Elisabeth C. Miller Library logo Miller Library Home UW Botanic Gardens Home UW Botanic Gardens Home book graphic

3501 NE 41st Street, Seattle, WA 98195 | (206) 543 0415 | Open: | Library Schedule

Gardening Answers Knowledgebase

Browse the Knowledgebase

Search for gardening questions with researched answers, plus gardening tips, book reviews and recommended websites.




Recently Added Questions


A friend gave me a small bag of camphor wood chips. I have them in my car and like the smell. Someone told me that camphor can be toxic. Is is toxic to breathe, to burn, to human, to plants? Is it safe to just keep in my car and breathe?


Cinnamomum camphora (source of camphor wood) is in the Laurel family. According to Toxic Plants of North America (Burrows & Tyrl, 2013), "few toxicologic problems have been associated with the genus. However, when a camphor tree was planted in an aviary, 49 budgerigars died within 24 hours, apparently from its noxious fumes." As implied by its common name [camphor tree], all parts of the tree contain camphor. The intensity is greater in the leaves than in the wood. The tree's toxic properties have been known since the late 1800s, and most exposures are non-fatal and involve accidental ingestion of liniments that contain the oil from the plant. When inhaled, camphor is usually a mild irritant (perhaps not so mild at all if you are a bird!) and nervous system stimulant. It also contains low levels of toxic alkaloids.

If you wish to err on the side of caution, I would suggest not breathing the fumes, burning the wood, or using it in the garden (unless you are trying to suppress weeds, though the tree itself is considered a weedy species in some parts of the world, such as Australia). As you probably know, people have used camphor-based preparations in herbal and traditional medicine.

About medicinal uses and associated risks
About the tree
About the wood

The article "Camphor—A Fumigant during the Black Death and a Coveted Fragrant Wood in Ancient Egypt and Babylon—A Review," by Weiyang Chen, Ilze Vermaak and Alvaro Viljoen, offers a historical perspective, and does mention that the tree may have some phytotoxic/allelopathic properties as well (toxic to other plants).
"The fragrant camphor tree (Cinnamomum camphora) and its products, such as camphor oil, have been coveted since ancient times. Having a rich history of traditional use, it was particularly used as a fumigant during the era of the Black Death and considered as a valuable ingredient in both perfume and embalming fluid. Camphor has been widely used as a fragrance in cosmetics, as a food flavourant, as a common ingredient in household cleaners, as well as in topically applied analgesics and rubefacients for the treatment of minor muscle aches and pains. Camphor, traditionally obtained through the distillation of the wood of the camphor tree, is a major essential oil component of many aromatic plant species, as it is biosynthetically synthesised; it can also be chemically synthesised using mainly turpentine as a starting material. Camphor exhibits a number of biological properties such as insecticidal, antimicrobial, antiviral, anticoccidial, anti-nociceptive, anticancer and antitussive activities, in addition to its use as a skin penetration enhancer. However, camphor is a very toxic substance and numerous cases of camphor poisoning have been documented. This review briefly summarises the uses and synthesis of camphor and discusses the biological properties and toxicity of this valuable molecule."


I know that synthetic reeds are used in making some woodwind instruments like oboe and bassoon, but what plants are the source for the natural reeds? Is there a difference in sound quality between synthetic and natural reeds? Can the plants be grown in the Pacific Northwest?


There is an article entitled "Wind driven: A bassoonist nurtures reeds from rhizome to riff," by Diana K. Colvin, published July 21, 2005 in The Oregonian. Oregon Symphony bassoonist Mark Eubanks grows Arundo donax in the Portland area. He says that the plants grow best in areas where the temperature does not drop below 10 degrees. They are also sensitive to drying winds and ground freezes. They perform well in areas where grapevines would thrive. His reed-making business, Arundo Reeds and Cane, has since been sold, but the company website offers a history of how Eubanks started it.

Another musician in New Jersey, Lawrence J. Stewart, has also made reeds from the plant. Musicians' opinions on the sound quality of natural vs. synthetic reeds may differ but, in his experience, the sound seemed "very resilient and vibrant." Unlike synthetic materials, the structure and therefore the sound of the reeds made from plants can vary widely. An article ["Anatomical characteristics affecting the musical performance of clarinet reeds made from Arundo donax L. (Gramineae)"] from Annals of Botany, vol. 81, Issue 1, found that "good musical performance was associated with reeds with a high proportion of vascular bundles with continuous fibre rings, and bundles with a high proportion of fibre and a low proportion of xylem and phloem. Significant differences in these anatomical characteristics were also found between reeds originating from cultivated plantation plants when compared to reeds produced from agricultural windbreak plants."

This plant has been used for woodwind reeds for quite some time. According to "Arundo donax: Source of musical reeds and industrial cellulose" by Robert Perdue Jr. (Economic Botany, Vol. 12, No. 4, pp. 368-404), it may have been used in making flutes shortly after the late Stone Age.

The invasiveness of Arundo donax is essential to take into consideration. It is on Washington State Noxious Weed Control Board's quarantine list. It is also considered invasive in many other parts of the country, including California. If you can salvage reeds that are being removed from a natural area and put them to musical use, so much the better. But I cannot recommend cultivating a stand of Arundo donax for any purpose.


I know that Brugmansia has toxic and intoxicating properties. I heard a story about a railway carriage in Europe that was filled with the Brugmansia flowers. When the doors to the carriage were closed, the fragrance of the blooms caused the passengers to lose consciousness, and their valuables were stolen. Plausible, or urban legend?


Brugmansia, like the related solanaceous plant Datura, contains tropane alkaloids throughout the plant, including the seeds and flowers. One of these alkaloids is scopolamine. There are many tales of "Devil’s Breath," a processed form of scopolamine (as powder), or scopolamine-rich seeds being used by criminals in various parts of the world to drug their victims into unconsciousness. There is an article in The Guardian (September 2, 2015) which suggests it's unlikely that this substance would have been used to "zombify" travelers in Europe. There are, however, travel security warnings from the U.S. State Department about its use by criminals in Ecuador and Colombia.

A scientific article, "Volatile compounds emitted from flowers and leaves of Brugmansia X candida (Solanaceae)" (G.C. Kite and C. Leon, in Phytochemistry, 1995) states that volatile tropane alkaloids could not be detected in the fragrance of either flowers or leaves; the main volatile organic compounds emitted by the flowers are terpenoids, benzenoids, and indole. Those compounds can cause headaches but it seems unlikely they would act like a sedative.

The book Plant Intoxicants by Baron Ernst von Bibra (Healing Arts Press,1995) describes use of Datura seeds by criminals in India to knock out their victims. There are many traditional medicinal uses of Brugmansia among the indigenous tribes of Colombia, but the hallucinogenic effects are especially frightening. One tribe describes the pleasant scent of the flowers but warns that the plant is inhabited by an evil spirit and all who sit at the foot of the tree "will forget everything." (Source: Plants of the Gods, Richard Evans Schultes, Healing Arts Press, 2001). However I cannot find any confirmation for your colorful story of a train carriage full of drugged passengers among the Brugmansia flowers.


I am growing goji berry plants in my garden. I was hoping their growth habit would be more upright but they are sprawling wildly. Do you have suggestions for training them? Should I be concerned that they might become invasive?


Susanna Lyle's book Fruit & Nuts (Timber Press, 2006) says these shrubby vines are short-lived, peaking in berry production at about 5 years of age and typically living for 8 years or so. She advises planting them near a fence or trellis so that they can be trained up it; some sprawling is to be expected. Utah State University Extension's October 2015 article, "Goji in the Garden," offers general cultural information (while mentioning that the plant is a weed in some areas).

Lycium barbarum (goji, also called wolfberry and boxthorn) can be invasive (or at least aggressive) in some areas. An article by Vern Nelson in The Oregonian (August 17, 2008) mentions this tendency, and suggests containing them in a 4 by 5-foot square support structure. Be aware that "wolfberries take root wherever they touch the ground." This is worth bearing in mind, as is the fact that Lyle's book says "the extensive root system can help stabilize banks," which one could interpret to mean that removing unwanted plants might be a fair bit of work!

Suckering roots are only one way the plant spreads; seeds are another. Goji berry (boxthorn) is the "Plant of the Month" in the Whatcom County Master Gardeners Weeder's Digest from August 2006. Author Cheryll Greenwood Kinsley notes that when the plant was first introduced in Europe, people weren't enamored of the fruit but birds were, and now "the shrub has naturalized in Britain and is listed as a noxious weed on two continents and in at least some parts of several states, including Montana and Wyoming." She recommends keeping the birds away from it to discourage its spread.


Slowly but surely, what's left of my untended lawn is being overtaken by a small weed with fan-shaped leaves. It reminds me of a tiny Lady's Mantle. What is it, and is there any hope of getting rid of it without herbicide?


Your description sounds like Aphanes australis, whose common name is slender parsley-piert. The common name derives from the plant's leaves which resemble parsley, and the French 'perce-pierre,' meaning 'break (or pierce) stone.' It thrives in dry, exposed, or barren soils. North Carolina State University's Turf Center describes cultural control methods:
"Winter annual broadleaf weeds germinate in the fall or winter and grow during any warm weather, which may occur in the winter, but otherwise remain somewhat dormant during the winter. They resume growth and produce seed in the spring and die as temperatures increase in late spring and early summer. They quickly invade thin turf areas especially where there is good soil moisture. Shade may also encourage growth. Many have a prostrate growth habit and are not affected by mowing. A dense, vigorous turf is the best way to reduce the encroachment of winter annual weeds. First, select adapted turfgrass cultivars for your area and then properly fertilize, mow, and water to encourage dense growth."

It sounds like lawn renovation might be a good idea. If the parsley-piert has intense competition from a happily growing lawn, it will not thrive. Seattle Public Utilities has good resources on lawn care.