The Wonderful World of Monocots

June 7th, 2016 by UWBG Horticulturist

Monocotyledons, commonly referred to as monocots, are flowering plants whose seeds typically contain only one embryonic leaf, or cotyledon.  A quarter of the world’s known plants are monocots. They are the most economically important group of plants to humans today in agriculture, horticulture, forestry and fiber industries.  Here are a few samples of monocots in our plant collections.

Selected cuttings from the Washington Park Arboretum or Center for Urban Horticulture (June 1 - 12, 2016)

Selected cuttings from the Washington Park Arboretum or Center for Urban Horticulture (June 1 – 12, 2016)

1)  Allium schubertii                                                                            (Ornamental Tumbleweed Onion)

  • Dried seed heads look like starry tumbleweeds or shooting star fireworks
  • Located in the Soest Herbaceous Display Garden, bed 6 at the Center for Urban Horticulture

2)  Austroderia richardii syn Cortedaria r.                     (Toetoe Grass, Plumed Tussock Grass)

  • Ornamental grass native to New Zealand
  • This “pampas” grass seems to be behaving itself in the Pacific Northwest, unlike others that do seed around and could be considered invasive.

3)  Phormium colensoi                (Mountain Flax, Wharariki)

  • One of two species in the genus Phormium; both are endemic to New Zealand.
  • Fiber from its broad, sword-like leaves, can be made into Maori baskets.

4)  Phyllostachys nigra                 (Black Bamboo)

  • Native to China, but widely cultivated elsewhere
  • Known for its ornamental beauty and prized for decorative woodworking
Close-up photo of fruit from a Chinese Windmill Palm tree

Close-up photo of fruit from a Chinese Windmill Palm

5)  Trachycarpus fortunei                (Chinese Windmill Palm)

  • Only palm that is reliably hardy to the Puget Sound area
  • Dioecious, with male and female flowers produced on separate trees
  • Sample of mature fruit cluster and frond

To locate specimens of these plants, please visit our interactive map:
http://depts.washington.edu/uwbg/gardens/map.html.

Spring Pushes Forth at the Washington Park Arboretum

May 23rd, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum (May 16 - 30, 2016)

Selected cuttings from the Washington Park Arboretum
(May 16 – 30, 2016)

1)   Ostrya carpinifolia                Hop Hornbeam

  • This small-to-medium-sized tree (40-50’) is native to southern Europe and southwestern Asia.
  • The common name refers to the fruit which resembles the fruit of Humulus (Hops).
  • Ostrya is from Greek, meaning “bone-like” in reference to the trees dense hard wood.
  • Located north of East Foster Island Road, east of the Broadmoor entrance.

2)  Picea mariana ‘Doumetii’                Doumet Black Spruce

  • This selection of Picea mariana is a popular slow-growing shrub with blue green needles and a dense conical growth habit.
  • Located along Arboretum Drive on the north end of the Magnolia Collection.

3)  Pinus x schwerinii                Schwerin’s Pine

  • Schwerin’s Pine is an interspecies cross between Himalayan White Pine (Pinus wallichiana) and Weymouth Pine (Pinus strobus). It was found by Earl Schwerin in his park in Wilmersdorf (near Berlin, Germany) in 1905.
  • Our fine specimen is located north of the Crabapple Meadow near the service road.

4)  Pterocarya macroptera                Large–Winged Wingnut

  • Native to northern China, the Wingnut is a fast-growing, medium height tree to 50-70 feet tall and 40 feet wide.
  • This tree boasts ornamental spikes of fruit with broad wings in long pendulous spikes.
  • This tree can be seen in fruit east of Arboretum Drive and south of the Crabapple Meadow. Look for the long bright green chains before you reach the service road.

5)  Tillia cordata ‘Bicentennial’                Bicentennial Littleleaf Linden

  • This selection of the popular street tree is known for a dense and conical form.
  • Its moderate size makes Tillia cordata useful in areas where space is limited.
  • Littleleaf Linden is known for its sweetly-scented spring flowers. Tillia fruit are held below a stiff bract similar to that on a maple seed which acts like a “helicopter” as it falls.
  • A fine specimen can be seen at the intersection of Arboretum Drive and East Foster Island Road.

May Colors Appear Just in Time for Mother’s Day!

May 7th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum (May 2 - 15, 2016)

Selected cuttings from the Washington Park Arboretum
(May 2 – 15, 2016)

Happy Mother’s Day!

1)  Philadelphus coronarius

  • Native to southeastern Europe and Asia Minor, this shrub is located within the Sorbus Collection. It is perhaps the best-known species of mock orange in gardens because of its sweet smell. The fragrance of its flowers is pleasing out-of-doors, but may become too strong if the plants are numerous or near sitting room windows.
  • Philadelphus is a member of the plant family, Hydrangeaceae.

2)  Rhododendron   ‘Favor Major’

  • Located just west of parking lot #5, this hybrid is showing its yellowish-orange flowers.

3)  Rhododendron   ‘Ruby Hart’

  • Located within the Hybrid Bed, this shrub certainly has been given an appropriate cultivar name.

4)  Robinia x holdtii

  • A member of the plant family, Leguminosae, the genus Robinia contains about
    20 deciduous trees and shrubs confined to North America. The name Robinia
    commemorates Jean Robin, herbalist to Henry IV of France.
  • Specimen is located in the Legumes.

5)  Styrax obassia

  • A broadly columnar deciduous tree bearing elliptic dark green leaves and bell-
    shaped white flowers, S. obassia is native to northern China, Korea, and Japan.
  • This specimen is located along the upper trail near Rhododendron Glen.

“Story Time” at the Washington Park Arboretum

April 25th, 2016 by UWBG Horticulturist

The stories of people and plants are intricately intertwined.  The plants of the University of Washington Botanic Gardens have many stories to tell, and here are just a few to wet your whistle.  Explore our website at to look up and locate plants in the Arboretum and learn more of our stories.

Selected cuttings from the Washington Park Arboretum, April 18 - May 2, 2016

1)  Abies grandis – Grand Fir                “Fir Above It All”

  • This particular tree has witnessed the entire history of the Washington Park Arboretum.  It is almost certainly a remnant of the vegetation that existed before the site was logged circa 1896.  You can read more about this remarkable tree’s history on the March 2016 plant profile.

2)  Castenea dentata – American Chestnut
“A Blight to Remember”

  • Once upon a time in the eastern forests of North America, the mighty American Chestnut was a ubiquitous giant.  This tree could shape entire ecosystems, providing food and shelter to all manner of beasts and men.  It was said that the chestnuts would sometimes pile up so high you could scoop them up with a shovel.  This fast-growing timber tree provided wood that could be used to make almost anything a carpenter can build. Sadly, this tree has been decimated by “chestnut blight”, a fungus that quickly girdles and kills the tree.  The University of Washington Botanic Gardens is committed to the conservation of this tree and many other species that are threatened.

3)  Rhododendron ‘Lem’s Cameo’                “Halfdan Lem and the Rhodies of War”

  • Some of Halfdan Lem’s story was told to the Vancouver Rhododendron Society meeting of March 1993.  When World War II started, Mr. Fred Rose in England sent Lem seed and scions of many of his crosses and the resulting plants formed the nucleus of Lem’s breeding program.  By the mid-sixties, he had made over 2000 crosses and had about 50,000 seedlings.  One of his first introductions was “Lem’s Cameo”, an outstanding and popular variety.  Halfdan was reported to be quite a “colorful” character, and you can see some of his legacy in the Puget Sound Hybrid Garden.  Many other stories about Halfdan Lem may be found in the Journal of the American Rhododendron Society, which is available online.

April Color Appears at the Washington Park Arboretum

April 10th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum, April 4 - 17, 2016

Selected cuttings from the Washington Park Arboretum,
April 4 – 17, 2016

1)  Acer mandshuricum                Manchurian Maple

  • The Manchurian Maple is native from Eastern Siberia into China and strongly resembles Acer griseum and Acer triflorum.
  • This species is located in the Asian Maples Collection.

2)  Distylium racemosum                Isu Tree

  • The flowers of Distylium racemosum are petalless, but have attractive red calyces (whorl of sepals) and purple stamens.
  • The Isu tree is native to southern Japan, but can be found in the Witt Winter Garden and in our Hamamelidaceae Collection, east of Arboretum Drive near the Pacific Connections gardens.

3)  Pieris japonica                Lily-of-the-Valley Shrub

  • This shrub from eastern China, Taiwan and Japan begins the spring with showy terminal panicles of flowers that range from white to dark-red, followed by extremely colorful new growth which will fade to green in summertime.
  • Lily-of-the-Valley can be found at the Graham Visitor Center, the Witt Winter Garden and Rhododendron Glen.

4)  Rehderodendron macrocarpum

  • This native of southwestern China and Vietnam is a member of the Styracaceae family and displays typical Styracaceous white pendent flowers in Spring.
  • Though a relatively small tree in the Pacific Northwest, Rehderodendron macrocarpum is a dominant component in its native habitat.
  • Specimens can be found along Azalea Way near our Puget Sound Rhododendron hybridizers bed as well as in the Witt Winter and Woodland Gardens.

5)  Viburnum bitchuense                Bitchiu Viburnum

  • This native of Korea and Japan has pink buds that open to wonderfully fragrant white flowers.
  • Viburnum bitchiuense can be found just across Arboretum Drive, outside the east doors of the Graham Visitor Center.

A Subtle Side of Spring

March 28th, 2016 by UWBG Horticulturist

Spring is not typically known for its subtlety around these parts, but upon its early awakening many plants warrant a closer look. Enjoy!

Selected cuttings from the Washington Park Arboretum, March 21, 2016 - April 4, 2016

Selected cuttings from the Washington Park Arboretum,
March 21, 2016 – April 4, 2016

1)  Acer palmatum ‘Katsura’                     Katsura Maple

Close-up of Acer palmatum 'Katsura'

Close-up of Acer palmatum ‘Katsura’

  • One of the first Japanese maples to leaf out each spring. The small, five-lobed leaves emerge pale yellow-orange, with brighter orange margins.
  • Found in the semi-dwarf group of Japanese maples.
  • Specimen 19-10*A is located in grid 30-4E.

2)  Ginkgo biloba                     Maidenhair Tree

  • Emerging leaves are “mini-mes” of the actual size.
  • Also seen are emerging male cones.
  • This sample is taken from the Graham Visitor Center specimen located in the northwestern corner of the parking lot.

3)  Larix laricina                     Tamarack or Eastern Larch

  • Deciduous conifer native to eastern North America
  • Cutting sample shows newly emerging needles and last year’s cones.
  • Specimen is located in grid 33-5W, Pinetum.

4)  Photinia beauverdiana var. notabilis

  • Rose family deciduous shrub from China
  • Hairy, white newly-emerging leaves and flowers on cutting sample
  • Specimen is located in grid 33-5W, Pinetum.

5)  Ribes sp. (maybe R. menziesii)                     Gooseberry (maybe Canyon Gooseberry)

  • Though this Ribes sp. has not been positively ID’d, it is indeed a gooseberry because it has spines.
  • Not the eye-catching Ribes sanguineum flowers, but beautiful nevertheless.
  • Thicket is located behind the Stone Cottage.

February Color Appears at the Washington Park Arboretum (Part II)

February 29th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum (February 22, 2016 - March 7, 2016)

Selected cuttings from the Washington Park Arboretum
(February 22, 2016 – March 7, 2016)

1)  Chaenomeles cathayensis                   Chinese Quince

  • This deciduous shrub is native to slopes and forest margins in western Hubei Province.
  • Light pink flowers in spring are followed by large oblong fruit which are unpalatable raw, but make fragrant jams and jellies when cooked.
  • Like other quince, Chaenomeles cathayensis’ arching branches are armed with stiff thorns.
  • Two specimens can be seen in the old field nursery south of the Crab Apple Meadow near Arboretum Drive.

2)  Corylopsis glabrescens         Japanese Winter Hazel

  • A broadly-spreading deciduous shrub native to Korea and Japan, this plant is noted for its graceful habit and fragrant yellow flowers in late winter.
  • A relative of witch hazel, Corylopsis are a great way to extend the bloom time of the winter landscape.
  • Some beautiful specimens can be seen on the trail to Azalea Way, west of the Witt Winter Garden.

3)  Cryptomeria japonica  ‘Nana’                     Dwarf Japanese Cedar

  • Introduced to England from China by Robert Fortune in 1842, this slow-growing conifer is one of the earliest cultivars.
  • Our specimen, planted in 1960, is located north of the grove of Sequoia sempervirens in the Pinetum.

4)  Osmanthus x burkwoodii                      Hybrid Sweet Olive

  • A hybrid of Osmanthus delevayi and Osmanthus decorus, this large evergreen shrub boasts the beauty of the former with the toughness and adaptability of the latter.
  • Small tubular white flowers exude a powerful jasmine fragrance in spring.
  • Several specimens can be seen along Foster Island Drive near the entrance to the maintenance yard.

5)  Sequoia sempervirens  ‘Henderson’s Blue’                    Henderson’s Blue Coast Redwood

  • This vigorous, blue-gray needled tree is a cultivar of the species native to the central and northern California coast.
  • The species is in the family Taxodiaceae, which also includes Sequoiadendron giganteum and Taxodium distichum, two important North American natives.
  • Located north of the grove of Sequoia sempervirens in the Pinetum.

February Color Appears at the Washington Park Arboretum

February 14th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum, February 8 - 21, 2015

Selected cuttings from the Washington Park Arboretum,
February 8 – 21, 2015

1)  Pinus greggii

  • This three-needle pine from northeastern Mexico is closely akin to P. patula but less ornamental.  Its oval-conical cone clusters stay closed on the branch for several years.  This specimen and the others described here can be found within Crabapple Meadow, along the east side of Arboretum Drive.

2)  Pinus jeffreyi

  • Native mainly of California in the Sierra Nevada and Siskiyous, this lofty tree is said to grow to 200 feet in the wild.  P. jeffreyi is closely allied to P. ponderosa and at one time, it was normal to regard it as a variety of that species.  Its three-needle bundles are said to give off a fruity scent when bruised.
Close-up of cones from Pinus greggii

Close-up of Pinus greggii cones

3)  Pinus montezumae var. lindleyi

  • This five-needle pine is native to southern and central Mexico at subtropical and cool temperate altitudes, with its best development at 7,000 to 8,000 ft.  Its flexible, pendulous leaves (growing to 14 inches or longer) along with its broad, dome-shaped crown give it a distinct look.

4)  Pinus pinaster

  • Commonly known as the Maritime Pine, this specimen is native to southwestern Europe and north Africa.  The glossy green leaves of this pine are the largest and stoutest of all two-needle pines, and it is said to be one of the best for light sandy soils.  As its common name implies, it thrives in coastal maritime localities.

5)  Pinus strobus ‘Fastigiata’

  • A native of eastern North America, P. strobus has proven to be a valuable timber tree and one of the richest assets of our country.  Its bluish-green five-needle clusters are three to five inches long, with lines of white stomata on the inner sides.  Once again, all of these specimens listed here can be found within Crabapple Meadow, along the east side of Arboretum Drive.

Late January Color Appears at the Washington Park Arboretum

January 31st, 2016 by UWBG Horticulturist

Sleeping Beauties

Selected cuttings from the Washington Park Arboretum (January 25 - February 7, 2016)

Selected cuttings from the Washington Park Arboretum
(January 25 – February 7, 2016)

1)  Oemleria cerasiformis                Indian Plum

  • The Indian Plum adheres to Benjamin Franklin’s advice in Poor Richards Almanac: “Early to bed, early to rise. . . .”  This shrub goes to sleep early, beginning to slowly defoliate in late summer.  However, it is one of the first to leaf out, and flowers early in the spring.  It can be found throughout the Arboretum, and is just beginning to awaken.

2)  Ophiopogon planiscapus ‘Nigrescens’                          Black Mondo Grass

3)  Magnolia × soulangeana                Saucer Magnolia

  • The Saucer Magnolia wraps its flower buds in a fuzzy blanket for its winter nap.  As winter draws to a close and spring approaches, these buds will swell and open into a glorious pink and white show.  You can find this and many other specimens of this wonderful genus in our nationally-recognized Magnolia Collection (http://depts.washington.edu/uwbg/gardens/wpa/collections.php).

4)  Polystichum munitum                Western Sword Fern

  • The Western Sword Fern spends its winter in a tightly coiled bunch.  As they unfurl in spring, these are called fiddleheads, as they resemble the curled ornamentation (called a scroll) on the end of a stringed instrument, such as a violin.  Fiddleheads also just happens to be the name of the UW Botanic Gardens’ Nature Preschool Program (http://depts.washington.edu/uwbg/education/Youth/nature_preschool.shtml).

5)  Tsuga heterophylla                Western Hemlock

  • Not all the plants in the Arboretum are providing shade for Little Nemo in Slumberland.  Some plants, such as conifers like the Western Hemlock, do not go to sleep during the winter.  As long as it is not too cold, they will happily photosynthesize, converting water and air into sugar.

January Color Brings in the New Year at the Washington Park Arboretum

January 16th, 2016 by UWBG Horticulturist
Selected cuttings from the Witt Winter Garden at the Washington Park Arboretum (January 11-24, 2016)

Selected cuttings from the Witt Winter Garden at the Washington Park Arboretum (January 11-24, 2016)

Witt Winter Garden

1)  Cornus sanguinea ‘Midwinter Fire’
Midwinter Fire Dogwood

  • Though the species normally has red twigs and purple fall color, this outstanding cultivar has golden-yellow fall color followed by red-blushed, yellow twigs.
  • This dogwood is native to northern Europe into northwestern Asia.
  • Full sun is required to obtain the best winter stem color and this dogwood will slowly colonize an area via suckers from its shallow roots unless controlled.

2)  Corylus maxima  ‘Atropurpurea Superba’                Purple Giant Filbert

  • This excellent selection of the Giant Filbert produces long purple catkins in winter followed by large purple-red leaves in spring.
  • From what we have observed in the Witt Winter Garden, this specimen is resistant to eastern filbert twig blight, caused by the fungus Anisogramma anomala.

3)  Daphne bholua  ‘Jacqueline Postill’                Lokta, Paper Daphne

  • The specific epithet “bholua” comes from “bhulu swa”, the Nepalese name for the species.
  • Despite having a native range to 12,000 feet in the Himalayas, this species of Daphne is just as hardy in Seattle and requires a protected placement in the garden.

4)  Hamamelis x intermedia  ‘Winter Beauty’                Winter Beauty Witch Hazel

  • The north end of the Witt Winter Garden contains many species and cultivars of witch hazel.
  • Witch hazel flowers range from sulfur-yellow to carmine-red, while their fragrance can be absent, lightly floral or an intense citrus.

5)  Sarcococca hookeriana var. digyna                Sweet Box

  • Sweet box is an often overlooked element of the Witt Winter Garden due to the diminutive size of its flowers, though no one can miss their intense fragrance.
  • Perfectly comfortable in dry shade, Sweet Box is an excellent choice for under-planting taller shrubs or small trees such as Hamamelis.