Friday, July 3, 2009
Broadleaved Evergreen Trees- conclusion
Magnolia grandiflora / EVERGREEN MAGNOLIA
This one, at least, is common and perhaps overused, likely for want of other choices. It is certainly a dramatic beauty, with large, glossy leaves and huge, deliciously fragrant white flowers. There are many cultivars, most with intermediate foliage and pyramidal crowns 40-60 ft. tall. Dwarfs like 'Little Gem' are popular for restrained size, though this one sometimes has a problem with fungus that thins the foliage. "Majestic Beauty has the largest leaves, but can be pale and shy-flowering here. 'Bracken's Brown Beauty' and 'D. D. Blanchard' are dense and narrow , with striking rust-brown leaf undersides. Evergreen magnolia is amazingly hardy and adaptable, but trees on dry hardpan may be thin, yellowish and stunted.
Magnolia virginiana v australis/ EVERGREEN SWEET BAY
This harder-to-find magnolia may be a more useful tree in most situations. Smaller, narrower leaves than those of M. grandiflora, silvery below, give it a more intermediate texture. Small, fragrant white flowers open through the warmer months. Most trees reach a narrow 30 ft. or so. Though a swamp tree, it is remarkably drought-hardy. Cultivars such as 'Henry Hicks' are typically evergreen though they may not fall under variety australis. Best to buy M. virginiana in late winter to be sure of its leaf retention.
Maytenus boaria / CHILEAN MAYTEN
Willowy grace is the feature of this small tree. Narrow, 1-2 in. long leaves in bright green make billowy streamers arching from slender branches. Some plants are full and upright, others, especially when older, take on a weeping-willow habit. Mayten tolerates wet soil as well as drought, though it is very slow on dry hardpan. Trees in shade or moist soil may reach 40 ft. while those in tougher circumstances stay 15-20 ft.
Michelia maudiae / SMILING FOREST LILY TREE
As charming as its common name, this small magnolia relative ( now officially a Magnolia, it seems) grows to 20 ft. or so, with glossy, 4-6 in. leaves and large, fragrant white flowers in spring. It is relatively new and scarce in the Northwest, but established trees, seen here and there, have done well and the tree seems hardy in at least our warmer zones. A few street trees in Portland are thriving without water.
Nothofagus dombeyii / COIGUE
Most of the southern beeches, Nothofagus, are tiny-leaved evergreens. This Chilean species captivates nearly everyone with its deep green, 3/4 inch leaves in neat, flat fronds on slender, undulating branches. Young trees race to a height of 80 ft. or more, with many smooth, gray ascending branches. Old specimens in Chile resemble gnarled oaks. The only hangup with these trees, besides rarity in nurseries, is their vulnerability to high winds; a spot where the prevailing winds are filtered is best.
Related to avocado and other subtropical beauties out of our reach, this rare Chinese tree is hardy in all the warmer Northwest zones. Its lush, rounded crown in made of slender, glossy, aromatic leaves that are silver-blue beneath. Blue, olive-like fruits ripen in fall. The tree reaches 40 ft. or more, drought-hardy and happy in sun or shade.
Photinia serratifolia / CHINESE PHOTINIA
Popular in the 1950's and earlier, this handsome tree deserves a comeback. Its large, glossy leaves, open in February and March in glowing shades of golden orange and coppery red. White flowers in wide clusters follow. Dense and round-headed, Chinese photinia reaches 30-50 ft. tall. Once shunned for mildew, it is seldom troubled by it in sunny, unwatered sites. Its hybrid offspring, the ubiquitous P. x fraseri makes a good small tree, too, but is increasingly subject to disease.
Quercus / OAKS
Here is the largest group of broadleaved evergreen trees for this area. At least half of the 600 oak species are evergreen; only a few are readily available though many others are sold by specialty nurseries. Colvos Creek carries many in small sizes.
Quercus chrysolepis / CANYON LIVE OAK
This native of sw Oregon and California has small, holly-like leaves on rather gnarled branches. It reaches 60 ft. or more, with a beautiful framework of smooth, very climbable branches. Bushy when young, it requires some early pruning to establish a straight, clear trunk for urban situations.
Quercus hypoleucoides / SILVERLEAF OAK
From the Southwest and Mexico comes this beautiful and easy-to-grow oak. Slender, tapered leaves are leathery gray green above, velvety white below, very nice in the wind. A layered, pyramidal crown reaches 20-30 ft. rather quickly, eventually topping out at 50-60 ft. This great tree is quite adapted to the Northwest and is thriving, though still rare, around the region.
Quercus ilex / HOLLY OAK, HOLM OAK
This sturdy oak of the Mediterranean region is planted in mild zones around the world and is seen here and there on the streets of Portland and Seattle. Its variable leaves are small, oval to tapered, toothed or not, and deep gray green above, pale below. The crown of a holly oak is usually dense and the trees have sometimes been sheared into formal shapes. Eventually, the tree opens up some and takes on more character. It is very adaptable and drought hardy, but trees brought up from California trained to a stake often have slender, weak stems. Better to take a bushy specimen with stout trunk and gradually prune to the desired form.
Quercus laurifolia / LAUREL OAK
This is perhaps the best broadleaved evergreen tree for streets and other city uses. Its narrow, grass-green leaves on slender branches thin out in winter, letting in light yet retaining a leafy green aspect. It makes a broadly pyramidal crown to 60 ft. tall and adapts to nearly any soil, from wet to dry. Though a native of the South, it is perfectly hardy here.
Quercus myrinaefolia / BAMBOOLEAF OAK
Slow and dignified, this Japanese tree eventually reaches 40 ft. tall with round outline. Narrow, tapered leaves are glossy bright green above, silvery below, and point slightly downward in an elegant pattern. This oak responds beautifully to rich moist soil but manages well in most conditions and is drought hardy once established. Several related Japanese oaks, Q. glauca, Q. acuta, Q. gilva and Q. stenophylla are all good, too.
Quercus suber / CORK OAK
Bottle-stoppers and flooring are made from the bark of this Mediterranean tree. In deep ridges and furrows it covers a beautifully gnarled and angled trunk that carries billows of gray-green, holly-like leaves in an open, 40-80 ft. crown. This is a character tree, best as a specimen, hard to use on streets unless pre-trained to a straight trunk. It is hardy in all warmer Northwest zones.
A small tree related to witch hazel, this rather plain plant is never the less pleasing and quite hardy. Narrowly ovate leaves in deep olive green hang gracefully from slender branches to form a not-too-dense, rounded crown. Tiny puffs of orange flowers in winter reward close inspection. Drought-hardy and nearly pest free, the sycopsis shouldn't be so rare. It slowly reaches 20 ft. or so.
Umbellularia californica / OREGON MYRTLE, CALIFORNIA BAY
A native of California and southwest Oregon, Oregon myrtle can be a large shrub on dry hillsides or more often a tree to 80 ft. or more with moisture and better soil. Foliage is similar to that of Laurus, the Mediterranean bay, but more tapered, a bit brighter green and much more wild in aroma. Tiny winter flowers are followed by green, inch-wide fruits with large seeds that sprout readily in the vicinity. This handsome tree needs lots of room -it's hard for many plants to grow in its pungent shade- and the tree can be stunted by clay hardpan.