Silver Feather Grass- our favorite ornamental grass. From humble blue leaves that form an upright grassy clump stems rise to 4′. As the flower open they unfurl- curling 18″ long horizontally and covered in soft downy hairs. The slightest wind puts these streamers into graceful motion. Blooms June-July. When the flowers ripen and begin to detach they can be gathered and made into a bouquet and the tails will curl up and form a soft tan haze. An arrangement lasts forever. Often self sows in open conditions- and this is good because it is not an easy grass to germinate and does not work from division. Easy to move when small. Give it an open position where you can observe the streaming flowers unobstructed. Very hardy and little summer water once established. Full sun. Semi-evergreen foliage in winter. High deer resistance. Spectacular grass. See video below.
Biome: Hot Aspects
Its surprising in our climate that heat is as big of an issue as it is. But there are scores of sunburned and toasted plants littering our city by the end of summer. We average just 2.o” of rain during June-August and you have to take into account reflected heat. That could be heat emanating from an asphalt street such as occurs in a hellstrip or the accumulated heat of a hot wall. Both can conspire to fry plants. Luckily, we grow a LOT of plants adapted to excess heat. These plants won’t fry on the first day above 95ºF. Some plants revel in reflected heat, they come from hotter climates and need warmth to both bloom and to ripen wood for winter. That means it receives enough heating calories to ensure winter hardiness. Currently, Portland averages 14 days above 90ºF per year. By the next decade that number will have more than doubled. Part of gardening with climate change is to anticipate those effects and adapt to them. Increasingly, we will be considered a hot summer climate. We should garden accordingly.
Climate Adapted Plants for Gardeners in the PNW
Stipa gigantea
This is the giant straight species that is so popular for its soaring silver stems and golden drooping awns. To 12′ tall in bloom from a tight but large basal clump of fine deep green leaves. Perfectly evergreen with a great winter appearance. Very easy to grow grass that provides spectacular garden effects. Incredibly drought tolerant in any well drained soil- including clay if it is not allowed to become bone dry concrete. Flowers make a great see through “scrim” in gardens. Fun to grow. Moderate deer resistance.
Stipa gigantea ‘Little Giant’
As if a wonderful grass couldn’t get any better this smaller version thrills us with so many more applications. A low clump of arching dense dark green evergreen foliage has a nice presence year round. In spring and continuing all throughout summer into autumn 3′-4′ spikes terminate in clouds of metallic golden awns. They sparkle in full sun and sway in the breeze- but are determinedly upright. The basal clump of leaves spreads slowly to 2′ wide in 5 years. Full sun and well drained soil- bud adaptable to anything but a bog. Evergreen. Cut back spent flowers in winter- or let them stay and wave around beckoning birds and wildlife. Moderate deer resistance. Little to no summer water when established.
We have been so impressed with the performance of this small evergreen tree species that when we saw this charming narrow leaved form we snagged it. An upright growing but not wide tree to 18′ tall. The thin leaves are 4mm wide but up to 6cm long and are thinly produced so that the tree has a fine texture and is even better to view the late winter and early spring red brushy, flowers. Moderately fast growing it is also very drought tolerant. Water to establish and in summer or to speed growth otherwise it can get by on natural rainfall. Very neat and tidy and cold hardy to -5ºF. This tree is a good candidate for areas affected by subfreezing east wind- its exceptionally tolerant of that for a broad leaved evergreen. Full sun to high overhead shade ( with less of the red flowers). In time the cut branches can be brought inside and forced into bloom for arrangements. Not deer food, but i’m not as familiar with this form. Unusual, tough and beautiful. Narrow leaved Sycopsis. Tolerates many soil types including heavy soils in upland situations. SW China
Symphoricarpos albus
Common snowberry is very widespread in our state and is found in a host of biomes This small, deciduous, suckering shrub begins spring with leaves of the freshest green, so fresh they flutter on the late spring early summer breeze. After several weeks of foliage the small white tinted pink flowers are shaped like small bowls and line the stem at every leaf axil. These morph into plush, plump pure white berries that are quite a bit larger than the relatively insignificant flowers. The berries (drupes) are perched in groups on the stems. Their pure white hue is easy to spot for humans and especially birds.They relish the berries while they are toxic for humans. To 32″ tall forming a dome shaped suckering shrub twice as wide. Water to establish the first season then none in subsequent years. Mulch heavily. The berries last well into winter before becoming animal snacks. The gray thin arching stems create a haze on the forest floor that becomes acid green as leaves appear. Spreads by stolons underground to expand its territory. Its adaptable to both upland quite dry situations as well as vernally wet spots in floodplains and fields. In the Willamette Valley its common associates are with Pseudotsuga menziesii (Douglas Fir) Quercus garryana ( Oregon White Oak) and Fraxinus latifolia ( Oregon Ash) as an understory component. Its tolerant of dense shade as long as its deciduous to full hot sun, Very well adapted to the driest summers. In summer the acid green leaves change to a dark blue green and are often afflicted by a strain of powdery mildew- my whole life I’ve known this shrub and I’ve never seen powdery mildew cause any permanent damage- mostly its just a poor aesthetic look for late summer to autumn. Fall color is soft yellow and brief. Branches may be carefully cut in berry and will hold them in arrangements for quite a few days. An excellent forage and cover plant for native fauna. A great native shrub for beginners. This is the taller form of the two species that we grow. Native to the Portland city limits. Moderate deer resistance. One of our best shrubs for seasonally dry shade. Oregon native plant.
Pacific Aster. Our selection of a widespread beach aster species that circles much of the temperate Pacific Rim. This form tops out at a compact 30″ on an upright plant that forms expanding clumps in rich to average soil ‘Short Sands’ is a purple form from seed of a very dark purple specimen that Greg found. It is by far the darkest purple that we have encountered in this species. The majority are white to very light lavender. Most often its habitat is adjacent or very near the coastal strand. Its adapted to all kinds of soils from sand to clay and it appreciates deep infrequent water during the summer season. Blooms begin in August and open until mid November. This aster is often seen along the sides of HWY 101. In fleeting glimpse you can capture small periwinkle daisies late in the season. A pollinator master piece. All sorts of natives recognize this showy perennial. Full sun to light shade. It seems to be most vertical in full sun and average soil. Over amended soils, too much water, or too much shade will lead to a splaying flop. The flat upturned daisies come in rows of two for a fuller look and are a natural landing pad for butterflies. Winter deciduous, very tolerant of dry conditions when established but does better with deep infrequent summer drinks. Cut back hard in spring- a new batch of leaves will just be arriving. This sophisticated native is at home in pampered borders or wild areas. Associated plants in habitat are Mianthemum dilitatum, Calamagrostis nutkensis, and Vaccinium ovatum. Its habitat is dwindling as Everlasting Pea (Lathyrus latifolius) and Ox Eye Daisy (Dendranthema) have crowded this special plant out Excellent garden plant. Oregon native plant
Xera Plants Introduction
Symphyotrichum subspicatum ‘Sauvie Star’
One of our color selections of the locally native Douglas Aster. This cultivar originates from seed collected on Sauvie Island. This is the predominant wild Aster of the Willamette Valley. A boisterous long blooming perennial at home in wild areas. Rich to average soil with light summer water. Blooms- in this case, periwinkle blue open in early August and continue unabated to October. They are beacons to all pollinators and are constantly in motion as they bloom. To 32″ tall forming wide patches. Runs by underground stolons. Nice cut flower. Wetland remediation, forest verges, denuded road cuts. Those are jobs for you Douglas Aster. Oregon native plant.
Xera Plants Introduction.
Tanecetum densum ‘Amani’
You can’t resist the finely divided feathery nearly white foliage of this great small scale ground cover. Foliage to 4″ tall and spreading to 2′ wide in full sun and well drained soil. Light summer water. Small flowers lacking petals have a center of off white/gold in early summer. Excellent performance on slopes as well as rock gardens. Evergreen. Loves life in the hellstrip.
Tetrapanax papyifera ‘Steroidal Giant’
Big form of the already big Japanese Rice Paper plant. Enormous 3′ wide leaves look jurassic and erupt in spring from seemingly spindly bare stalks. Fast growing deciduous shrub/tree that also suckers to form wide colonies. To 18′ tall in 5 years with multiple trunks in deep rich soil with regular irrigation. Full sun to part shade. Be aware that this plant travels. It moves stealthily underground and can be many feet away from the parent plant before you notice it. The more root disturbance the more errant suckering. Give it room and respect. Light summer water. Almost blooms each autumn before running out of heat and daylength. Bare sticks in winter. It may also be contained the same as bamboo. It is, however, easy to pull the suckers by hand. Wait until they grow several leaves and then grab it by the stem and wiggle, slowly at first then in wide arcs and pull. It will pull right up. Also, there is a conspicuous indumentum (brown fur) all over the plant and especially the leaves, these tiny hairs when rubbed off or disturbed can cause skin irritation in some people. Wear gloves and a rain coat while pruning.
Teucrium aroanum
Low ground cover Germander that is at home in hot sunny aspects in well drained conditions. The fine gray foliage rises to 5″ tall and forms a spreading plant. Beginning in early summer and extending to fall soft purple to lavender clusters of flowers cover the surface of the plant. Though small this plant is a huge hit with pollinators. Full, hot sun and light summer water to establish. Not a fan of heavy soils and sodden conditions In the wild this plant is primarily a resident of rocky sites and hillsides of the Mediterranean. This ever gray perennial is good looking in winter. Foliage is aromatic and has fruity tints to the fragrance. Mix with other smaller rock garden plants or develop a small area that acts as a groundcover. Loathes shade. Good container or trough plant. Grows up to 18″ wide in several years. Pollinator masterpiece. Moderate deer resistance.