Today in the Garden of a Lifetime: 'Concordia' Oak's Second Flush of Gold Foliage

The foliage of 'Concordia' oak fairly glows from Spring to early Summer.  And my young tree also responded to a quick trim-back in late Winter by sending out new shoots that were three and four feet long by August.  So much fresh energy and promise!


But by then, the Spring's gold foliage had turned green, and those new extensions were looking wild and ugy: Their foliage had developed a nasty case of mildew, as well as some scorching. 


Quercus robur Concordia Spring growth that is scorched and mildewed 091115 640


So I gave this Quercus robur 'Concordia' a "pity prune."  I cut off the yucky stuff so that the plant could wait out the rest of the growing reason in dignity if not style.  The tree, though, had another idea: a second flush of glowing gold foliage that was also mildew-free.


Quercus robur Concordia new stems from the side 091115 640


Even when photographed on a rainy cool morning, the foliage of this second flush of growth is as luminous as that of the first


Quercus robur Concordia closer 091115 640


These colorful shoots have emerged over much of the young tree's canopy. 


Quercus robur Concordia Spring canopy overall 091115 640


I'm pruning my 'Concordia' so that its branches form a rounded, dense, and comparatively low-to-the-ground head of foliage: An oak standard, in other words.  While vigorous new stems seem to form quickly—this tree was pruned just over a month ago, remember—they aren't yet emerging uniformly.  There are many at the top, but only a few at the bottom.  Plus, they have quickly become so long that, combined with their patchy pattern of emergence, the look is more punk than pretty.


Next season, I'll pinch tips of these high-Summer stems when they are only inches long, which should reduce the length they could achieve before frost while also stimulating emergence of side branches.  The result will be more but shorter stems of colorful foliage—and, conveniently, an ever-denser and rounder shape for the canopy of this oak standard.


But what if most of the stems of this second flush of growth still emerge from the top of the standard, not all over?  If there are enough of them, and they've been pinched to keep them dense, not wild and stalky, so much the better.  In Spring, when all the foliage of this deciduous tree is new, the entire canopy is gold.  In late Summer, if just the new upper foliage is gold, the look will be as if the canopy were only dipped in gold, not dunked in it.


Here's how to grow Quercus robur 'Concordia'—and a look at how exciting the glowing golden foliage is in May.

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