Matt Ferguson Visits the Arnold Arboretum in Boston.

Matt Ferguson is an acupuncturist and Chinese herbalist in our Seattle Office.  Matt has cultivated his herbal expertise through the years through his efforts as adjunct faculty at Bastyr Center for Natural Health teaching Chinese herbal preparations and in the Chinese Herbal Medicine Dispensary as herbal coordinator. 

Arnold Arboretum

Recently I had the opportunity to go on a little Chinese herbal live plant pilgrimage at the Arnold Arboretum in Jamaica Plain, Boston.  Earlier this year I participated in a workshop taught by Jean Giblette who came to Bastyr University as a guest lecturer on cultivating Chinese Herbs in the United States.  In a correspondence with her later that summer I mentioned my upcoming visit to the Arnold arboretum and she recommended I stop in at the Arnold Arboretum’s Hunnewell Visitor Center to pick up the guide map to the arboretum’s collection of Chinese medicinal.  Upon my arrival at the Arboretum I picked up the brochure which is a nicely laid out  self guided tour  created in 2009 by her organization The High Falls Garden and the students at the New England School of Acupuncture.  During my visit I learned that the arboretum was designed by the Olmsted brothers in the late 1800s which was poignant for me coming from Seattle as the Olmsted brothers were the same landscape design firm that laid out the Seattle park system. They were also well known for the design of Central Park in New York and what is referred to as the emerald necklace of connected parks and boulevards in Boston.  The most obvious reminder of their legacy for me in Seattle is the scenic ride from Seward Park north along Lake Washington Boulevard pas the Mount Baker Boathouse and right on up to the Washington Park Arboretum.

The brochure included a map of the site with images and information on eleven species of trees  and shrubs from which the  Chinese medicinals  are harvested.   Using this little treasure map I was able to hike through this tree park in  four hours and locate the majority of the trees in the brochure  plus one that wasn’t on the list.  As an herbalist who has spent a lot of time with the dried herbs in their prepared form I feel obligated to go visit the live plants when I get the chance. The timing of the visit in the fall was also propitious as there was the possibility of obtaining a few seeds from the trees to take home and try planting on my return to Seattle.

Gingko Tree


I think the highlight of the tour was seeing the collection of female ginkgo trees that were laden with ginkgo nuts.  I planted a female ginkgo tree in the Bastyr University herb garden fifteen years ago and I’ve yet to see it produce anything resembling a nut as it is an extremely slow growing  but long living tree which at present stands only about six feet tall.  Ginkgo trees are readily found throughout Seattle but most of them are male as landscapers usually avoid planting the females as the outer fleshy coat of the ginkgo nut decays to produce a foul odor once they drop from the trees in the fall.  The odor is described as being vomit-like or similar to the stench of rotting flesh.  It is suspected that this benefitted the tree’s survival as carnivores would be attracted by the smell, eat them, and distribute the seed around the forest.  This theory is supported by research studies showing that the seed germinates more effectively when the outer flesh is removed from the nut which is what would occur during its transit through the digestive tract.  The Ginkgo nut is used in Chinese medicine in a few classic formulas but more commonly used as a nutritious food, wherein the nut is cleaned of the outer flesh and fried until the seed coat pops open revealing a green edame like flesh that can be eaten a few at a time.  The ginkgo nut Bai Guo(mandarin pinyin name) has an astringent quality that  is used  traditionally for frequent urination and as a lung tonic in the treatment of cough, asthma and tuberculosis.  It has a long history of being planted at sacred sites around China often living to be thousands of years old.

Next on the list of curious plants were the Honey Locust Trees located on Peters Hill which is the highest point of the 265 acre tree museum.  This somewhat invasive tree is a fearsome sight to behold with multiple clusters of 3 to 4 inch spines emanating directly from the trunk of the tree.   This formidable characteristic probably benefited the survival of the species by discouraging any animals from browsing its bark.  In traditional Chinese medicine two different parts of this tree are used as medicinal herbs. The actual spines called Zao Jiao Ci which translates to something like “dispersing swellings spine” is harvested and dried for use topically for abscesses and boils.   It is boiled in vinegar and made into a paste and applied topically to encourage them to come to a head and discharge any pus.  The bean pod Zao Jia is used in low doses for cough with thick sticky mucous and some parasitic infections.  It should be used cautiously due to its toxicity. Recent research using an extract of this plant has led to some interest in its potential as an anticancer agent.  It has to be noted that plant materials with varying degrees of toxicity have been used traditionally in cancer treatment in a manner consistent with modern chemotherapy drugs in which variably toxic constituents are used to retard runaway cell growth.  A significant difference in the approach of traditional Chinese medicine is these toxic medicinal are usually given with other tonifying or regulating herbs to simultaneously protect the body from this onslaught and actually allow the body to tolerate the treatment for longer periods of time.

My other visit was with Phellodendron Amurense commonly known as the Amur Cork Tree.  The tree bark referred to as Huang Bai is used in Chinese medicine for its drying and heat clearing qualities.  Of the herbs mentioned so far it is more commonly used in day to day herb prescribing.  The tree bark has a bright yellow color which is consistent with other berberine containing plants which have similar functions of clearing heat and drying dampness (think of inflamed red sticky moist type presentations).    They had a few well established trees with very thick bark with blue black peppercorn sized fruit hanging on the branches.  This herb is included in Ba Wei Di Huang Wan a classic formulation of eight herbs which may be used for some patterns of night sweats.  The Huang Bai is used in this case to clear what we call deficiency heat that floats up due to a relative lack of yin moistening qualities that the remaining herbs in the formula address.

Another favorite was their Mulberry tree of which three different medicinal are obtained from various parts of this fast growing tree.  The fruit, Sang Shen Zi can be picked fresh from the tree and eaten or dried for use in making tea.   The leaf, Sang Ye has a cooling moistening quality used in formulas for colds and flu.  The tree branch, Sang Zhi is used to relieve body pain in the upper part of the body. The root bark of the tree, Sang Bai Pi is used for wheezing and cough and edema.  This versatile tree is also noted as the favorite food of silkworms so it was crucial in the silk making industry of China.  In one of the classic texts on pulse taking they refer to the irregularly eaten edge of the mulberry leaf by a sick silkworm as a visual guide to what a specific type of pulse quality should feel like under the fingers. Interestingly enough these sick silkworms (actually immature silkworms infected with Beauveria bassiana a contagious fungus) are dried and used as a Chinese medicinal for spasms or convulsions.  They are known as Bai Jiang Can which translates as white mummified silkworm. The white color is created by the fungus that enters through the skin and fills out the whole body of the insect.  This tree is also associated with another Chinese herb called Sang Ji Sheng “mulberry parasite” which grows as a parasitic plant on the mulberry tree and is used for stiffness or joint pain in the lower back and legs.  I planted a Mulberry in the Bastyr herb garden about fifteen years ago where it has now grown thirty feet tall and produces multitudes of sweet purple white mulberries in late August.

They have a bi-lobed leaf magnolia from which the bark is harvested and referred to medicinally as Hou Po.  It is often used for abdominal distension and in formulations with other herbs that treat constipation, flatulence, reduced appetite, vomiting and diarrhea.  In my search for this tree on the grounds of the arboretum I came across another commonly used Chinese herb that wasn’t on the guide list.

Du Zhong – Eucommia Bark

Du Zhong

Eucommia Ulmoides is harvested for its latex infused bark which is referred to as Du Zhong when used as a medicinal.  The bark is sustainably stripped off the tree and then run through a milling machine that breaks it up so that it resembles some sort of ersatz snake skin.  It is considered a mild yang tonic with the ability to strengthen the sinews and bones.  The visual cues for the plants ability to do this are the sinuous strands of latex that appear upon breaking up the bark. The plant thus providing the image that it may be helpful for reconnecting sinews and bones.  In combination with other herbs it has been used traditionally for treating low back pain or threatened miscarriage.  In the west the plant drew attention as it is the only rubber producing plant that can survive in temperate latitudes.  For this reason it appears in many tree collections.  There used to be a sixty foot tree growing in the University of Washington’s medicinal herb garden until it was toppled in a heavy windstorm in 2003 however there are three living trees scattered around the Washington Park Arboretum in Seattle.  When the leaf is torn apart the very fine strands of natural latex in the leaf can be seen. In China the leaf has been more recently used as a substitute for the bark as it contains similar constituents and obviates the need for the more traumatic harvest of the bark.   While the tree is known to contain four percent natural latex I have not see any use of it historically as a reliable resource for latex.  Nor have I read of any accounts of adverse reaction from patients with latex sensitivities.  The plant list of constituents for the plant includes gutta percha a natural substance that was used as an insulating covering for the first undersea telegraph cables until it was substituted with synthetic alternatives.  Recent research has shown plant extracts having a potentiating effect on male hormones which would seem to concur with its traditional use as a Yang tonic.

Mei Gui Hua (Rosa Rugosa) is located on the Arboretum guide and is occasionally used in Chinese medicine.  The bud of the flower is typically harvested and dried for use in teas for stress related disharmony of the digestive tract and mild PMS symptoms.  It is easily spotted around Seattle as the low shrub is a favorite of many landscapers.  I pass by long hedges of it along the walking path border strip up on Seattle’s Westlake.  A couple of dried Mei Gui Hua buds is a nice fragrant addition to a pot of green tea.

Huai Hua Mi also known as the Pagoda tree flower bud is a useful herb for stopping bleeding especially bleeding hemorrhoids and other intestinal bleeding disorders. It is an attractive tree which is frequently planted in gardens as an ornamental. The flower “Huai Hua”and the fruit “Huai Jiao”is also used for bleeding disorders. The plant contains rutin which has been shown in some animal studies to be helpful for varicosities and that it demonstrates anti-angiogenic qualities that may be helpful for some cancers.

He Huan Pi and He Huan Hua are the bark and flower of Albizia Julibrissin commonly known as the Silk Tree Albizia.  It is a popular ornamental tree due to its impressive display of white and red tussled flowers and attractive leaves.  There is a nice one growing alongside the walking path in the Bastyr garden and they can be found frequently around Seattle.  In Chinese medicine it is added to formulas for bad temper, depression, insomnia, irritability and poor memory due to constrained emotions. The bark, used in large doses is also useful for pain and swelling secondary to physical trauma.

I have to admit there were a few herbs I didn’t get to on the list as I was distracted by the large variety of hawthorn trees planted on site. While I was walking through the hawthorn section of the arboretum I came across Craetagus Pinnatifida which is the large fruited crataegus cultivated in China for use in the treatment of food stagnation.  This disorder usually manifests as epigastric and abdominal distention and pain with poorly digested food in the stools.  Other uses for the fruit are chronic dysentery like disorders, post partum lower abdominal pain and more recently for hypertension, coronary artery disease and elevated cholesterol. The fruit , referred to as Shan Zha is sliced and dried to be added into formulas or used on its own as the main ingredient in jams, jellies, dried fruit leather, wine, or syrups.   Note that one popular text discouraged the use of eating large amounts of this fruit during pregnancy for fear it could damage the fetus.   Ninety different crataegus species are listed in the arboretum’s plant inventory database; evidently Charles Sprague Sargent the first director of the Arnold Arboretum had a strong interest in hawthorn trees.  If you plan to visit the Arnold Arboretum they provide a searchable inventory on their website of all the plants in their collection.   On the inventory list they provide grid coordinates that can be used to locate any particular tree on the property.  Various species of crataegus with similar medicinal properties can be found fruiting in the fall around Seattle though I’ve yet to locate the large fruited Pinnatifida.  I guess I’ll have to search out some seeds and start my own orchard.  I’m also inspired to come up with my own walking guide to Chinese medicinals in the Washington Park Arboretum as I’ve observed they have a pretty extensive collection of correct tree species from which various herbs in the Chinese Materia Medica are harvested.

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