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

Umbrella Arborvitae

Most plants welcome routine attention, such as a bit of weeding, thinning, or deadheading, or clipping off a dead twig. Combined with my interest in the outer limits of training—espaliers, hedges, pollards, topiary, seasonal cut-backs and even occasional massacres—it's the rare plant in my garden that is left in peace for even a month, let alone the season or the decade.

 

Here's one:

 

Thuja occidentalis Umbraculifera overall 040516 640

 

This is a dwarf form of eastern arborvitae, Thuja occidentalis 'Umbraculifera'. After almost a decade, it is just beginning to show why it was given its cultivar name, which translates as bearing an umbrella or, at least, having the mounding-up-to-the-center shape of an umbrella. After another decade or two of being left alone, the likeness will be even better. Then it could be a broad cone two feet high and four to five wide, with just the perimeter curving steeply down to the ground.

 

Thuja occidentalis Umbraculifera cropped 040516 640

 

See above and below, how the foliage is not arrayed in flat fans, as is the case with more mainstream arborvitae cultivars such as 'Nigra' or 'Rheingold'? Like many conifers in the Cupressaceae family, arborvitae can produce foliage of two different types, adult and juvenile. Typical adult foliage is soft, and forms flat fan-like sprays of flat scale-like leaves—or, as here, dense thread-like masses of those same flat scale-like leaves. 

 

Thuja occidentalis Umbraculifera interior fingers 040516 640

 

It's the shape of the scale-like leaves that determines if the foliage is adult or not. Leaves of juvenile foliage are pointy, and look more like that of junipers. See the difference on the fifth picture of this PDF. 

 

Growing juvenile foliage when young and adult foliage when mature would be too simple. Thuja occidentalis 'Linesville' seems to stick with juvenile foliage regardless of how old it gets, whereas 'Umbraculifera' produces adult foliage even as a youngster. Such quirky differences among cultivars are usually a result of propagation, which is by cuttings.

 

Cutting-grown descendants tend to remain in the same phase of foliage as the cuttings from which they were grown. Arborvitae propagated as rooted cuttings of juvenile foliage, then, usually continue to grow more juvenile foliage no matter how old and large they get. Cuttings of adult foliage continue to grow adult foliage even though, as little freshly-propagated plants, they seem like youngsters again. This tendency to stick with the form of foliage being produced at the time of cutting propagation seems to intensify generation after generation: A given juvenile form might sometimes begin producing adult foliage when old enough, but this happens less and less in its successive cutting-grown generations.

 

This confusion of age and, so to speak, dress is typical of some members of the Cupressaceae. Some forms wear juvenile clothing their entire lives, others wear adult clothing right from the beginning. Only individuals that are grown from seed usually follow a more traditional pattern of juvenile dress in youth and adult dress in maturity. As various perpetually juvenile cultivars of Chamaecyparis were introduced from Japan to Western horticulture in the 19th Century, they were grouped in a separate genus, Retinospora, until it was understood that they were just juvenile forms of Chamaecyparis.

 

Thuja occidentalis 'Umbraculifera', then, is a dwarf but adult-foliaged form. Over many years, it will change only in size, not habit or look. As long as I ensure that it isn't shaded by adjacent plants, it needs nothing from me but time.

 

 

Here's how to grow a colorful upright cultivar of eastern arborvitae, Thuja occidentalis 'Yellow Ribbon'. Its hardiness and cultural requirements are the same. It, too, can be left alone for decades to elaborate its natural shape, that of a fat cigar. Unlike 'Umbraculifera', it can also be trained with radical intensity. Pruning its pillar-like canopy of foliage into a spiral would be too easy: I'm training the tree's trunk into a spiral; the foliage merely follows along.

 
 
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