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

Lemon Bush

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Here's the eucalyptus that is so lemony, actual lemons seem like weak tea.  With only the slightest touch, the leaves infuse the air even more pungently than those of lemon verbena.  (What it is with wannabe citrus?  They out-citrus citrus.)

 

The fragrant oil of lemon bush isn't just powerful enough to use in perfumes.  Ever light a citronella candle?  That's lemon-bush oil you're burning.  This is the eucalyptus with fragrance so sharp that mosquitoes detour around it.

 

I bought lemon bush just for the fragrance, but I'll also grow it for the pink fuzzy stems and the long leaves that catch every rain drop they can.

 

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And because lemon bush loves to be pruned, pinched, and trained.  No surprise that the gawky first-year seedling in these pictures can become a dense bush: The common name isn't lemon sapling, lemon string-bean, or gangly lemon thing.  It's lemon bush, and a bushy one at that.

 

Better than a bush, though, is a bush-on-a-stick, a bush-with-a-trunk: a standard.  Yup, I've got the bug bad for anything that's sort-of-citrus, as well as for anything that can be trained into a standard.  A lemon-bush standard would be in great company; Here's another one in my collection. 

 

With a trunk that's, oh, three feet tall, the "bush" of lemon bush will be right at nose level.  Delicious!

 

 

Here's how to grow the ultimate in lemon-scented plants:

 

Latin Name

Corymbia citriodora, also Eucalyptus citriodora

Common Name

Lemon Bush, Lemon Eucalyptus

Family

Myrtaceae, the Myrtle family.

What kind of plant is it?

Broad-leaved evergreen tree.

Hardiness

Zones 9 - 11

Habit

Vertical at all times unless pruned, usually with a narrow canopy as well.

Rate of Growth

Fast.

Size in ten years

Growing free-range in ideal circumstances, Corymbia can put on six feet a year.  A tree a decade old, then, could potentially be the height of an East Coast shade tree, which would have, more likely than not, needed several decades to reach that height instead of just one.

 

Grown from seed as an annual, Corymbia can soar to five or six feet by September.

Texture

Extremely gawky and even scrawny as a fast-growing youngster, thickening with age.  Tall as an adult, showing many yards of notably vertical, straight, and white-barked trunk, with clusters of foliaged branches at the ends of high and otherwise bare limbs.  Distinctive and open. 

Grown for

its foliage:  As a youngster the plant has only juvenile foliage: bluish and narrow, quite sandpapery to the touch, up to six inches long, and reeking—truly, the word isn't too strong—of lemon.  Adult foliage, similar in size and shape but smooth, has a lemony reek as well, but by then the tree is often so tall that the foliage is high above reach. 

 

Conceivably, the juvenile foliage's texture as well as its remarkably strong smell deter browsing when the plant is young enough to be accessible to anything at ground-level with teeth, a yen for chewing, and a curiosity about the plant that's more lemony than lemons but, oddly, isn't actually a lemon at all.  Adult foliage is high out of reach of ground-level browsers, so wouldn't need to be sandpapery to deter them.  In their native Australia, eucalyptus are the sole food of an arboreal browser, the koala, but lemon bush is not a species they favor.  You can be too lemony even for eucalyptus monomaniacs. 

 

its bark: As an adult, trees have a very showy white or even slightly-pink bark.

 

its habit: Unlike, say, Eucalyptus cinerea, which can insist on growing at a serious lean, Corymbia citriodora is reliably vertical.  Combine that with its white trunk and height (to 100 feet; tall for generic trees but not for a eucalyptus), and you've got a great candidate for street trees and allees. 

 

its enthusiasm.  Lemon bush is so easy to germinate, and so fast growing as a seedling, that it's very successful as an annual.

Flowering season

Winter to early Spring.  The white flowers aren't very showy

Culture

Like nearly all the eucalypts:  Full sun, heat, mild Winters, lean and nutrient-poor soil, and excellent drainage.

How to handle it

As an annual from seed sown in Spring:  Spread the seed atop a soilless mix like sand and peat; light helps the seeds germinate, usually within a month.  Pot up the seedlings (carefully; they resent root disturbance) in a well-draining potting soil.  They grow fast, and because eucalypts resent root disturbance, it's best to plant in tall and narrow pots and, even so, pot up regularly.  Just slide the plant out of the current pot, set it at the right height in the larger pot, and gently fill around it with soil.

 

Pinch the branch tips regularly so your lemon "bush" actually grows like a bush; unpinched youngsters are—as in my picture—gawky little saplings.

 

As a bush for just the season or for the long term:  Any amount of pinching or pruning is fine, including cutting the entire plant down to four-inch stumps each Spring.  Eucalypts all respond quickly to radical pruning, and with almost defiantly fast-growing new stems.  Even more notable, the resultant growth sports juvenile foliage, not adult. 

 

Unlike, say, E. cinerea, though, where the juvenile foliage is circular but the adult foliage lanceolate, Corymbia citriodora foliage isn't dramatically different juvenile to adult.  But its eager rebound from serious pruning suggests that lemon bush could, indeed, be grown as bush indefinitely (by cutting it down to stumps each Spring; such to-the-ground pruning is called "coppicing").  But it could just as well be grown as a standard (by "pollarding": pruning all the branches back to the same point each Spring or, with even more discipline, back to little stubs at the top of the trunk), or even as a hedge (pruning several times a year, taking a lot of the top and almost as much off the sides).

 

Lemon bush: the privet of the outback.  Who knew?

 

Imagine the olfactory overload of a hedge of lemon bush right along a walkway, where brushing by the length of it was unavoidable.  Would this be too delicious, or is there a limit to how much lemon we can tolerate?  Does too much lemon scent, for too long, give you a headache?  Or would olfactory fatigue set in, and how quickly?  If the hedge is, say, a hundred feet long, do we smell the lemons for the first fifty feet but by the end of the next fifty don't smell them at all?  Or would we be good for a full hundred yards?

 

We fully hardy, you could plant lemon "bush" with the intent of letting it grow into a tree.  Eucalypts don't tolerate being dug, and barely tolerate being planted from a container.  But they grow so fast—six feet a year isn't unusual—that there's no point in trying to plant big ones, anyway.  Plant only youngsters.  A foot or two is tall enough, so the small plants are in little danger of being pot-bound.  But even if they are, don't attempt to tease out the roots when planting.  And don't improve the native soil either:  Eucalypts are very intolerant of rich soil, and soil with lots of phosphorus in particular.  This means that fertilizing is not only counterproductive, it could actually be fatal.

 

Water well at planting, but let the young plant's soil get somewhat dry between waterings.  After the plant has launched into its typical rapid growth—which could be only a matter of weeks—it's self-reliantly drought-tolerant.  Oddly enough, lemon bush also tolerates regular watering, and so can be grown as a lawn tree, where the grass all around it could, potentially, get watered several times a week or even daily.  Lawn fertilizers can have little or no phosphorus in them.

 

To overwinter in a container, provide all possible sun and a minimum temperature of fifty degrees.  Water only when the soil feels dry.  Pinch as needed to encourage bushiness.  Prune as needed in Spring to control overall size.  Or if greater size is desired, repot in Spring.  Do not disturb the roots in the process, though:  As before, just slide the young plant out of the current pot, set it at the right height in the larger pot, and fill around it with soil.

Downsides

Corymbia citriodora can self-seed rampantly, and if grown as a tree (that gets to 100 feet tall, remember), there's no practical way to disbud the flowers or prophylactically harvest the seed.  If self-seeding is a problem where you garden, keep your lemon bush pruned by one of the strategies—coppice, pollard, or hedge—in "How To Handle It" above.  Pruned individuals produce little if any adult growth, let alone the flowers and seeds that accompany it. 

 

Plus you'll have the distinction of keeping a well-pruned plant when nearly all of the other lemon bushes in the neighborhood will just be free-range.  To my mind, there's never any particular achievement for the gardener, let alone an actual victory, in growing a free-range plant.  Yes, the plant's alive, so there's possibly a milestone there, but it's still just growing on its own, marching to its own drummer. 

 

Plants that are pruned with dedication as well as insight, though, are in a duet with the gardener, a real partnership.  Gardener and "gardened" are, indeed, collaborating for life.  And not just over the lifespan (plant and gardener both) of a life, as impressive a duration as that could be.  But the liveliness of the life along the way, as well.  That's an achievement.

Variants

Few eucalyptus are hardy below Zone 8, let alone Zone 7.  Corymbia citriodora, no exception, is Zone 9 at the roughest.  It's also one of the few I can think of that you might want to grow for the long-term as a container specimen: The fantasy of an old standard, faithfully pruned and dutifully cycled out to the garden in May and back into the greenhouse in October is seductive.  Well, at least to me.

 

Gardeners who need to dive deeply into eucalyptus, though, need to live where the eucalypts do: In fairly dry and mild-climate locales like California, Arizona, around the Mediterranean, and, of course, where eucalypts are native, Australia.  There are hundreds of species, many of which are all too happy to hybridize all by themselves, too.  Send us updates on your many favorites!  And let me know where the world's longest lemon bush hedge is, so we can test out the literally linear relationship—the geometry!—of lemon scent and olfactory fatigue.

Availability

On-line and at nurseries.

Propagation

By seed in the Spring.  

Native habitat

Corymbia citriodora is native to eastern Australia.  

 
 
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