Jennifer Schultz Nelson
Extension Educator, Horticulture
Sometimes it is a stroke of luck to take a chance and buy a plant you don't know much about at the garden center. I am a sucker for plants that look different, interesting or unique. In a perfect world I would go home and thoroughly research the plant before making my decision. The reality is often I am at a garden center that is a good distance from home and it wouldn't be easy to make a return trip. Many times that plant ends up in my cart. I've had good and bad results with this method.
One plant that jumped in my cart via this method late last summer was costmary, Chrysanthemum balsamita also known as Tanacetum balsamita. There has been some disagreement among scientists as to which genus this plant belongs. This plant was displayed among herbs at the nursery where I purchased it. I love to have unusual herbs in my herb garden, so it immediately caught my eye.
Another common name listed for this herb in the signage near the plants was "Bible Leaf". That intrigued me -- it sounded like this plant had some interesting story behind it, another plus in my opinion.
The signs also described fragrant foliage and a small "daisy-like" flower late in the season. The oval, serrated leaves have a pleasant fragrance, some call it a "balsam" fragrance, but to me it seems a bit medicinal, somewhat like a sweet eucalyptus. I didn't see any flowers on the plant I was purchasing, but since the sign said "daisy-like" and the genus listed was Chrysanthemum, I pictured a flower something like a fall mum, but smaller.
The plant seemed like a winner to me. Flowers late in the season were what finally sold me. I am always looking to add plants to my garden which flower late in the season. New flowers in the late summer and fall reinvigorate the landscape.
I planted my costmary plant with its compact mound of foliage in full sun along a path leading to our patio, thinking that brushing it in passing might release some scent from the foliage.
I noticed that the tag in the pot listed a different Latin name-- Tanacetum balsamita. That raised a warning flag to me. Tanacetum is the same genus as the herb tansy, a plant I purchased at a community plant sale that has an incredible will to survive.
Tansy is a bully in the garden. I purchased the offending plant at a community plant sale as a na´ve high school student trying to put together her first perennial/herb garden. The plant has fern-like foliage with a similar medicinal scent as costmary, and is supposed to have insect-repelling properties. The flowers look like yellow buttons held in flat clusters. I learned quickly to remove about three-fourths of the sprouts of this plant each spring to prevent it from suffocating every other plant in the garden.
Years later my dad plowed my garden under while I was in graduate school. I was very upset by this turn of events and secretly cheered when my dad complained about a plant that kept coming up in the spot where my garden had been. It was the tansy.
Back in the garden at my house, I wondered whether costmary would turn out to be a bully like its cousin tansy. So far it has behaved itself, but descriptions of this plant advise regular division to keep costmary under control.
I waited eagerly for my costmary to flower this summer. Unfortunately the flowers were not what I had expected. The "daisy-like" flowers promised in the nursery's description were in fact yellow and button-like, much like tansy. By the time the plant flowered, it was very leggy and flopping over.
Since the flowers were such a disappointment, I didn't feel bad cutting them off. This improved the plant's appearance immensely. It also prevents the plant from reseeding everywhere. The plant has filled back in and is a nice compact mound of foliage again. Next year I plan on removing the flowers as they appear, to keep the plant looking attractive.
Costmary's use dates back several centuries. At one time it was found in just about every herb garden. Costmary was both a medicinal and culinary herb in medieval times. Its fragrant leaves were used as a strewing herb to cover odors, and another common name, alecost, hints at its use as a flavoring in beer. It is also thought to have association with the Virgin Mary. Another common name, Bible Leaf, refers to use of the fragrant leaves as bookmarks in a person's Bible. If the pastor's sermon was a little too long, the strong scent of the leaf in a parishioner's Bible would help keep him or her awake! While it wasn't quite what I expected as far as its appearance, costmary's history makes it a keeper for my garden.