Mystery fan that I am, I’ve long been aware that some ornamental plants are toxic. They are often used as murder weapons in whodunits.
Susan Wittig Albert has written a series of entertaining mysteries such as the one at left, Witches' Bane, each of which focuses on one plant. Mind candy, but you do learn something about herbs!
Plants’ toxicity can range from mild skin irritation to death. Considering its tough, hairy leaves, I doubt that anyone would accidentally down a lethal dose of digitalis by eating foxglove foliage in a salad. However we need to be aware of the deadly potential of some other ornamentals.
A few years ago, monkshood (right), a classic perennial, enjoyed a surge in popularity for its interesting blue flowers. A member of the aconitum family, all parts of this plant are poisonous. Aconitum was used by Aleutian Islanders as an arrow poison for their harpoons. In the Middle Ages, it was also called wolf’s bane because it was thought to ward off werewolves. If you do grow it, wear disposable gloves when handling it.
Another classic blue flower, delphinium, is also toxic. It is botanically related to aconitum. One member of the clan, larkspur, is toxic to cattle. Most delphinium do not like our humid heat, but the hybrid belladonna (left) does well once established. It is useful for its intensely saturated blue flowers. Do not confuse it with the belladonna used by ladies in the Renaissance to dilate their pupils. That one is the deadly nightshade containing atropine, which your eye doctor still uses to dilate pupils. It also contains scopolamine, a sedative believed to have been taken by Juliet to put her into a coma “for two and forty hours.”
For exotic flower power, it is hard to top Angel’s Trumpet, Brugmansia (right), with its huge six-to-10-inch pendulous trumpet shaped flowers dangling from the five-to-10-foot shrub. It is very closely related to Datura which has upright trumpet-shaped flowers. This family of plants includes those used by indigenous people of the Amazon as an arrow poison. All parts of both genera are poisonous.
The castor bean, Ricinus cimmunis, is another dramatic accent plant with burgundy leaves (left) as large as dinner plates. This fast-growing annual can reach up to 20 feet tall and three to six feet wide. The seeds are used to make castor oil and the deadly poison ricin. Hand washing after handling is recommended.
Most gardeners want to avoid having potentially harmful plants around pets and people, yet some common garden plants have some degree of toxicity. For example, lilies are toxic to cats, causing severe kidney problems. And it comes as no surprise that flowering tobacco is poisonous.
One can look up various plants online. The Thompson and Morgan catalog is a good reference for many common plants. Select Seeds clearly indicates poisonous selections.
My garden is a personal Eden. Hoping it is never marred by unintended consequences, I try to plant selections which bring only the joy of their beauty.
If master gardener Ann Bartlett has ever used her arcane knowledge of toxic horticulture in the commission of homicide, these heinous crimes have as yet escaped detection and she remains unpunished and at large.