Such a cool tree for small gardens. Upright growing and then branches that also turn vertical fairly quickly- kind of like an upside down candelabra. The lush evergreen foliage is composed of palmate divided leaves which droop gracefully and give the plant a lighter mein. In summer masses of orbicular off white aralia flowers appear en masse at the branch tips. They are pollinator heaven. And they turn into clusters of black berries consumed by birds. To 16′ tall and half as wide. Perfectly hardy to cold, but can become semi-deciduous below 10ºF. New leaves come quickly in spring. Fast growing tree for rich soil and regular summer water in full sun to high overhead shade in woodland conditions. This pretty tree has a promising future.
We’ve grown this extraordinarily cold hardy european olive selection for years. And its performance in the city of Portland is stellar. Fast growing somewhat wild looking, ever-silver tree to 20′ tall and 15′ wide in 10 years. In time it develops a gnarled trunk adding to the trees character. This is a self fertile selection and sets fruit very heavily even on singular trees. The fleshy moderately sized fruits are most prized for oil. They may be brined. (Follow any recipe on the internet). Be aware of autumn and winter fruit drop- not for patios, instead plant a large ground cover at the base for the unwanted fruit to drop and hide. Birds will eat the olives too- especially larger birds. Overall, its a pretty tree when the thin blue gray leaves are tossed by the wind revealing their silvery undersides. Fast growing especially if watering is frequent and diligent during youth. Water like crazy for the first summer to spur growth and establishment. Olive trees gain cold hardiness with age/size. Small plants are tender to dead below 15ºF but a three year old, well watered of the same variety will be undamaged at much colder temperatures than that. Excellent performance in ice and snow (see picture below)- bends but does not break. Protect containerized plants from temperatures below 15ºF. Drought adapted when established. A warm position.
Long ago I dismissed this tall sweetly scented Tea Olive as hopelessly tender in our climate. Then in a garden in Lake Oswego under towering firs I ran head on into an 18′ tall perfectly happy specimen. Looks like it had never suffered damage. It was just a really nice broadleaved evergreen tree. Copious amounts of small off white flowers crowd the stems beginning in autumn in our climate and then sporadically until spring. The POWERFUL fragrance they emit is that of apricot/freesia/rose and it travels- detectable 20′ away when in full bloom. To 15′-20′ tall apparently. Requires protection as a young plant and it really should not be in an exposed site. Instead locate near a house wall- where you can open the windows and let the perfume flow- and gain added protection. Gains much, much, greater hardiness with age. Summer heat seems to play a role- the more heat in summer the hardier in winter. Full sun to high overhead shade. Grows 2′-3’/yr. when young- aided by consistent summer water. Otherwise established trees need little. Not a plant for cold gardens.
Amazing hybrid Tea olive that inherits the insane perfume of O. fragrans and cold hardiness from O. heterophyllus. Fast growing columnar broad leaved evergreen shrub to 16′ tall x 5′ wide in 7 years. In time it can make tree like status to 20’+ tall. Otherwise pruning easily keeps it much smaller. In Oct-Dec. tiny parchment colored flowers crowd the stems and emit the sweet penetrating perfume of Freesia and apricots. On mild days its detectable up to 20′ away. Juvenile foliage is prickly but as the shrub matures it develops entire leaves with a smooth margin. Young plants grow about 2′-5′ per year depending upon summer irrigation and soil fertility. This shrub is always at its most lustrous and healthy appearance. Average well drained soil with light but consistent summer irrigation. Totally summer drought tolerant when established. Excellent screen, hedge, or just as a large specimen if you love perfume. Bark/stems are a handsome pale tan- good contrast with the deep green leaves. Avoid direct exposure to subfreezing east wind. Long lived.
Pacific ponderosa pine is a lovely tree native west of the Cascades from about the Portland area (with some outliers farther north) south to northern California. Our form is from locally collected seed. Slow growing in youth this pine picks up speed in its teens and grows almost exponentially from there. Pacific ponderosa pine is known for it tall straight crowns of lush green needles in clumps of three. This tree is excellently adapted to our winter wet/summer dry climate and even small trees can endure the very longest, driest, hottest summers with no visible stress. Its adaptable to all types of soil – not fussy and is even found in the most well drained stranded flood cobbles of major rivers. To 125′ in time with ulitimate height of close to 200′ in great age – expect a 3′ tall tree to be about 15′ tall in 10 years. Full sun- not very shade tolerant and when planting with other trees anticipate at least a 25′ wide crown in the future. Needles can drop profusely in September which is a bit of a mess. Take note of this. Underplant with other drought adapted natives. Water to establish for the first summer then none in subsequent years. A regal pine that is among the tallest in the world. Oregon native plant.
Gray Pine or Foothill Pine native almost exclusively to the mountains of California- but there are several outlying native populations in Douglas, Josephine and Jackson, Counties in Oregon so we can claim it as our own as well. Known as the tree that casts no shade, its almost completely true as the long gray needles allow almost all light through. Large pine tree with gray foliage- usually forks about 1/2 way up into two main trunks, these are buttressed to support the huge cones which can weigh 5lbs or more. Excellent performance in the Willamette Valley where many are seen around old farm houses and older neighborhoods. Perfectly hardy to cold in our climate and incredibly drought adapted. In fact it shuns all irrigation and is ideal for hot dry locations. Grows very fast in youth, settles down a little with age. Its ultimate height is around 35′-45′ in our climate. A smokey, silvery, shadeless skyline tree. Oregon native plant.
Sophisticated winter blooming tree that we love for its incredibly sweet spicy scented flowers. Double pink flowers are conspicuous and perched perfectly on the green twigs of this asian flowering apricot. Flowers appear in December in mild years as late as February in the coldest. Flowers last forever in the cool winter air. Each spicily scented flower has a prominent boss of white stamens. Its the details man. Flowers are hardy to around 20ºF- closed buds are substantially hardier and will unfurl when the weather warms. Moderately fast growing tree to 18′ x12′ in 10 years. Appreciates deep, rich soil and definitely weekly summer water in its first few years. Fall color is pale yellow. Inedible ornamental fruits often follow the blossoms. Japan.
Canyon live oak is a vastly underused, beautiful evergreen native tree. Found from Lane county, Oregon south through California, slight parts of Nevada around Lake Tahoe and sporadically in Arizona and even New Mexico. This venerable tree is found on the steepest slopes of canyons and mountain ridges. In Oregon it represents the northern most native Live Oak or evergreen oak in North America. Leaves are glossy army green on the the top with a conspicuous furry gold underside. This is a rugged, tough tree that should be used in both gardens and as a street tree. In the Alameda neighborhood in Portland there is an ancient specimen to 60′ tall and wide with a large trunk. This heritage tree was reportedly brought to the city from southern Oregon via horse and wagon. Slow growing in youth it picks up speed exponentially several years after planting. To 40′ x 20′ in 30 years with a broad spreading crown. In the wild it often forms a gnarled multi-trunked rounded outline. Its very possible to train this tree to a single trunk/leader to extend the crown skyward. Extraordinarily cold hardy enduring temperatures slightly below 0ºF with no difficulty. The large acorns are born in a showy golden hued furry cups- and are produced profusely in banner years. Water to establish for the first season then none in subsequent years. Full sun. Beautiful, native Oak that we cherish at Xera. Oregon native plant.
Oregon white oak. A monarch of a tree locally native and forming Oak Savanna communities in the Willamette Valley that preceded European development. Slow growing tree of great age and grace. Deep green foliage forms dappled domes in the high rounded canopy. Birds and wildlife adore this completely summer drought adapted tree. To 130′ but not in your lifetime. Our acorn source is local. Whitish bark in patches and it will often develop pure white patches at the base- an outlet for sodium from the constantly saturated Oregon winter soils. Tolerates the most impenetrable clay and shuns summer irrigation. Fall color is russet orange. Grows just 2′-3′ a year in youth -if really happy. This as all oaks has what are referred to as banner years. In certain years huge amounts of acorns are produced. This is thought to overwhelm predators and at least a fair amount can germinate. Famous for its moss covered enormous branches which have been likened to the perfect depiction of a Grimm’s Fairy Tale. Oregon native plant.
Silver Leaf Oak from Arizona is a favorite tree at Xera. Tall, rounded evergreen tree with skinny but thick leaves that are sage green on top and silver white on the underside. Its handsome all the time and even prettier when the gold catkins protrude from the foliage in spring. Naturally develops a straight trunk. Fast growing tree in our climate to 35′ in 12 years. Casts dense shade but tolerates limited summer water. Extraordinarily cold hardy. It has endured subzero readings in Eugene without injury and I even encountered one in a garden in Denver. The leaves were kind of toasted from the previous winters -17ºF(!) but it was obviously thriving. Native to the mountains of SE Arizona at very high elevations and that translates to LOVE for our climate. Exceptional leaf form and shape. Be aware that in time this tree can cast quite dense shade. Wonderful on hot summer days but also inhibiting sun loving gardening. Makes you think. Wonderfully pest and disease resistant foliage- it always looks good.
Photo credit: Amy Campion