Louis Raymond experiments in his own gardens like

a mad scientist, searching out plants that most people have

never seen before & figuring out how to make them perform.- The Boston Globe

…Louis Raymond ensures that trees can grow in Brooklyn…

or just about any other place where concrete consumes

the dirt and skyscrapers shield the sunshine.- USA Today

 
 

NEW Trips to Take!

Myrtle's easy when the conditions are right.

 
 
 
 

NEW Plants to Try!

Louis tries to capture the exact words to describe the fleeting but deep pleasures to be found in these Summer-into-Autumn incredibles.

 
 
 
 

New Gardening to Do!

Allergic to bees? You can still have an exciting garden, full of flowers and color and wildlife.

 
 
 
 

Plant Profiles

Gold-leaved English Oak

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Could this foliage be more exuberant?  Gold-leaved English oak is one of the joys of the Spring garden.  The dangling flower clusters provide textural interest, but it's the leaves that provide the color.  Acid-yellow, lime-green—whatever you call it, the hue almost calls for sunglasses.

 

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The color tones down considerably during the Summer.  See "How to handle it" for ideas to enhance the show.

 

 

Here's how to grow this gloriously vivid oak:

Latin Name

Quercus robur 'Concordia'

Common Name

Gold-leaved English Oak

Family

Fagaceae, the beech family.

What kind of plant is it?

Deciduous tree.

Hardiness

Zones 4 - 8

Habit

Single-trunked.  Open and upright.  Eventually a medium-sized tree. 

Rate of Growth

Slow.

Size in ten years

Variable; my young pair seem likely to become ten to fifteen feet tall, six to ten feet wide.  'Concordia' always stays smaller than the straight species, which can grow to a hundred feet tall and wide, larger than any beech.  'Concordia' doesn't grow more than forty-five feet tall and wide.

Texture

Thanks to the lobes of the leaves, lighter and frillier than otherwise.  Open, with intervals of exposed branches amid areas of dense foliage. 

Grown for

its foliage, which emerges solid butter yellow in Spring.  It fades to green in the Summer.  Is the color the result of age of the foliage?  If so,  well-timed pruning could force another flush of butter-yellow growth.  Or is the color stable only when temperatures are, comparatively, cooler, and there's a wider spread between mid-night and mid-day temperatures?  If that were the case, then foliage of any age will fade to green in the Summer, when days as well as nights are hot.  See "How to handle it" below for strategies that may enhance the display.

Flowering season

Mid-Spring, as the new leaves emerge.  Pendulous clusters of apetalous gold-brown flowers, charming at close range, mature to typical acorns.

Color combinations

'Concordia' foliage is uncompromisingly butter-yellow, and its best siting is amid foliage that's darker—either green or purple—or dramatically lighter due to strong variegation with cream or white.  A plant that could supply almost any shade of blue, from sky-blue to indigo, and almost certainly from flowers, not foliage, would be the welcome third color to the display.  I'm hard-pressed to imagine 'Concordia' in association with pink, orange, or red.

Plant partners

Oaks typically have deep roots and, so, are unusually hospitable to underplanting.  They also have a relatively open and, often, high canopy.  No surprise, then, that they are a favorite tree for shade-gardening, welcoming tough and stalwart shrubby evergreens as well as delicate Spring ephemerals to the dappled-shade ground under their canopy.  So you have an unparalleled range of plants to consider that you can expect will grow in happy as well as intimate partnership with 'Concordia'. 

 

Because 'Concordia' is recommended for morning sun only, partner plants need to be comfortable with that exposure.  Plants at the base of the tree are shaded by its canopy as well as by whatever is shading the tree itself from western sun, so they had best be very shade-tolerant.

 

The trunk and limbs are dignified but not exciting without their leaves in the cold months, so why not use them as scaffolding for ivy or climbing euonymus?  Both are extremely shade-tolerant.  Although, the deep green leaves of plain-Jane ivy, such as Hedera helix 'Baltic', would be terrific contrast, I'm encouraging H. helix 'Manda's Crested' at the base to ascend up the trunk as far as it can.  The leaves of this cultivar have pointier lobes, as well as a distinctive cupped profile.  If the ivy is very happy, it will form adult growth when it's as high as the 'Concordia' canopy, turning this deciduous tree evergreen from top to bottom.

 

Almost any azalea, rhododendron, or cherry laurel could provide welcome broadleaved-evergreen bulk around the trunk of 'Concordia'.  Because I'm growing ivy up the trunk, I've chosen a shade-tolerant conifer instead, the midget-leaved yew, Taxus baccata 'Adpressa Fowle'. 

 

Oak branches are strong, so the trees can easily host hanging plants that crave the partial sun that would typify a Summer amid the 'Concordia' canopy.  Who needs a lathe house for orchids or ferns if there's a low-limbed oak handy?

 

If you've sited your 'Concordia' where larger trees to its west will provide the afternoon shade 'Concordia' is supposed to prefer, those trees can be a partner in style, not just in shade.  If you're planting both at the same time, be sure the tree providing the West shade grows faster than the 'Concordia'.  Purple-leaved Norway maple, Acer platanoides 'Crimson King' is fast-growing and its foliage is as dark purple as the oak's is bright yellow.  Metasequoia glyptostroboides is infamously fast-growing—three feet a year isn't unusual—and its feathery light-green foliage would cast a light shade.  If your soil is good and your soil moisture steady through the Summer, that would be shade enough.  What about planting 'Concordia' in a ring of Metasequoia, creating the message that this gold tree has mythic import, and warrants protection from all sides?  Metasequoia trees are broad at the base as well as tall at the tip.  Plant them in a ring seventy-five feet across lest their lower limbs grow right over the top of the 'Concordia'.       

Where to use it in your garden

'Concordia' needs thoughtful siting.  The tree is almost incandescent when its foliage is bright in the Spring—but by August the color may well have calmed to a boring green.  Most sources advise providing afternoon shade, too.  

 

It might be difficult to find a spot that's visually as well as "shadily" appropriate, especially for a tree that could grow over thirty feet tall.     

I don't have room for many full-sized trees in my garden, especially any that could become the size of 'Concordia'.  I also have few locations that provide afternoon shade—and fewer still where the shade could protect a tree large enough to quality as a shade tree itself.  Instead, I've planted a pair of 'Concordia' to flank the main doors into the carriage house.  The structure faces East, so by about 1 PM the trees are protected from western sun.  And their striking foliage is displayed to advantage against the white clapboards, too.  I'm pollarding the trees to keep them compact enough to remain in the carriage house's protective shade, as well as to give them an unusual form.

Culture

Quercus robur is tolerant, indeed.  As long as the tree isn't stressed by drought or overly-strong sun, it will thrive in almost any soil, alkaline or acid, clay or loam or even sandy.  It's a welcome exception to the rule that excellent drainage in Winter is the key to maximal hardiness and vigor.  That said, good drainage is always wise, and Quercus robur isn't a tree for sites with clearly bad drainage, let alone bogs, in which cases you might consider Alnus,Chamaecyparis thyoides, Leitneria, Salix, or Taxodium instead.  Growth is best in soils that are nutrient-rich, and that supply enough water year-round; clay soils usually succeed on both counts.

How to handle it: The Basics

Plant container-grown individuals in Spring or Fall.  If this oak behaves like its great colleague in the Fagaceae family, the beeches, trees that are transplanted (and which, at the nursery, will be balled-and-burlapped) are best dug as well as replanted in the Spring.

 

'Concordia' is usually described as needing afternoon shade, lest the foliage scorch.  The large specimens thriving in full sun in so many of the pictures of 'Concordia'—even as solo focal points in large meadows, without a shred of shelter—didn't get the message.  It's probably the case that full sun per se isn't the challenge, it's full sun combined with drought stress.  If soil moisture is sufficient throughout the growing season, the tree can handle full sun.  Soil that is deep, not shallow, helps to the same end.  The roots of oaks, typically, are more tolerant of the lower level of oxygen that would be inevitable the deeper the roots penetrate into the soil—and those deeper reaches are where moisture will still be present even when shallower layers are dry.  

 

My garden—fairly flat, with deep soil and a high water table—would probably be any oak's idea of heaven.

How to handle it: Another option—or two!

Oaks typically don't produce long enough shoots in response to pollarding to be grown as "single-point" pollards, where all stems are pruned back to a central knob at the top of the trunk.  Instead, the top of the tree is pinched when it's tall enough to encourage more side branches, and those side branches are, themselves, pinched when they become a couple of feet long.  After a few seasons, the result is a relatively compact canopy that, after pruning, might be four or five feet across, and in full new growth probably not more than seven or eight feet across.

 

Pollarding can be done any time the leaves are off the tree in Fall, Winter, and early Spring.  Pruning in Fall ensures that a cleanly-shaped canopy is maintained all Winter long.  

 

After my pollards are old enough to have well-formed heads, I'll experiment with an additional trim in mid-Summer, when the foliage has begun to tone down from acid-yellow to green.  The hope is that a second crop of new foliage will be produced, to reprise the bright show of Spring.  In four or five years, I should be able to put the trees to the test.  UPDATE of 091015: An early-August pruning has, indeed, encouraged a new flush of gold foliage. See that article for more details.

 

Although I haven't tried it, I don't see why you couldn't espalier your 'Concordia'.  Oak wood is a classic "hard" wood, used for carpentry of all kinds, especially furniture and flooring.  Because the wood is so strong, and has the ability to span long distances as limbs, the trees are naturally wide-spreading.  An oak that has been trained on a free-standing frame could, after many years, be released from its frame (but not the yearly pruning to keep it to its two-dimensional espalier form), to create an espaliered tree that is, itself, free-standing.

 

Somewhere, some century, would some one please create a line of mighty 'Concordia' espaliers, backed by parallel line of mighty yew hedging?  And then, thirty years into the oaks' training, release them from their supporting frames?  The display would be visually stunning, and conceptually (let alone structurally) staggering.

 

Quirks or special cases

Quercus robur has been planted for centuries; there are individual trees that have been actively tended for centuries, too.  Oaks that are pollarded or coppiced are believed to live longer than those growing free-range.  Some of these regularly-pruned individuals are over a thousand years old; it's rare for a free-range Quercus robur to live more than five or six hundred years.  Even at that, these are very long-lived trees, and it's not surprising that, after growing in association with humans for many generations, numerous cultivars have been identified.  See "Variants" below.

Downsides

Supposed sensitivity to scorch, caused by strong sun coupled with insufficient moisture, limits flexibility in siting to locations that can provide some afternoon shade, reliable moisture, or both.

 

Oaks are susceptible to sudden oak death.  The disease does not seem a threat east of the Rockies.  Contact the local office of the USDA Cooperative Extension Service for guidance where you're gardening.   

Variants

Quercus robur cultivars can have habits that are columnar, to varying degrees of density and narrowness; weeping; or globose.  In addition to the bright yellow of 'Concordia', leaf color can be purplish (but nothing as definitive or enduring as the purple of the best forms of purple beech), bluish, deeper green, or dotted or splashed with cream.  Leaf lobes can be narrow and elongated, or absent entirely; the leaves of 'Cristata' are crinkly and congested. 

 

Many forms tout improved resistance to pests and diseases, mildew in particular.  In my experience, 'Concordia' is not noticeably mildew-prone.

 

On my wishlist are one of the narrowest of the columnars, 'Kindred Spirit', and one of the variegated-leaf forms, few of which are ever seen in commerce.

Availability

On-line and, sometimes, at "destination" specialist retailers.

Propagation

Grafting.

Native habitat

Quercus robur is native from the British Isles to north Africa and western Asia.  'Concordia' was first raised in Belgium in the 19th Century.






 

 

 

 

 

 

 

 

 
 
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