Subalpine Rose Spiraea is native to the higher elevations of the the Cascades. Above 4500′ in sunny, moist glens it makes carpets of deep rose pink umbels from low rounded shrubs. To 30″ tall by 4′ wide in garden conditions, Rich soil with regular irrigation. Moderately fast growing to this dimension. The emerging soft green leaves take on hints of blue as they mature. Bloom at low elevation is May-July but in its highest native haunts bloom can be delayed to late summer. Deciduous shrub with wonderful orange/ red fall color if brief. Easy to grow native garden plant with regular irrigation. Established plants can take deep watering every two weeks. Remember that this as with all Spiraeas have little tolerance for drought and they don’t necessarily wilt going straight to crispy (a look not as fixable as wilting). Mulch heavily for the first few seasons. Avoid blasting, reflected heat and and hot dry situations. Wonderful combined with Rhododendrons and Azaleas for similar cultural conditions. In its native haunt it can be found with Pacific Rhododendron, Helenium, Delphiniums and Veratrum. I’ve never seen it afflicted by disease. Watch for aphids, hose those off if they appear. Beautiful in bloom. Very cold hardy. Oregon native plant.
Plant Type: Shrub
Shrubs are the backbone of Pacific Northwest Gardens. We’re able to grow an incredible amount from all over the world. Evergreen to deciduous the choices are vast. We focus on mostly (but not all) low water species and many native western species. Shrubs are often much less thirsty than other plants and live for a long time if properly sited. They can sport amazing foliage or showy flowers. From Manzanita to Ceanothus and even Grevilleas nothing makes a garden look more western. Our choice of shrubs is from years of experience growing them in our own gardens.
The best treatment leads to success
Treat all shrubs well when you plant. Dig a large hole and apply ample mulch and water to establish well. Do not let the shrub dry out completely until you are sure it is established and make a point to mulch each shrub. This is particularly important if you are creating a hedge or massing shrubs. Treating them all consistently well is the difference between continuity and chaos.
Pruning shrubs 101
The most daunting thing about growing shrubs is pruning. I try to include information about pruning each individual plant – but there are several rules that I adhere to when I prune a shrub that I am unfamiliar with. First, if you do not know the shrub let it bloom. Take note if it blooms on established wood from the previous season or if it grows and then blooms- an indication that it blooms on new wood. If it blooms on wood from the previous season – or ‘old wood’ then you can prune it directly AFTER blooming is done. That way you have less chance of eliminating bloom for the coming season and if it blooms on new wood you are safe too. Plants that bloom on new wood can be pruned in early spring some examples are Lagerstromia, Abelia, Indigofera. Once you understand this it makes pruning MUCH less intimidating. Make sure that you have very sharp pruners and it hurts nothing to sterilize them first. 1 TBS bleach to a bucket of water and a quick dip. Pruning can introduce disease so this is prudent.
New compact plants preclude pruning
Over the eons and more so lately nursery people have been selecting shrubs for more compact habits as well as vibrant bloom. Take advantage of these slower and smaller growing tendencies in the garden. Choosing the right size plant saves work in the future and eliminates the need to prune at all.
Many shrubs will morph into trees over time
In time many shrubs can pose as small trees and this should always be figured into a design. It is far easier and more natural to let a shrub become arboreal than the tortured look and continual work of making it small. Some shrubs that go on to become trees in time are Osmanthus (many) Phillyrea, Camellias, Manzanita (many). Leptospermum. Many reach tree like proportions in a decade or so. They may have their lower limbs removed to reveal shady planting space beneath and to accentuate the view of the bark which can be quite showy. They may also be trained to single leader to produce compact appropriately sized trees for courtyards and smaller gardens for a more formal appearance.
Topiary- a precise art
Topiary is an art that we dabble in at Xera. More than just torturing plants it is a process that takes a bit of planning and plant choice. It introduces a little discipline to the gardener in the form of regular maintenance and the effects are worth the effort. For the best effects and adaptability we use the tried and true forms of myrtle. They’ve been the subject of topiary for eons and we know why. They take a lot of pruning with no harm. They live long lives in containers are drought adapted and we choose the cold hardiest cultivars. The flowers which are adorable are in perfect scale with the leaves, Topiaries can introduce small amounts of formality in a garden and we love the way this plays in larger wild landscapes.
Rely on our soils own fertility
Shrubs in our climate and soils for the most part do not need fertilizer. In fact, over time I’ve seen more ill effects of overfertilization than I have seen benefits. Most often the plant is not getting enough water and the solution is a layer of mulch and a more consistent irrigation program. Often very drought adapted shrubs will react to added water in a dramatic way- Ceanothus, Grevilleas, Leptospermums, Arctostaphylos are genus’ that respond to water in a big way- in fact they react as if having been fertilized with no improvement to the soil at all and they explode in growth. Therefore, we recommend no supplemental irrigation for these genera when established but if they are slow to take off don’t be afraid to water, Irrigation requirements are in each description as well.
Shrubs- furniture for the garden
We need to shift our definition of shrubs. For too long they’ve been the tortured class of plants. The recent trend of grasses mixes excellently with shrubs but not if they are pruned into submission. Take the time to pick the correct plant for the site and be realistic. Plants grow fast in Oregon.
Climate Adapted Plants for Gardeners in the PNW
Spiraea thunbergii ‘Fujino Pinky’
This is a charming hardy, deciduous shrub with quite a few fine attributes. In late winter to early spring red flower buds line the arching fine stems and open to white/light pink. The effect is a classic apple blossom scheme. The fine leaves are thin and and a pleasant fresh green in summer. I think its finest hour is autumn when the whole shrub becomes a glowing ball of red/ orange/ pink. The chemical that causes the the pink in the flowers is most evident in the fall color. Tough rounded and then arching shrub of fine texture. Blooms on wood from the previous season, prune directly AFTER blooming if necessary. Size is somewhat dependent on irrigation. To 4′ x 4′ in 5 years in rich to average soil with regular summer water to establish. Then just avoid severe aridity. Long lived, cold hardy plant that is best with a hard pruning every 6 or so years to refresh. Good for wild areas, not deer resistant but admirably adapted to dryness. Excellent performance in the Columbia Gorge and east of the Cascades. Mix with Spiraea betulifolia var. lucida for summer bloom but a simultaneous spectacular long show in fall. Native to Japan.
Spiraea x pyramidata
This is our local form of the Pyramid Spiraea an attractive naturally occurring hybrid between two local species. Spiraea douglasii (dark pink flowered) and Spiraea betulifolia var. lucida (white flowered). Its a larger plant and much more controlled than its parent S. douglasii and it inherits some of the drought adaptation of Birch leaf Spiraea. To 5′ tall and 4′ wide this upright growing shrub produces pyramid shaped inflorescences of the softest pink- intermediate between the two species. This form was found just east of Portland. Full sun and occasional deep soaks in dry summers. Tolerates part shade at the expense of a tidy, upright habit. Blooms on wood from the previous season, prune if needed after flowering. Adaptable to wild areas. Deciduous shrub that turns to tones of yellow and flaming orange in mid autumn. This twiggy shrub would make a great hedgerow plant. Blooms late May to early July. Flowers turn to tan seed heads that persist on the plant. Cold hardy and not difficult to grow. Not bothered by pests or disease. Not fussy about soils adaptable from sand to clay. Oregon native plant.
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.
Symphoricarpos mollis
Creeping snowberry is widespread in western Oregon and indeed throughout the state. Its a low suckering deciduous shrub that can occupy large areas. To 30″ tall spread is indefinite in rich to average soil with regular water for the first year to establish. Mulch is extremely beneficial and will suppress weeds for the first few years which can arrive in the middle of a patch of this spreading plant. Leaves are fresh green in spring turning blue green with the heat of summer. Small pinkish flowers occur in late spring and morph over the summer into plush white squishy berries. They line the bare stems and are showy until birds make off with them or they remain and rot. The berries are toxic for humans. Fall color is light yellow to very little. Common on undisturbed slopes on the edges of the valley and in the eastern foothills of the Coast Range and western Cascades. Snow berry is often afflicted with powdery mildew in the driest parts of summer. No harm will come to the plant. A wonderful habitat plant. Oregon native plant.
Telopea x ‘Braidwood Seedlings’
Waratah of Australia, this extraordinary shrub produces some of the most alluring flowers in the flower kingdom. A tall growing evergreen shrub with handsome leaves. In spring and often again in late summer crown shaped flowers emerge purple and open to circular red flowers at the branch tips. These are seedlings of Telopea x ‘Braidwood Brilliant’ which is a hybrid selected for excellent cold hardiness for the cut flower trade. Protea- which means you should avoid fertilizer and too much compost. Rich to average soils- pure loam is ideal in a protected location in full sun to part shade. Avoid reflected heat. Light summer water. Not the easiest shrub to establish but the care and patience are worth it in the end. Cold hardy to approximately 5ºF. Protect from subfreezing wind. Amazing cut flower that lasts for weeks in a vase- if you can spare a stem. Excellent performance at the Oregon Coast. To 12′ x 8′.
Xera Plants Introduction.
Ternstroemia gymnanthera
Obscure but exceedingly handsome and reliable shrub for hedges, specimens, eventually a small tree. Rounded leaves are good looking year round and especially when they first emerge brilliant salmon red before settling to dark green. This is the most showy display on this plant and it lasts for weeks. In mid-late summer small pendant white/cream flowers are nestled among the leaves, you really have to look to see them. Clean evergreen whose foliage is never marred by fungus or cold. Full sun to high overhead shade. To 8′-10′ tall and about half as wide. With great age and no pruning it can achieve small tree status and it forms attractive cloud like crowns of foliage. As a hedge it excels. Plant 2 gallon plants on 3′ centers and mulch. Irrigate about once a week until you see good new growth. Established plants are very tolerant of dry conditions. Theaceae- Camellia family. Excellent cold hardiness to 0ºF, tolerates some subfreezing wind. Excellent companion plant for Rhododendrons, Pieris, Illicium. Full sun to quite a bit of shade. Native to Japan. Good looking tough plant. Light deer resistance.
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.
A stylish shrub/subshrub that is native to the drier parts of New Zealand, and offers great fine texture. The stems which are the only thing that differentiates this from the genus Coprosma- they are square. are golden orange woody stems that rise up to about 4′ tall by 3′ wide. Tiny round green leaves decorate these stems and in late spring and early summer small white flowers appear in the leaf axils. This plant can quickly return from the roots if chopped back severely or frozen to the ground. Established plants can regain their stature in several months. Average to enriched soil that is never boggy in summer. The fine foliage common adaptation in New Zealand, most likely the fine texture of the shrub was to foil grazing giant moa birds and other predators. Very good in containers ( it will be less hardy in a container as with everything) and it can be crowded heavily and still thrive. In the ground give it enriched soil and regular summer water for its first season. Let it grow as much as possible and develop a resilient root system- in the case of an arctic event it will be well prepared to regrow.. Mulch in fall for the first year. The luminous stems and see through appearance make it combine well with bolder textured plants. Regiar water in summer speeds growth and establishment the first year, in subsequent years it only requires irrigation once every two weeks. Freezes the ground at about 20ºF, returns quickly in spring when the soil warms. Not bothered by deer, not sure about rabbits. Excellent architectural plant. We took a break from growing this plant for years, we’re happy that its back.
Teucrium fruticans
Silver Germander is a wiry shrub with gray foliage and even lighter gray/white stems. All summer it bears pale blue small flowers with a prominent central lip. Traditionally used in topiary or as a trimmed hedge, it takes amazingly well to heavy shearing. It responds by becoming incredibly dense. Its malleability leads people to also trim it into any whimsical shape they can dream of. Full sun, average, well drained soil. Little to light summer water when established. Requires full sun and a hot position with protection from subfreezing wind. Classic mediterranean shrub. Grows as well at the cool coast as it does in the hot inland areas. To 4′ x 4′ if left unpruned.