When we write about gardening and post on social media, garden writers usually choose bright, pretty pink flowers or robust tomatoes as our subjects. Yet, many plant lovers can enjoy flowers and also get a kick out of growing edgier plants.
I live with one such plant lover. In fact, he loves spines and poisonous seeds so much that our daughter and son-in-law gave him Amy Stewart’s book Wicked Plants, The Weed That Killed Lincoln’s Mother & Other Botanical Atrocities (Algonquin Books, 2009) for Christmas last year. He likes to read it right before nodding off at night…
I thought I’d share with you some of Stewart’s insights into wicked plants, and list several that thrive in our entryway or rock garden.
Datura and Nightshades
Several deadly plants make up the nightshade, or Solanaceae, family. The one we grow every year (it comes back with a vengeance) is Jimson weed, or Datura stramonium. The entire plant is somewhat poisonous, but the real danger lies in the seeds inside the fruit pod that remains after the flowers fade.
I admit I love the flowers and watching hummingbird moths feed off the blooms, which open at dusk. According to Stewart, Jamestown colonists found out the hard way about the toxic alkaloids in Jimson weed. In fact, the name has evolved from its original moniker of “Jamestown weed.” The Jimson weed is the dry cousin of other toxic nightshades and grows naturally in some of the worst conditions of the desert Southwest.
Castor bean (Ricinus communis) is a member of the Euphorbiaceae family. It’s known for the ricin in the plant’s beans. Eating only a few of the seeds can kill a person. Like the Jimson weed, the toxic beans grow on an otherwise gorgeous plant. In full sun, we’ve had them shoot from seed to 10 feet tall in a summer growing season. The large leaves of the plants we’ve grown turn a dark bronze color. Also like the Jimson weed, the fruit can explode when dried out and scatter the toxic seeds. if you decide to plant this potentially deadly ornamental, you must remain vigilant about cutting off the fruit. I don’t have photos of our castor beans, probably because I keep a distance. But here is a link to more information and some excellent images of the plant and beans.
The spinier and spikier, the better for our sunny hallway. Relatives of the castor bean in the spurge family include the lovely Crown of Thorns (Euphorbia milii). It also has a sticky, white sap called latex that can irritate the skin. I can’t imagine any animal chomping on the thorny branches, but I’ve seen deer eat rose branches, so it’s good to make sure dogs don’t eat the euphorbia. Euphorbias also include poinsettias, which are not truly poisonous, but can cause irritation if the toxins from leaves contact your eyes or stomach problems if children or pets eat the leaves.
Stewart includes larkspur among her “Dreadful Bouquet” flowers. Larkspur is a member of the Delphinium family, and sometimes, the names are interchangeable. Plains larkspur plants are found throughout high plains of New Mexico, Colorado and Wyoming. The plant has dangerous levels of alkaloids in seeds, flowers, sap and leaves and can lead to death in cattle who consume the plains flowers at and after flowering. I love the early spring blooms of larkspur, which reseed between rocks in our garden and took over most of a bed last year. I’ve never seen deer damage, and as long as I wear gloves when handling the plant and avoid taking bites of it, I’m good.
Oleanders are popular shrubs and hedges in warmer Southwest climates (zones 8 through 10). They have long, slender leaves and colorful flowers. Because the plants grow quickly and need little care, they’re popular choices in landscapes. The plant’s sticky sap carries several toxins, including oleandrin, which can cause nausea and vomiting and affect heartbeat. People have been known to commit suicide by eating the plant, but the main concern is to keep curious children away, since it takes eating less to make them seriously ill. It’s too cold here to grow oleander, but we have a beautiful cousin of the plant that has a similar milky sap, a Desert Rose (Adenium), that we keep as a houseplant in winter.
The poppy (Papaveraceae) is a favorite Southwest plant. Many species of poppies have toxins that can hurt animals. After all, Papaver Somniferum is the plant that supplies opium. The opium poppy is illegal to grow, but seldom regulated, says Stewart. That’s largely because of how many plants it would take to supply an individual with enough opium to maintain a habit. Our poppies have spiky leaves that distinguish them from the smoother foliage of an opium poppy.
Other Common but Wicked Plants
Stewart’s book breaks down dangerous plants by plant families and other categories, such as phototoxic plants. These have sap that can burn the skin when exposed to light and include the rinds of limes and other citrus fruits.
One of our favorite summer annuals is Lobelia, which also is called Indian tobacco because some ingredients in the plants cause effects similar to nicotine. In small amounts, lobelia can’t hurt you, but it can be toxic in large doses if used as an herbal remedy. I also love, love, the red bird of paradise, another warm climate ornamental shrub. But Even sweet peas and tulips have toxins in various parts of the plants or bulbs.
The bottom line is this: All gardeners should use caution when choosing plants for their home or garden to make sure curious pets and children are safe (this is an extensive list of both, and toxicity ratings, from California Poison Control). On the other hand, growing a spiny or dangerous plant can appeal to adults and older children, and be a great introduction into plant care and the gardening bug!