. As mentioned before, abandoned concrete around here tends to remain vine-free, except occasionally on the east side of installations. This is because of both concrete’s exceptional ability to retain heat and its ability to draw off moisture. Vines with aerial roots or suckers, such as poison ivy or English ivy, can’t get enough of a grip during summer to make much of a difference. North Texas is rotten with raspberry brambles, but the singular ability of raspberry runners to climb by hooking obstacles doesn’t work when the surface is relatively smooth. About the only place where vines can get established is when the slab itself cracks enough to allow a serious purchase.

For example, this is the trestle on the other side of the creek valley. The whole cliff is covered with vines and trees, but the only place where the vines are making inroads in the concrete? It’s only in the spaces where the slab has buckled to the point where the roots can sink in. In another twenty years or so, those vines may crack things enough to allow hanging trees, but nothing is getting through the main slab for a while.

And with that, here’s hoping that this wayward pylon gives some gardening design inspiration. Elvis help me if I ever had the opportunity to design a garden that had a feature like this, because I have Ideas.