A Gardening Journal

Camperdown Elm in Full Foliage

Three weeks ago, this enormous weeping elm was in "full samara," meaning that its spring display of countless pale-green winged seeds—known as samaras—was at its height. Their countless fluffy clusters gave the whole tree the look of a giant ruffly hoop skirt. And I mean giant: I parked my big boxy brown Jeep nearby for scale.

 

Ulmus glabra Camperdownii with my car 052917 640

 

Now that the foliage has emerged, the tree looks like a huge haystack or some sort of unstoppable green monster that will sneak up on my car and demolish it. The canopy's incremental but, over time, substantial upward creep has created a roomy space around the tree's trunk. Now that the large, profuse, and overlapping foliage is present, that space is a secret hideaway; mature Camperdown elms are irresistible to children too, not just adults.

 

Ulmus glabra Camperdownii trunk beneath the skirt 052917 640

 

Looking more closely, you can see that the faded samaras are still pretty much in place: they are the now-brown fuzzy bits that look like clumps of sawdust.

 

Ulmus glabra Camperdownii new foliage faded samaras 052917 640

 

As the samaras dry still further, they will fall from the branches. They won't be released as readily into the breezes as they would have been from the branches of an Ulmus glabra of normal upright habit. Its highest branches could be one hundred feet above ground. Samaras of this U. glabra 'Camperdownii' are likely to fall almost straight down, to become more or less contained by the canopy's thick, ground-sweeping curtains of foliage.

 

Ulmus glabra Camperdownii new foliage faded samaras 052917 cropped 640

 

This is likely a help in restricting the range over which the seeds germinate. I'm not aware that seeds of Camperdown elms germinate into more Camperdown elms; if this were the case, this extraordinary cultivar would simply be propagated from seed. Instead, it's propagated by grafting, which suggests that seeds that do germinate produce elms with the habit of the straight species: spreading but upright.

 

Between 1835 and 1840, the original Ulmus glabra 'Camperdownii' was discovered as a naturally-occuring mutant on the estate of Camperdown House, in Dundee, Scotland. Since then, all Camperdown elms have been propagated from that tree and its countless propagated-by-grafting descendents. It's striking that, whatever the mutation was that produced a tree with such a radically weeping habit in a species whose normal habit is so strongly upright, the mutation doesn't carry successfully into the tree's seeds.

 

Also striking is that, although untold thousands of Camperdown progeny have been growing generation after generation, producing billions upon billions of new Camperdown cells, Camperdown elms don't produce stems that revert to the upright habit of the straight species. However it happened, that original Camperdown mutation is remarkably enduring and, even, irrevocable; there's no Reverse or Undo function on this tree's keyboard. And yet, that mutation—which is genetic (if it weren't, growth produced by those countless vegetatively-produced cells wouldn't weep) is not passed down reproductively as the trees' flowers' chromosomes divide and reconfigure during formation of seeds.

 

Just as wonderfully weird is that other no other Scots elms with similarly weeping habit have (so far!) been discovered. It's been nearly two centuries since that single mutation at Camperdown House and, yet, its descendents are still the sole available weeping cultivar of this species.

 

There is, however, another cultivar that, while not weeping, is also not upright: the so-called tabletop elm, Ulmus glabra 'Horizontalis'. Its branches don't weep, but neither do they grow upward with any eagerness. Instead, growth is sideways and outward, forming a non-weeping tree with a wide but flat canopy. There's a majestic weeping Scots elm at an estate in Ontario that is now this Relais & Chateaux hotel; when I visit this Summer, I'll confirm which cultivar it is.

 

It's unknown just how large the Camperdown mutation is but, regardless, there's no correlation between the extent of the change in the chemistry of a chromosome—the mutation—and the affect of that mutation. (Change just one letter of one word in a sentence, and the meaning of the entire sentence could become quite different or even destroyed outright). Because the weeping mutation isn't passed down reproductively, we can hypothesize two realities: the first is that seeds that receive the mutation aren't viable while seeds that receive the unmutated genes are. In this case, samaras from this Camperdown will germinate into seedlings beneath its canopy that will all mature into trees that lack the weeping habit.

 

The second possibility is that the mutation—which, remember, has radically interfered with the tree's normal vegetative ability—has also interfered radically with its reproductive ability. In this case, there will be no seedlings beneath this Camperdown's canopy. (Elm trees are self-fertile, which means that even a single tree can produce viable seed. So it doesn't matter that there isn't a second Campdown nearby.)

 

Stay tuned.

 

 

Here's how frilly and flouncy Camperdown elm looks after its reddish flowers have matured to clusters of papery greenish-yellow seeds known as samaras.

 

Here's how to grow golden-leaved Scots elm. Its hardiness and culture are the same as for the Camperdown cultivar.

 

Here's another species of elm that has spontaneously produced a strongly-weeping form.

 

 
 
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