November 26th, 2015 by Catherine Nelson, Adult Tours Program Assistant
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 Common Name: Bittersweet Family
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
September 11th, 2015 by Catherine Nelson, Adult Tours Program Assistant
Pterocarya stenoptera, common name Chinese Wing Nut, has gorgeous lime green seed catkins 12-14″ long each bearing up to 80 seeds. That’s pretty amazing in itself but when these seed catkins are dripping off of each limb of a tall tree the effect is stunning.
The Wing Nut genus resides in the walnut family, or Juglandaceae, and is used for ornamental purposes in gardens around the world. Its native habitats are in China, Japan, and Korea, growing in areas from sea level to elevations of about 1500 feet. Like its cousin nut trees – the Walnut, Pecan & Hickory – this large deciduous tree has pinnate leaves and grows quickly with a rangy habit.
We have a few different Pterocarya species in the Washington Park Arboretum collection. I like to stop and admire the large P. stenoptera specimen along Azalea Way; it was acquired in 1951 and is now about 60′ feet tall. Because it has many low-hanging limbs, you can touch the seed catkins, which are surprisingly rigid and tough.
You can learn about this tree and many others in our collection if you join our Free Weekend Walks for September. Our tour theme is “Fruits, Nuts & Seed Pods” because right now is the time to marvel at the bounty which is the result of spring pollination. Guides meet visitors at the Graham Visitors Center every Sunday at 1:00 pm and off you go to explore our great park.
July 16th, 2015 by Catherine Nelson, Adult Tours Program Assistant
The Magnolia grandifloras in our collection are blooming now! Who doesn’t love a 12-inch wide flower that smells great? The commonly named Southern Magnolia or Bull-Bay is native to the SE United States from Eastern Texas, along the lower Gulf Coast to the Atlantic where it grows in loamy soils near water. It has proven to be very adaptable to different soils and this has allowed for its ability to be cultivated in many different climates. The largest M. grandifloras in their native habitat have been measured at up to 125′. In non-native climate gardens they tend to grow to about 80′.
This tree is a valued ornamental in gardens around the world because of its large flowers and dark green glossy evergreen leaves. It is used industrially for its beautiful hardwood to make furniture and cabinetry. The seeds are food for native southeast squirrels, possums, quail and turkeys. The leaves, fruit, bark and wood also are valued for their pharmaceutical properties.
Our collection M. grandifloras are located on either side of Arboretum Drive in the Magnolia section of the arboretum. These trees are quite large and most of its flowers are high up, but there are a few on the lower branches accessible for smelling that nice citrusy scent. Tour visitors from the Southern US assure me that this scent can be smelled at a distance down there, but up here in the Pacific NW one has to get up close to enjoy the scent. And, speaking of tours, these trees and other summer bloomers like the Hydrangea are featured in our Free Weekend Walks for the month of July. Join us any Sunday; we meet at 1:00 pm at the Graham Visitors Center.
April 19th, 2015 by Catherine Nelson, Adult Tours Program Assistant
Along Azalea Way this time of year, as many of you know, the Rhododendron cultivars, Redbuds & Dogwood Trees are putting on their show of stunning blossoms. Amongst all these flowering shrubs and trees it is sometimes hard to discern any individual plants, but its always worth it for me to stop at the group of Rhododendron occindentale at the North end of Azalea Way. These Rhododendron species, commonly known as Western Azalea, get my attention because in addition to the clusters of pretty flowers (and unlike most Rhododendron species) they have a wonderful scent. My nose could spend a lot of time near these shrubs. This grouping of about 10 shrubs (located in the very NW bed along with several other pink/orange flowering cultivars) were planted in 1946 and now each plant stands about 8-10 feet tall.
The R. occindentale is one of two native west coast Rhodies (the other being R. macrophyllum, our state flower) and is found mainly in the mountain and coastal areas of southern Oregon and Northern California. Because our climate and soils are similar, they are a plant that transfers quite well to our PNW gardens. They are a slow grower which can take sun or shade and seem to adapt to a variety of soils. Their native environments range from coastal marshes, river and lake sides and up to mountain meadows. But that’s not all – the other perk to these shrubs is that they can bear a lovely orange/red fall foliage color.
Come along on one of our Free Weekend Walks and enjoy a guided tour of these and many other collection plants in their full spring glory. No registration, visitors meet at the Graham Visitors Center at 1:00 pm each Sunday.
For more detail on these shrubs in their natural environment click the article link from Pacific Horticultural Society
March 21st, 2015 by Catherine Nelson, Adult Tours Program Assistant
In the old Nursery along Arboretum Drive there is a group of Chaenomeles cathayensis (Cathay or Chinese Quince) shrubs in full bloom. This cluster of three shrubs make for a huge display as they are about 15 ft. tall and 20+ ft. across. Covered in these lovely pinkish white flowers right now, they will bear very fragrant pear sized fruits in the autumn.
Known in Chinese as Mu Gua, this plant is native to China, Bhutan, and Burma where the fruits are used in traditional medicine.
These fruits are not commonly used in cooking as their European Quince cousins are. They are quite sour and must be blanched and dried in order to process them for consumption. According to Purdue University’s New Crop Resource, they are valuable for the “high content of organic acids in the juice, distinctive aroma, and high amount of dietary fiber.”
October 18th, 2014 by Catherine Nelson, Adult Tours Program Assistant
The Liquidambar styraciflua, or Sweetgum, is one of autumn’s most brilliantly colored trees, its leaves showing off every color in the spectrum.
The Liquidambar was wide spread, existing all over the Northern Hemisphere during the Tertiary Period (250-65 million years ago), but mostly disappeared due to glaciation during the ice age. Now this tree is native only to the SE United States and some areas of Mexico and Central America. These deciduous trees can grown to 80-100 feet tall & live up to 400 years. Its species name in Latin means ‘flowing with resin’ as the sweet resin in this tree was originally used for chewing gum.
They can be mistaken for maples as they have a similar palmate leaf. The Sweetgum leaf has 5-7 pointed lobes, but is usually flat along the bottom. They also have a distinctive spiky brown fruit in autumn.
Our free Weekend Walks 10/19 – 11/16 will take visitors to view this and other deciduous plants in our collection. Please join us. See Visit > Tours for more information.
July 27th, 2014 by Catherine Nelson, Adult Tours Program Assistant
This photo is of a native Thuja Plicata (common name; Western Red Cedar) and shows the great J-arm branches that these trees feature. Although the Puget Mill Company logged most trees on the site by 1900, this particular Thuja was perhaps overlooked by the loggers and is therefore one of the oldest and largest specimens in the arboretum. It is located between the Witt Winter Garden and Azalea Way.
This tree species was valued by the local Salish tribes who called it the “tree of life” as it provided them with bark for clothing, dried leaves for a medicinal tea, and planks for longhouses among many other uses.
Our August Free Weekend Walk’s topic is Native Plants & People; a knowledgeable guide will talk about this tree and various other native plants and their ethnobotanical uses.
May 4th, 2014 by Catherine Nelson, Adult Tours Program Assistant
Paulownia tomentosa, Common name Empress Tree
Right now this tree’s large purple panicled flowers, which look similar to foxglove flowers, are blooming and the scent is wonderful. There are several in the UWBG collection, most located at the North end of the park where the wetlands trail begins.
It is a very fast growing tree that can reach 80 ft. in height, and is prized for its large heart-shaped fuzzy leaves. The large size of young growth can be enhanced if the tree is pollarded yearly; the pruning encourages growth of leaves up to 16” across.
It is classified as an invasive plant in the Southern United States, where it sends out invasive roots and can take over the area it is planted in. The Paulownia here in the Pacific Northwest do not behave invasively, probably due to our cooler climate.
The name Paulownia is in honor of the Grand Duchess Anna Pavlovna of Russia, with tomentosa being derived from the Latin meaning ‘covered in hairs’.
Paulownia is cultivated as an ornamental tree in parks and gardens. It has earned the Royal Horticultural Society’s Award of Garden Merit.
In its native China, an old custom is to plant an Empress Tree when a baby girl is born. The fast-growing tree matures when she does. When she is eligible for marriage the tree is cut down and carved into wooden articles for her dowry. Carving the wood of Paulownia is an art form in Japan and China. In legend, it is said that the phoenix will only land on the Empress Tree and only when a good ruler is in power. Several Asian string instruments are made from P. tomentosa, including the Japanese koto and Korean gayageum zithers.
April 19th, 2014 by Catherine Nelson, Adult Tours Program Assistant
Rhododendron macabeanum is one of the finest big leaved Rhododendron species and has received the Royal Horticultural Society’s Award Of Garden Merit. It has large yellow/white flowers often blotched purple inside with an interesting bright pink stigma. The leaves are a dark glossy green and about 1′ in length with a light colored indumentum on the underside. It also bears a nice silvery young leaf and bright red bud scales.
Native to India at high elevations, this plant was introduced to the West in 1927. We have a wonderful specimen in the arboretum. It is blooming right now and is located between the SE corner of Loderi Vally and the Magnolia Collection. Our April Free Weekend Walks on Sundays at 1:00 pm will continue to feature this and other amazing Rhododendrons in the UWBG collection.