Threadleaf Bluestar is a fantastic native North American perennial with many seasons of interest. To 4′ tall this strongly clump-forming perennial has thread-like green leaves that line the sturdy, very vertical stems. Upon rising in late spring they host clusters of star shaped, fragrant (yep) blue flowers. Very pretty. The green, fine-textured foliage holds space as a blowsy presence in borders, gravel gardens, hellstrips. In autumn the entire plant turns shocking yellow and stays that way for weeks. Fall color at ground level and it rocks. Light but consistent summer water to aid in establishment. Very drought tolerant then. Full sun in any soil type but for permanently boggy. Good deer resistance. They will try it once but not again- for what it’s worth. Completely deciduous in winter. Emerges mid-spring. Very long lived, no-fuss perennial. Mix with ornamental grasses, cacti, just about anything.
Family: Apocynaceae
Apocynum androsaemifolium
Spreading Dogbane is a pretty semi-shrubby native perennial that is found in every biome in our area. David Douglas mentioned this billowing perennial with clouds of light pink/white bells. Mostly he hated tripping over it in the Willamette Valley. This very permanent plant spreads to form big drifts in the wild. Streambanks, prairies, alpine meadows it can appear. The rounded downward pointing leaves emerge on semi-woody stems. In June-August clouds of flowers appear for weeks. Loved by pollinators and birds specifically attractive to native hummingbirds and butterflies. To 2′ tall and spreading by stolons to a wide area. Water to establish then none in subsequent years. Mulch after planting. Virtually any somewhat rich soil type including amended sand. Full sun to part shade. Wonderful plant and floral texture for meadows. I have great childhood memories of this plant in July in full bloom perched with our huge native black bumble bees. Very convenient bloom time- it begins to bloom just as most other natives are finished. Dogbane is toxic when consumed by humans or animals- hence the common name. When stems are broken a milky sap is exuded. Moderate deer resistance. Distantly related to milkweed. Once very common in the Willamette Valley its territory has shrunk. Great performance in hellstrips and verges that are lightly or completely non-irrigated. Give this plant room to spread and plan ahead. Limited availability. Oregon native plant
Mandevilla laxa
Chilean Jasmine is not common in our region but it has been grown for many decades and it does well in warmer gardens, protected places. Large entire deep green leaves are 3″ long and opposite on twining stems. This strongly growing vine requires heavy and reliable support (See #4 copper wire). Blooms on new growth, which is continuous, In rich soil it can achieve 15′ in a season. The 2″ long tubular white flowers have the familiar propeller petal configuration of this family the Apocynaceae . The fragrance to me is delicious on warm days and nights and close to the blossoms which appear in clusters. It is not a sweetly cloying scent but more sophisticated. I once had this vine around my front door. In full bloom on warm summer nights it would be a cloud of perfume. Deciduous and often freezes back either 1/2- 3/4 of the way in colder than normal winters. In horrendous winters (below 12ºF) it can freeze away. Choose a protected site in full sun with rich soil and ample water. The more verdant the growth the more profuse the display and fragrance. Blooms late May- October. Avoid, cold frosty sites, cold gardens. In rural areas place it against south facing wall. Because it blooms on new wood and grows so prolifically it may be cut nearly to the ground for a fresh start to the year- do this in late March. In most summers large two chamber connected bean pods are 8″ long and bright green. When they ripen to tan they will twist and release downy clad black seeds that sail on the wind. Several winters in a row and the seeds that germinate may survive. I almost always lose them but the climate is changing and don’t bet on self sowing any way -its rare Root hardy to about 5ºF- mulch for added protection. Exquisite vine. Native to central southern Chile.
Nerium oleander ‘Hardy Pink’
This is a relatively hardy selection of Oleander with profuse pale pink flowers at the end of summer. Not quite as cold hardy as ‘Hardy Red’- ‘Hardy Pink’ will show foliage damage at about 16ºF. Therefore, it should be placed in the most protected sites as possible. A south or west facing wall is ideal. Not recommended for gardens outside of the urban heat island – the city of Portland. To 5′ x 5′ and recovering quickly in spring if frozen over winter. Blooms from deep pink buds open to paler pink in August to September. High deer resistance. Thrives in the hottest sites possible.
Nerium oleander ‘Hardy Red’
Surprisingly hardy Oleander that is perfectly at home in warmer gardens. Upright then arching evergreen shrub to 5′ x 5′ in 6 years. In June to September a continuous supply of trusses of bright cherry red (hot pink) flowers. Very showy and welcome in summer. Foliage is hardy to approximately 12ºF and will be damaged below that. Recovery is very rapid and bloom will still commence. Prune before flowering if needed. Full, HOT sun in a protected location. Best against a south or west facing wall- out of subfreezing east wind. Light summer water when established. As our experiments have revealed this is a showy, hardy shrub. The hardiest we’ve grown and the best flowering.
Nerium oleander ‘Mathilde Ferrier’
Who would have guessed that one of the hardiest Oleanders would be a double flowering light yellow? Not me, but here she is and yes she is hardy in the city of Portland. Tall growing vigorous evergreen shrub to 8′ x 4′ in 5 years. In summer clusters of FRAGRANT double soft yellow flowers are profuse and sincerely beautiful. It blooms off and on until September. Full hot sun in a protected location- against a south or west facing wall is ideal. Injured by cold at about 13ºF and below but it recovers remarkably fast in spring when truly warm weather arrives and it will still bloom (blooms on new wood). It really is a pretty flowering shrub for a protected spot. The more heat it gets in summer the hardier to cold in the winter. Makes sense.
Rhazya orientalis
Asian Blue Star is so closely related to our American native Amsonias that many believe it should be in the same genus. Tough, elegant, cool perennial that rises to 2′ tall and is topped by clusters of NAVY BLUE starts in late spring. Bring on the bumblebees. Forms a slowly increasing clump in rich to average soil with regular summer water. Though established plants can easily handle drought. In autumn the whole plant turns from green to bright yellow and holds that color for an extended time. Very showy. Long lived, hardy perennial for full sun. No pests or disease. Winter deciduous.
Trachelospermum ‘Ogon’
A cute gold leaved form of asian star jasmine that makes a dainty evergreen vine for a trellis or arbor. Dense layered foliage is bright gold/chartruese and is best with some protection from hot afternoon sun. This is a slower growing Star Jasmine with a smaller dimension over all. This makes it a great candidate for smaller trelliage that you don’t want to obscure or cover entirely. Bone colored lightly fragrant flowers occasionally occur in late spring on wood from the previous season. To 9′ tall and 3′ wide in 7 years. Rich, well drained soil with regular summer water. Part shade to shade or an open north exposure. May be self clinging in wind free situations. Very good cold hardiness and drought tolerant when established. Valuable little vine for shade. Lights up dark corners and even makes a handsome ground cover.
Trachelospermum asiaticum ‘Chirofu Chirimen’
Cool little Asian Star Jasmine with tiny variegated leaves that forms dense mounds as a ground cover or in time it can reach up as a cute and not strangling vine. Each leaf is margined and splashed with white. New growth has distinct pink tints for a distinct multicolor effect. Forms a fine textured plant but as a small scale ground cover it will block weeds. To 1′ tall x 30″ wide as a ground cover. To 8′ tall or higher as a self clinging vine in wind free places. Rich, well drained soil with regular summer water. Definitely double dig the soil before planting to incorporate oxygen as well as assist in absorption of water. Add organic fertilizer as well. Trachelospermums appreciate good drainage and regular summer irrigation to do their best. Otherwise drought tolerant but slow growing. Nice on fences or screens or up the trunk of a Trachycarpus (Windmill Palm). Good deer resistance. Evergreen.
Trachelospermum asiaticum ‘Ogon Nishiki’
This poor plant though spectacular has a bunch of silly marketing names attached to it. We stick with the original Japanese cultivar name- seems appropriate. No other evergreen vine/groundcover has a foliage display that matches this plant. New leaves emerge bright orange and then morph slowly to patches of light yellow surrounded by dark green. Delightful. We’ve never seen flowers on this cultivar and we don’t need to. Great small scale and vivid ground cover. Mounds and trails to 8″ tall and several feet wide in a single season. It has been surprisingly hardy to cold enduring temps below 10ºF with no harm. Best in part shade to shade in rich, well drained soil with regular summer water. This vine grows when its warm therefore you water it when its warm. Twins around thin objects and will eventually hoist itself skyward. Solidly evergreen. Excellent container plant. Moderate deer resistance.