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Eugene Weekly : Gardening : 12.15.11

Evergreen, Evergold

Picking conifers for potted Christmas trees

Dwarf scots pines at Bloomers Nursery

Evergreens always catch my eye this time of year. In a few weeks I’ll be ready to appreciate the subtle beauty of leafless branches and interesting bark. But as the last leaves fall from deciduous trees and clog the roads and gutters the landscape looks suddenly bereft, and it is evergreen plants, both coniferous and broad-leafed types, that get my attention.

Among the broad-leafs, rhododendrons, pieris and camellias will always be popular because they have showy flowers as well as evergreen leaves. Laurels, both English and Portugal, are great hedge material and form a significant part of the anonymous, evergreen background to our lives, but both are so invasive in this part of the world that they should probably be outlawed. Several species of osmanthus make good hedges as well as specimen plants. Osmanthus heterophyllus is adaptable to sun or light shade. In the cultivar ‘Variegatus’ the holly-like leaves are generously marked with ivory. This and gold-splashed ‘Goshiki’ are two of my favorite shrubs for patio containers. 

And why would you let those containers languish all winter empty or, even worse, still harboring sad remnants of summer? Camellias adapt well to pots in sun or shade, and a camellia in bloom makes a very nice gift. Grays Garden Center has a fine selection. Other good contenders are Tasmanian pepperbush (Drimys lanceolata, excellent for smaller pots) and gold-spotted  Aucuba japonica ‘Variegata.’ Aucuba has large, glossy leaves and needs some shade. Culinary or Mediterranean bay (Laurus nobilis) and boxwood (Buxus spp.) are classics for more formal pots and tubs. Both withstand clipping into balls and pyramids.

So, of course, does yew, which is a conifer. With a few exceptions, conifers have leaves that are needle-like (think Douglas fir or Colorado spruce) or small and scale-like (as in arborvitae or Western red cedar). Most full-grown conifers are, in their normal state, very large. But conifers, far more than deciduous trees, seem to lend themselves to spontaneous miniaturization. Fanciers have for centuries collected these mutated forms and propagated them from cuttings, providing gardeners and bonsai enthusiasts with a wealth of material that can be bun-shaped, prostrate, weeping or narrowly upright, and all in a variety of growth rates, from painfully slow to moderately speedy. 

Some people like the idea of a living, potted Christmas or Solstice tree they can save for another year or two and then plant outside, but there’s a catch. Conventional Christmas trees — usually Douglas fir, true fir or spruce — will grow into monsters that suck all light, water and nourishment from a significant area of your yard. Unless you have a reforestation project under way, how about choosing a non-conventional conifer? A dwarf pine, perhaps, or dwarf Alberta spruce. Bloomers Nursery is a good place to buy a variety of evergreens in pots.

A dwarf Hinoki cypress (Chamaecyparis obtusa) would be a good choice, especially ‘Gracilis’ or the smaller ‘Nana Gracilis.’ Both have an irregular, slightly open structure, well suited for dangling ornaments. ‘Nana Aurea’ is one of several similarly structured Hinokis that sports golden foliage. A particular favorite of mine is Chamaecyparis obtusa ‘Coralliformis.’ ‘Torulosa’ is the same or similar. Both have contorted, cord-like foliage that provides a unique texture.

The ultimate height of Hinokis when planted in the garden is hard to predict, but in my experience it tends to be greater than the label claims. Variables may include soil type, moisture level and the stock from which your particular specimen was cloned. ‘Kosteri’ is a widely grown smaller form that is supposed to reach five feet “eventually,” but I have planted locally raised Kosteris that surpassed six feet in five years. 

Properly cared for, Hinokis will live for years in a container, and unlike many conifers they tolerate light pruning. They make great additions to patio screening, and go well with bamboo and Japanese maples. Other small and medium sized conifers do very well in pots, too. In fact some are easier to please in a pot than in the ground, especially in our frequently rain-soaked gardens. This certainly applies to dwarf, upright junipers and also to the many handsome cultivars of Port Orford cedar, also known as Lawson cedar, which is quite susceptible to root rot in ordinary soil. ‘Ellwoodii’ is one of several columnar forms with vertical fans of blue-gray foliage. Others have eye-catching yellow foliage. All the upright forms are perfect for pots when you need a formal look.

Rachel Foster of Eugene is a writer and garden consultant. She can be reached at rfoster@efn.org