Inside-Out-Flower is a commonly seen terrestrial component in dry to moderately moist woodlands in our region. The duck foot shaped leaves are conspicuous and pretty and in late spring to mid-summer a continuous supply of dainty downward pointing white flowers. Spreads in gardens very well in enriched soil with regular summer water where it will quickly assume the role of an intertwining ground cover. Winter deciduous- un-like its close and much more drought adapted relative Vancouveria chrysantha (Yellow inside-out-flower, Siskiyou Vancouveria). This perennial is perfect for life among shrubs or mixing with other woodland perennials in part shade to shade. Adapts well to garden culture and thrives on regular summer irrigation. Locally native in the city of Portland. To 10″ tall and spreading. Some deer resistance. Oregon native plant.
Biome: Dry Shade
Dry shade offers a particular challenge to PNW gardeners. In fact, it can be the hardest location to satisfactorily grow plants. Many gardeners have dry shade, a tall canopy of Douglas Fir or Oregon White Oak or even neighborhood street trees that can conspire to rob plants not only of light but water as well. And to complicate matters, the more you irrigate dry shade near trees the more tree roots you get and the more competition for your lovelies. The solution is to depend on plants that have these three adaptations: dry tolerance, root competition, low light conditions.
We’ve amassed a list of plants that really will thrive in these conditions. A good deal of these plants are native to the forest understory in Asia, they are built for serious competition with Bamboo. Many of our very best dry shade plants are from the Pacific Northwest and already inhabit dry woods. Invite these plants into your garden, they play an important role.
Prepare the soil as you would any rich perennial border. Add and incorporate compost and mulch. Give each plant a handful of all organic fertilizer to speed root growth and establishment and water faithfully for the first season. In these conditions an annual application of mulch is not obscene and will reap great rewards. In time you can water much more infrequently.
Climate Adapted Plants for Gardeners in the PNW
Viburnum ellipticum
Oregon Viburnum or Western Way Faring tree is a moderate to large native deciduous shrub. It stretches a little bit into W. Washington where it is rare but its primary populations are in western Oregon and south into N. California. Its found in moist to dry woods often on the margin where its can get at least half a day sun. It also thrives only much larger and lankier in outline in the shade. It easily tolerates winter inundation but is found on well developed soils in upland situations as well. Its common associates in the wild are Oregon white oak/Quercus garryana, Oregon Ash/Fraxinus latifolius, Cornus stolonifera. Leaves are round, glossy and scalloped and are very handsome on a well proportioned fountain shaped shrub. Shorter in full sun, taller in shade. This plant needs just a modicum of light watering for its first year and once it is thoroughly established you can set it free. In late spring off white cymes of flowers have the fragrance to me of raw potatoes. We had a large specimen of this shrub in our back 40 where I grew up near Eugene. In certain years it can produce quite a fall show with orange/red tinted leaves and translucent blue fruits. Blooms on wood from the previous year. Prune if needed AFTER blooming has ended. June. To 5′ tall in the sun to much taller in shade. Protect young plants from deer. Oregon native plant.
Viburnum japonicum ‘Variegatum’
Unusual and actually superior form of this species with large glossy evergreen leaves splashed with yellow. In spring flat corymbs of flowers appear and remind me of lace. Red berries follow but are consumed by birds. This form is not prone to mildew which can afflict the green leaved form. So, we love it for it’s bold leaves that look good year round and easy demeanor. To 8′ x 8′ in 10 years. Full sun to quite a bit of shade. Doesn’t burn in sun. Adaptable. Light summer water once established. Very old specimens get by with no summer water. Excellent year round appearance. Take out green reversions if they occur. Blooms on wood from the previous season- prune if needed after flowering. Specimen. Nice shrub.
Spring bouquet viburnum or Laurusitinus is a common shrub in our climate. This form lightens up what can be a very pedestrian plant. The edges of the evergreen leaves are margined in cream with an interior of soft green. This makes a shrub that glows year round and can be used to lighten up dark corners. In autumn clusters of pink buds form and hold until mid winter. Then as the days begin to lengthen it opens these clusters which are lightly fragrant and white. Strong growing shrub that requires very little water once established. To 8′ tall and 5′ wide in 6 years. Full sun to part shade to high overhead shade. Nice looking, tough shrub native to the Mediterranean very easy to grow and long lived. If a green sport appears simply prune it off to the base to retain the variegated form. Water to establish. Not deer resistant. Excellent backdrop to a mixed border or trimmed into a contained hedge. Nice fast growing screen. Blue berries sometimes follow the flowers. Buds and flowers put on a show for months. Blooms on wood from the previous season prune after flowering if needed. Naturally dense and rounded.
Viburnum x burkwoodii ‘Anne Russell’
Really there is nothing like the clove/carnation/sweet fragrance of this shrub in late winter to early spring. The large clusters of flowers begin as pink buds and open to white. Nice bicolor effect along the way. Blooms 3-4 weeks. Evergreen to semi-evergreen to deciduous in arctic places. Large growing shrub that can attain tree like proportions with great age. To 8′ x 4′ in 7 years. Full sun to quite a bit of shade in rich to average well drained sites. Light consistent summer water speeds growth and increases spring flowering. Otherwise relatively drought adapted, especially in shade. Tolerate the most obnoxious sticky clay soils- especially on slopes. Plant where you can pass by the flowers and take a big ol whiff. Very easy to grow. Prune AFTER flowering.
Viola odorata (Parma) ‘Alba Plena’
This cool cultivar of Parma violet can be difficult to stumble upon. We love the plush double white flowers that sends its sweet perfume on the breeze in late winter to mid-spring. Parma violets are basically the Sicilian version of the common sweet violet (Viola odorata). They are not nearly as cold hardy or pernicious as the species and they tend to have much larger more opulent and fragrant flowers. Also, their leaves are distinctively glossy as opposed to matte. This little sweetie forms spreading patches and the long stems are a bit weak for the large double white flowers- they tend to bend. Excellent for small bouquets that you can sniff and sniff. In the garden they need a sheltered position away from the freeze and thaw and harsh conditions in the open. Instead coset them under large shrubs and among ephemeral early perennials such as Anemones, and small bulbs like species Crocus. Part shade- they bloom best with a bit of sun. Regular summer water encourages them to spread. This form seldom sets seed- I don’t think I’ve ever seen seed in fact. Pity. Rare plant.
Viola odorata (Parma) ‘Duchess du Parme’
There’s nothing like the smell of sweet violets in late winter and early spring. But the regular species in our climate is nothing less than a thug. It seeds and grows where you really would rather not have it. Well, forget that. Enter this exquisite fully double flowering Parma Violet. The rich violet blue flowers appear on long stems from January to April. Parma violets are the Mediterranean form of V. odorata and they are less hardy to cold and not so rampant. This form we have never seen set seed- but there are always exceptions. Very glossy green foliage frames the flowers well. Excellent in containers in an unheated greenhouse, conservatory. In the garden choose a protected spot (under evergreen shrubs for example) and give this violet rich soil with regular summer moisture. Tolerates full sun but looks better with some shade. Flowers tend to lean horizontally, they are great for cutting and making little fragrant winter posies. Spreads by runners to form a nice patch in time. Tolerates summer drought when established.
Whipplea modesta
Yerba de Selva or whipple vine, a wonderful small scale evergreen native ground cover. Related to Hydrangeas but this trailer is actually very droughtadapted.e In late spring clouds of small white flowers , Scrambling plant to about 8″ tall and 2′ wide. Full sun to considerable shade. From Portland south this is a common understory component of the herb field. It grew happily in our back 40 where I grew up. There it made pretty scrambling patches between Vancouveria, snow berry and hairy honeysuckle. Often you would see our native columbine ( Aquilegia formosa) as an associate. Its very drought adapted when established but it improves with a few soaks over summer- never perpetually wet and never hot and wet. Otherwise an easy native that should be grown a lot more. For use as a small scale ground cover plant on 10″ centers. It will also gracefully trail over rockeries and walls. Butterflies adore the flowers. Competes well with invasives. Some deer resistance. It may be cut back in early spring to refresh. Once native in the Portland city limits. This is a great native understory for Arctostaphylos, which is frequently seen in the wild. Oregon native plant.