A Gardening Journal
Today in the Garden of a Lifetime: Directional Fall Foliage of the Portal of Persian Ironwood
- Published: October 28 2015
Persian ironwood is renowned for its Fall foliage, which can last for well over a month and transition through rust, orange, and red to yellow and pink. The dark and muted colors here are the early ones in the show; after a few more frosts, the leaves will take on a stronger yellow echoing the developing spirals of 'Yellow Ribbon' arborvitae.
Only this week did I realize that ironwood's Fall foliage doesn't progress at the same rate on all sides of the tree. And, because I keep my pair of ironwoods tightly trimmed as the side pillars and crossbeam of a portal through a Belgian fence of espaliered beeches, each pillar's front side is just a foot or so from its back. And, my oh my, are the colors different!
Below, the green foliage on the other side of the pillars is still barely touched by the Fall foliage fever.
Below, the entire portal, showing these all-green sides and the pink-foliaged top stems. I pruned the pillars severely in mid-Summer, but left the top stems to grow so they can extend all the more, to bear the maximum amount of—as is their quirky want—pink foliage. I'll prune them off in mid-Winter, so they can once again have a full season, Spring into Fall, to lengthen before their foliage turns pink again.
In the picture below, the colors of the now-colorful sides of the pillars are nearly of a piece with the stems of pink foliage that are projecting wildly from the crossbeam.
Seen from the side, the full range of colors that occurs around the tight circumference of the pillars is dramatic. The pillars are perhaps two feet thick and, so, are only about six feet around. And yet the foliage just a foot farther to the left is clearly rust and pink; that of a foot farther to the right is quite green.
The difference is the sun. The colorful side of the portal faces south, and the green side north. With clipping, the growth of the pillars has become dense enough—and (I guess) the pillars just wide enough—that the south side provides shade for the north. And so, somehow, the shaded north foliage isn't as quick out of the gate for Fall colors.
But what of the all-pink foliage of the stems springing out from the crossbeam?
This growth is strikingly more open than that of the clipped pillars below it, so none of it provides any sustained shade for any of the rest. Instead, all the foliage receives all possible sun—and, so, all of those leaves have "gone wild" more completely than any others on the portal: all the way to pink, the scarcest color in Fall foliage
Here's how to grow Persian ironwood—Parrotia persica—plus pictures of how dignified the tree is in its mid-green Summer foliage. The cultivar I've used in forming this portal is 'Vanessa'.
Here are close-ups of the pink foliage of stems at the top of portal.
Here are more pictures of the portal overall, showing how colorful it is all Fall.