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.
Spiraea splendens (densiflora)
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.
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 betulifolia var. lucida
Underused native Spiraea from the western United States and native in Oregon including the immediate Portland area. Low mounding deciduous shrub to 2′ x 3′. This is the locally native form. Often the straight species is for sale- its from Asia and is 4 times the size of ours. Pink buds open to foamy white flat clusters of flowers appear in late spring. In autumn it turns amazingly vivid colors of red/orange/gold and it holds its color for weeks. One of the most drought tolerant of the genus requiring light summer water to very little. Full sun and rich soil. Spreads to form patches. Locally native and plentiful near the Columbia Gorge and throughout the mountains whose diminutive habit means that pruning is seldom necessary. Blooms on wood from the previous season. Long lived and an excellent landscape shrub. Birch Leaf Spiraea or glossy leaved Spiraea. Native in the Portland city limits. Oregon native plant.