Many Visitors Have Asked About Island Flowers Now in Bloom Nature Notes By

Patricia Martin

It’s amazing how quickly the spring flowers fade and the summer flowers suddenly appear. With the shot of warm weather and rain, new blooms have shown up on the Island. At various events during the Lilac Festival, I was asked about several plants that are flowering. The most asked question is about a white, pink, or purple flower that is blooming in open areas around the Island from the shore road, to the Bluffs, to old fields. Most people seem to think that this plant is a phlox, but it’s not. The plant in question is a mustard known as Dame’s or Sweat Rocket (

Hesperis matronalis). This plant has also been called Mother-of-the-Evening, as the flowers smell sweeter at night. One easy way to tell it from Phlox is that Phlox has five petals and Dame’s Rocket has only four. All plants in the large mustard family ( Cruciferae ) have the unusual combination of four petals and six stamens. Most of us think of mustards as being yellow-flowered, and many are; however, there are quite a few that are pink, white, or purple as well.

Dame’s Rocket

Dame’s Rocket stands two to four feet tall and blooms from late spring through summer. The leaves are alternately arranged along the stem with a short stalk or without a stalk. They do not have an indented leaf base and the upper surface of the leaves has fine, downy hairs with the lower surface having branched hairs. The margins of the leaves are usually finely toothed, though they may be smooth to undulating. The blade is three to four times longer than broad.

Perennial Bachelor Button

The four petaled flowers are arranged in open clusters at the end of leaves stalks. Each flower is about an inch in diameter and the inflorescence is fragrant. Typical of the mustards, the fruit is a long (up to five inches) cylindrical capsule.

Valerian

These are very showy flowers and are not native to Mackinac. They were brought here as garden flowers, originally from Europe, and have escaped into the disturbed areas of fields and roadsides. This is not particularly unusual, as approximately 25 percent of the plant species on the Island are non-native and have been brought in deliberately by people for flower gardens and agriculture, not to mention in bales of hay. In addition, alien plants have been transported by birds and even by the water.

Another garden plant that has escaped into the edges of roads is the Perennial Bachelor Button or Mountain-bluct ( Centurea Montana ). Locally folks around here call it Rapid Robin, though lately people who have been asking me about this plant have referred to it as Wild Bergamot, which is in the mint family. The mint family is easily identified by the square stems of the plant. Perennial Bachelor Button is in the Aster family ( Asteraceae ) as are Dandelions and Daisies. It doesn’t have square stems and has a flower head composed of a number of flowers compacted together.

This Bachelor Button is a knapweed, commonly called a star thistle. The heads are made of many flowers, which are all tubular, though the marginal ones are often much larger, spraying outward, which give it the look of a thistle. The flowers of knapweeds are usually rose-purple with the fringed bracts covering the base of the flower head. In the case of the Perennial Bachelor Button, the outer edges of the flower are a brilliant blue with the center being more rose colored. The flower heads are quite large and are terminal on the end of a stem. The leaves are a broad lanceolate to elliptic in shape along an erect stem standing two to three feet tall. The stem arises from an underground stolon and, as its name implies, it’s a perennial flower.

These plants originated in the mountains of central Europe and have been cultivated as garden favorites. They’re commonly found on Mackinac in waste places, woodland borders, and along roadsides. Potowatami Road, just behind the East Bluff, is a prime area for finding them. In Michigan, they’ve been collected in the wild in only five counties.

A cousin, another foreign knapweed that has become quite an invasive species in North America, is known as Spotted Knapweed, which will bloom later in the summer. It’s a plant that tends to take over an area and push out other species.

One other plant that is just now blooming in abundance, which is again an escaped garden flower, is the Garden Valerian ( Valeriana officinalis ). It was cultivated for its very fragrant flowers and has been used as a medicinal herb to treat migraines, among other ailments.

Valerian has stem leaves pinnately divided into five to 25 lace-shaped leaflets. The plant stands two to five feet tall and has small pale pink or white funnel-shaped flowers, one-eighth to one-fourth inches long, found in branching clusters. They bloom in the summer months.

This plant is a Eurasian native and is commonly found on roadsides, ditches, shores, fields, and the borders of woods. On Mackinac it grows in abundance along the East Bluff and along the shore road on the southern part of the Island.

There are many native plants blooming now as well, from roses to Lady’s Slippers, to Anemones, and Coralroot., but the plants listed above are those that people have asked me about. Keep your eyes open as you walk or ride about the Island. The flora is constantly changing.

Trish Martin is a year-around resident of Mackinac Island, has earned a master’s degree in botany from Central Michigan University, and owns Bogan Lane Inn.