A Gardening Journal
The Best Season Ever: Pollarding the Poplar
- Published: December 22 2015
The silvery stems of the pollarded white poplar could hold their bright color all through the Winter. But the quirk of poplars is that they shouldn't be pruned while their sap is rising in late Winter or Spring. Worse, if this bizarrely mild Winter continues, who knows how early the sap-rise might begin.
Annual pollarding is necessary to create such a pleasingly-compact and rounded canopy so, if it can't occur in Winter or Spring, that means Fall. The "Winter" show of a pollarded poplar is so ephemeral, then, it should be ended before Winter even begins. Yesterday was the day: the last of Fall.
Pollarding densely-branched canopies is a bottom-up process, because the branches emerge too closely together to permit frontal assault, let alone attack from above. In the picture below, I've cozied the ladder to the trunk, but could at first stand only on the ladder's lowest steps and reach upward to remove the bottom stems. With those stray poke-my-eyes-out branches clipped off, I could stand on higher and higher steps. The pruning was more and more comfortable with my hands just chest-high, then waist-high.
Five minutes later, there were just a few more stems to go.
Done. The difference is shocking: A large and graceful head of white branches is now a stubby, club-like top foot of a slender trunk. Maintaining a pollard of white poplar isn't for wimps.
Until new stems begin emerging—which could be in three months or longer if the Winter is of normal severity—this branchless trunk will greet any garden visitor: The poplar is at the front of the bed along the driveway. The enormous old American holly is the perfect dark and evergreen backdrop to the poplar canopy, whether the poplar is in leaf or, as in the Fall, just "in stem." Alas, the holly is just as good at calling attention to the now-bare trunk.
On the plus side—or at least the ego-stroking side—this uncompromisingly prompt pollarding of Populus alba 'Richardii' also shows that this gardener isn't afraid of gardening for the long-term. If the goal is an astounding poplar pollard Spring through Fall, it's still a bargain even if one cost is an astoundingly bare trunk all Winter.
Now, if only I could find a use for the sheaf of fantastic white branches. If only there were a shockingly spare and fashion-forward hotel nearby that would welcome the occasional gigantic lobby arrangement.
Gathering all the cut stems together in such a dense array sure does show that the display of twigs is even better when they are closer together. More really is more. Could I help this poplar produce an annual canopy of first-year growth that is more dense than the one I cut off just minutes ago?
The tree itself will provide some of the help. Each year, its trunk, as well as the head of stubby chopped-off branches, will become just a bit thicker. Plus, more than one side stem will often emerge from the base of each stub: After all, pruning and pinching are the classic ways to remove the growth-inhibiting hormone produced by branch tips. Pollarding is nothing if not a hyper-intense pinch!
In 2016, I might not even need to limit my pinching to Fall. Yes, poplars should not be pruned at the height of their sap-run season: Spring or, in milder climates, from February on. But what about tip-pruning in mid-Summer? Does the very fact that the young shoots produced by pollarding are so fast-growing all season also mean that their sap is, in effect, always running?
If I could pinch back just the soft tips of new stems in mid-Summer, each stem would have time to produce more side stems by Fall. More stems in a more-dense canopy would mean an even more striking Fall display of bare branches. Or maybe such "soft tipping" of new stems will create ends that drip sap messily onto anything below.
Only one way to find out: We'll revisit this pollard in July or August of 2016. Stay tuned.
Here's another look at the silver-white stems this pollarded poplar displays in Fall.
Here's a look at the luminous Fall foliage of this particular form of white popular, the gold-leaved cultivar Populus alba 'Richardii'.
Here's how to grow Populus alba 'Richardii', as well as close-ups of its remarkable gold and white foliage while still "just" in its warm-weather hues.