February 2016 Plant Profile: Taiwania cryptomerioides

January 29th, 2016 by UWBG Communication Staff

By Ray Larson, Curator

Coffin tree branchesWhile there is an abundance of early blooms, bright bark and fragrance elsewhere in the Arboretum this time of year (particularly in the Winter Garden and Camellia Collection), winter is also a time to appreciate conifers.  One of the best and most unusual for foliar effects in February is Taiwania cryptomerioides, the Coffin tree.  We have three accessions totaling 8 trees in the Arboretum.  There are two from 1969 (Accession #315-69 A&B), four from 1996 (Accession #119-96 A-D) and two in the old nursery from 1974 (Accession #465-74 B&C).  The 1969 accessions are just south of the main Sequoiadendron grove just off Arboretum Drive E, and the 1996 plantings are at the Newton Street entrance in the Pinetum.  Using the interactive map on our website is a great way to easily locate plants.

From a distance Taiwania cryptomerioides looks a little in habit like a young western red cedar or false cypress.  But closer in its visual affinity to Cryptomeria becomes more apparent, hence the specific epithet meaning “resembling a Cryptomeria,” or Japanese cedar.  The Coffin tree is the only species in the genus Taiwania and hence is known as a monotypic genus.  The common name comes from the practice of some native peoples in its natural range using the trees for making coffins.  A tree is chosen at birth to be carved into a person’s coffin in old age.   The grove in the Pinetum is part of the ½ mile long interpretive trail, and selected specimens along the route feature information about the tree and its uses in small interpretive panels.

Coffin tree grouping

In older forests, trees with trunks up to 10 feet wide are not uncommon.  However the species is listed as Vulnerable to extensive logging in its native range.  Populations 500 years ago were much more robust and widespread.  The species is long-lived, and some older populations in Taiwan are now protected.

Ornamentally the tree has much to offer.  Perhaps most striking is the array of blue-green needles along the somewhat drooping branches.  They look sharp and stiff, but are surprisingly soft and flexible.  The textural effect is outstanding, and the narrow shape accentuates the somewhat weeping effect.  It is most attractive throughout the winter and spring seasons, and new growth is a brighter blue.  Like many conifers, older foliage does turn a brownish yellow before dropping, and this is usually most noticeable in late summer and early fall.  It does best in full sun.  In its native lands, it grows in mid to upper elevations in areas of summer and autumn rainfall but drier winters.  Despite this, it seems to do very well for us with our dry summers and wet winters.

Coffin tree needles

Next time you are in the Pinetum or near the giant Sequoias along Arboretum Drive, be sure to look for this species.  The ones at the Newton Street entrance are probably easiest to find, and if you haven’t been to this minor entrance from the Montlake Neighborhood, you’ll notice is reached from a quiet street end.

Common name:  Coffin tree
Family:  Cupressaceae
Location:  Grids 19-4E in the Sequoiadendron section, Grids 33-7E and 34-7E in the Pinetum at the Newton Street entrance
Origin:  Taiwan, northern Vietnam, Myanmar (Burma) and Yunnan, China.  Populations elsewhere in south-central China are believed to have been introduced.
Height and spread:  A large tree, that can reach over 200 feet in the wild.  It is fairly narrow in youth, and in cultivation is slower growing.  Considered the largest tree native to Asia
Hardiness:  Cold hardy to USDA Zone 8

Coffin tree with sign

December 2015 Plant Profile: Euonymus europaeus ‘Atrorubens’

November 26th, 2015 by Catherine Nelson, Adult Tours Program Assistant

euonymuseuropaensatrorubenseuonymuseuropaeus

Found in its native Europe, Euonymus europaeus ‘Atrorubens’, or spindle tree, is commonly seen as an understory shrub or small tree growing along deciduous woodland edges. Quite shade tolerant, it loves calcareous, well-drained base-rich soils and can grow up to 20’ tall. It is considered cold and drought tolerant. While labeled as invasive in some areas of the Northeast, it seems to behave itself here in the Pacific Northwest; the specimens in our collection have been here since the late 1940s and maintain their size at about 10’ x 6’. The easiest specimens to locate in the Washington Park Arboretum are in the Pinetum, tucked in between the cedars and the Coulter pines. You can’t miss them this time of year.

Traditionally, this plant’s stems were used to make spindles to twine wool and flax into yarn. It contains many medicinal properties in its roots and bark which were used by both Europeans and the Iroquois in Northeast America and Canada, where it spread widely after introduction to the new continent. While the fruits are eaten by a variety of animals in the plant’s native habitats, they are poisonous to humans.

The spindle tree is currently used as an ornamental garden feature, and the cultivar ‘Red Cascade’ has won the Royal Horticultural Society’s Award of Garden Merit. While its late spring flowers (small yellow cymes) are considered inconspicuous, its amazing orange fruits and pink sepals are brilliant in the fall and will persist into deep winter on the shrub. The ‘Atrorubens’ cultivar is prized for its bright red fall foliage, similar to its cousin the “burning bush” euonymus.

Common Name: Spindle Tree

Family: Celastraceae

Family Common Name: Bittersweet Family

Locations:
Washington Park Arboretum

  • Pinetum (555-42*B & D in 38-5W)
  • Pacific Connections Garden (555-42*A in 6-1E)

Origin: Northern Europe and UK

Height and Spread: to 20’ tall x 10’ wide

Bloom Time: late spring

November 2015 Plant Profile: Danae racemosa

November 3rd, 2015 by UWBG Communication Staff

By Roy Farrow

Danae racemosa photoNovember, I’ve found, is a difficult month to choose a garden highlight. The glory of autumn color is passing as the storms of our historically wettest month remove the most stubborn holdouts from the branches of our Acer, Stewartia, Oxydendrum and Fothergilla. Those same storms presage the return of honest-to-goodness mud, while the uplifting gems of winter such as Helleborus, Galanthus, Cyclamen and Hamamelis are still just distant dreams. Most people of sound mind are driven inside at this time for a much deserved break from the garden.

However, it is just these conditions that can spotlight the rare jewel for people still out and about. Danae racemosa is just such a jewel. During the summer months, its only request is that you keep it out of full sun. In the right shade, Poet’s Laurel is a fine, arching, bamboo-like mass of lush green foliage all year. Take a closer peak at the “foliage” and you might notice something odd. The leaves are actually just flattened stems called phylloclades. Danae spreads slowly by rhizomes.

A monotypic genus, Danae has but the one species. Currently listed in the family Asparagaceae, it has previously been located within Ruscaceae and even Liliaceae. Danae is closely related to Ruscus which also uses phylloclades rather than leaves, though Danae has terminal racemes of 1/8 in. flowers rather than have the flowers and fruit magically appear in the center of the “leaf” as with Ruscus. While the foliage of both Danae and Ruscus is quite long lasting even when cut, the fruit set of bright orange-to-red berries of Danae tends to be much more impressive than Ruscus, mostly because Ruscus requires both a male and female plant to be present, while Danae does not.

Come visit the Witt Winter Garden and you will see Danae racemosa growing in close proximity to both Ruscus hypoglossum and Ruscus aculeatus.

Name: Danae racemosa

Family: Asparagaceae (prev. Ruscaceae, Liliaceae)

Common Name: Alexandrian Laurel, Poet’s Laurel

Location: Witt Winter Garden, Washington Park Arboretum

Origin: Turkey, Iran

Height and Spread: 3’x4’

Danae racemosa with berries

Danae racemosa in the garden

October 2015 Plant Profile: Cucurbita maxima

September 29th, 2015 by UWBG Communication Staff

squash photoBy Sarah Geurink

Beautiful, packed with calories and vitamins, and easily stored for up to several months, winter squash is one of the most rewarding crops for vegetable gardeners to grow. One of our favorite squash varieties grown at the UW Student Farm at the Center for Urban Horticulture is Confection Squash. Similar to Crown Prince, popular in England, New Zealand, and Australia, Confection is a beautiful blue-grey, squat kabocha-type squash most notable for its incredible flavor, rich sweetness and texture, and edible skin. Confection squash is versatile, too—a perfect ingredient for savory soups or sweet pies alike. Note that Confection squash actually becomes more flavorful the longer it is stored, and will usually sit happily in storage throughout the winter. It is worth the wait!

Winter squash seeds should be sown in the spring, after your last spring frost and not less than 14 weeks before your first fall frost. Grow your winter squashes in a sunny area with fertile, well-drained soil with a pH between 6 and 6.5, and water your plants regularly. Confection squash is ripe when the fruit has taken on a blue-grey color, the stem has browned a bit, and the skin cannot be easily pierced with your fingernail. Expect to harvest 3-4 Confection squash fruits per plant.

 

Family: Cucurbitaceae
Genus: Cucurbita
species: C. maxima
Common Name: Confection Squash
Location: UW Student farm at the Center for Urban Horticulture

September 2015 Plant Profile: Acer japonicum ‘Aconitifolium’

September 8th, 2015 by UWBG Communication Staff

By Ray Larson, Curator

maple photoIn honor of the annual Elisabeth Miller Memorial Lecture on September 10 in Meany Hall, this month’s plant profile features one of her favorite trees, and perhaps the plant most associated with her:  Acer japonicum ‘Aconitifolium.’

At the UW Botanic Gardens, we have a grove of 6 planted in the Dorothy McVay Courtyard.  These trees were included at Mrs. Miller’s suggestion when Iain Robertson developed the garden design for the courtyard in the mid-1980s.  Betty Miller’s famous garden just north of Seattle includes over two dozen of the trees, which are among the very best small trees for texture and outstanding fall color.

They begin coloring in late July and slowly build to a crescendo of fiery reds ranging from flame orange to deep maroon.  They are among the most reliable trees for fall color in the Pacific Northwest, and generally at their peak in mid-October.
maple photo

As an added benefit they have small but showy flowers, which appear in early spring right before the leaves unfurl.  The shape of the leaves gives the tree its common name, and the scientific name refers to their resemblance to monkshood foliage (Aconitum).   They grow well in part shade to sun, with longest and best fall color appearing in more sun.  One of the best small trees for urban gardens, either singly or in a grove.  This is the most commonly grown Acer japonicum, but the UW Botanic Gardens has several other varieties, including impressive specimens of A. japonicum ‘O-isami’ and A. japonicum ‘Takinogawa’ in the Woodland Garden.  Acer japonicum ‘Aconitifolium’ received an Award of Garden Merit (AGM) from the Royal Horticultural Society in 1984.  It is reputedly hardier than other forms of Acer japonicum, and is rated down to USDA Zone 5.

maple leaf photoCommon name:  Fernleaf fullmoon maple
Family:   Sapindaceae
Location:  McVay Courtyard at the Center for Urban Horticulture
Origin:  The species is native to mountain forests of Japan, Manchuria and Korea.  According to Arthur Lee Jacobson’s North American Landscape Trees, this form was introduced to cultivation around 1888 by Parsons Nursery in Flushing, NY.
Height and spread:  Generally 12-18’ high and as wide
Bloom time:  Late March-early April
Bloom color:  dark red, and showy for a maple

McVay maples photo

August Plant Profile – Lagerstroemia indica x fauriei ‘Sioux’

August 6th, 2015 by UWBG Horticulturist

 

BloomIf this year’s hot and dry summer is a climate change omen for Seattle and the greater PNW, then here’s the tree of our future: Lagerstroemia spp and its many hybrids and cultivars. Commonly known as crapemyrtles, these trees are tolerant of hot and dry summers and offer appeal throughout the seasons. They have lustrous foliage and large colorful flowers in the growing season (spring and summer); in the dormant season (fall and winter), the foliage and bark provide interest.

‘Sioux’ is a National Arboretum Fauriei Hybrid crapemyrtle introduction from the 1950s that produces an abundance of large, bright pink flower clusters  during summer. Its foliage is the darkest green of any crapemyrtle and turns to a handsome purple color in fall. The bark is tan in color and the twigs have a reddish color. See National Arboretum link below for more information on the Fauriei hybrids.

http://www.usna.usda.gov/PhotoGallery/CrapemyrtleGallery/index.html

Common Name: Sioux Crape Myrtle

Location: Center for Urban Horticulture, west end of Douglas Greenhouse parking lot

Origin: National Arboretum Introduction. Name registered May 1, 1992.

Height and Spread: 12′-15′ tall; 8′-10′ wide. Multi-stemmed small tree, large shrub

Bloom Time: Summer, extended out as long as temperatures remain warm.

Specimen at CUH

Specimen at CUH

 

 

 

 

 

Plant Profile: Stewartia monadelpha

June 5th, 2015 by Jessica Farmer, Adult Education Supervisor

This small tree, commonly grown for its stunning reddish-brown bark, offers exceptional features throughout the year. Stewartia monadelpha, otherwise known as tall stewartia or orangebark stewartia, is just getting ready to come into bloom this month. Its white camellia-like flowers burst forth in early summer, followed by interesting brown seed pods and rich russet fall color. This species is planted in UW Botanic Gardens’ collections at both the Washington Park Arboretum and Center for Urban Horticulture.

Stewartia monadelpha is a member of the Camellia family. The small, white cup-shaped flowers last up to four weeks and have petals with smooth edges. This tree is best grown in partial shade but can handle full sun in the Pacific Northwest. It makes an excellent specimen tree for the home landscape.

Common Name: Tall Stewartia or Orangebark Stewartia
Location: Washington Park Arboretum: Camellia collection, Winter Garden; Center for Urban Horticulture: Event Lawn
Origin: Japan
Height and Spread: 20-25’ tall, 15-25’ wide
Bloom Time: June

Summer blooms of Stewartia monadelpha

Summer blooms of Stewartia monadelpha

Exfoliating bark of Stewartia monadelpha

Exfoliating bark of Stewartia monadelpha

Stewartia monadelpha fall color

Stewartia monadelpha fall color

Stewartia monadelpha in winter

Stewartia monadelpha in winter

May 2015 Plant Profile: Paeonia suffruticosa subsp. rockii

May 6th, 2015 by Soest Gardener, Riz Reyes

IMG_0069The peony has been a staple in gardens for hundreds of years and the UW Botanic Gardens has a wonderful representation of the genus this month at both the Washington Park Arboretum (WPA) and the Center for Urban Horticulture (CUH).

This month we are highlighting a spectacular peony that’s currently in bloom in the Pacific Connections Entry Gateway. Visitors stopped in their tracks by the large, dinner plate-sized blooms  which emit a wonderful scent. This is a pink form of the typically white flowered P. rockii. Found in Northwest China in Gansu Province. This species is characterized by a deep purple pattern in the center of each petal.

This type of peony is referred to as a “Tree Peony” by most gardeners. Although it’s not technically a tree, it is a woody shrub that does not die back and should not be cut down in the autumn like the more common bush peonies many people know. But like the bush form, it takes a few years before the plant is established and starts blooming well.

Both types are generally planted in the fall, but potted plants can be purchased and planted just about any time of year (except when the ground is frozen).

 

IMG_0071
Family: PAEONIACEAE
Genus species: Paeonia suffruticosa subsp. rockii
Common Name: Rock’s Peony, Joseph Rock Peony, Ziban Mudan
Location: WPA – Pacific Connections – China Entry Garden
Origin: NW China, Gansu Province
Height and Spread: 5-7′ height x 6′ width spread on mature, undisturbed plantings
Bloom/Fruit Time: April-May

 

April 2015 Plant Profile: Anemone nemorosa ‘Viridiflora’

March 23rd, 2015 by Soest Gardener, Riz Reyes

Anemone nemorosa 'Viridiflora' Wood Anemones are wonderful, easy to grow, spring ephemerals that require patience to get established, but once they get going, they form wonderful clumps in moist woodland conditions. What makes them sought after by gardeners is their ability to thrive in dry shade underneath mature trees. They have delicate fern-like foliage which set off the drifts of flowers that light up the spring landscape!

A. nemorosa flowers come in shades of blue, white, pink, with singles, doubles, and this most unusual form. This species has a remarkable tendency to mutate and the cultivar selection ‘Viridiflora’ (“green flower”) is a great example! What typically would be petals are actually modified leaves know as bracts. This creates an unusual moss-like texture and it’s absolutely charming combined with all the other plants in the garden as they burst into growth in spring. As with all wood anemones, they will begin to naturally die down in late spring and will rest until the following spring so be sure to mark where they are planted.

Anemone nemorosa 'Viridiflora'

Family: RANUNCULACEAE
Genus species ‘Cultivar’: Anemone nemorosa ‘Viridiflora’
Common Name: Green flowered Wood Anemone
Location: CUH Soest Garden – Bed 7
Origin: Native to Europe, but selection may be of Garden Origin
Height and Spread: 4-5″ height x 24″ width spread on mature, undisturbed plantings
Bloom/Fruit Time: March-April

 

March 2015 Plant Profile: Arctostaphylos densiflora ‘Sentinel’

March 3rd, 2015 by Soest Gardener, Riz Reyes

Arctostaphylos 'Sentinel'The manzanita is one of the most iconic of all West Coast native trees and shrubs, yet they are rarely ever seen in gardens. Like their famous relative, Arbutus menziesii (The Pacific Madrone), they’ve earned a reputation of being slow and difficult to establish. But with a strong emphasis in introducing more of our native flora into our gardens and the constant demand for drought tolerant plantings, the wide range of Manzanita species and hybrids have really started to come to the fore and gardeners are rediscovering their unique and stately presence in the landscape.

We have several specimens slowly getting established the Center for Urban Horticulture’s McVay Courtyard and one of the standouts is A. densiflora ‘Sentinel’. An upright grower discovered in Sonoma County, CA, it is one of the faster growing selections and it is also one of the most adaptable of the genus. The clusters of pink-to-white, urn-shaped flowers appear in later winter into spring like many in the genus, but the year round attraction is the evergreen foliage and the smooth and dramatic trunks with the often peeling, russet red bark. The older the specimen, the better they become.

Manzanitas require full open sun and very well drained soil that’s relatively lean. Avoid adding too much organic material to your soil and though they are drought tolerant, regular irrigation and fertilizer the first 2-3 years will get them going. They highly resent heavy root disturbance so take care when planting and avoid having to transplant it once its established in the ground. Staking of younger plants during planting is beneficial until they fully root in and settle.

 

Family: ERICACEAE
Genus species ‘Cultivar’: Arctostaphylos densiflora ‘Sentinel’
Common Name: Sentinel Manzanita
Location: McVay Courtyard – CUH
Origin: CA, USA
Height and Spread: 4-6′ height x 6′ wide
Bloom/Fruit Time: Late February-March