Almost Last But Not Least

As the growing season winds down, it’s getting harder to find wildflowers in bloom. But there is one Missouri wildflower that is just now coming into flower in our prairies and rocky glades. Although not a large plant (up to 20 inches tall), downy gentian (Gentiana puberulenta) has large flowers for its size and is arguably the most beautiful of our blue wildflowers. Julian Steyermark, author of "Flora of Missouri," described the flower as having the deepest dark blue-purple color of any of Missouri’s native species. Its cup-shaped flowers must taste good to local insects because it is common to find plants with somewhat ragged, partially consumed flower petals.

To experienced eyes, downy gentian stands out in our prairies and glades throughout the spring and summer, growing usually in a clump of short stems with opposite, hairless, almost succulent foliage. Even without flowers, it is difficult to confuse with other prairie species. Botanists and ecologists like to see it on a site because it usually grows only where the native vegetation is intact, where human alteration of the vegetation has been minimal. By October, fewer people visit our prairies and glades and the full glory of downy gentian often goes unnoticed.

It is tempting to speculate why downy gentian and a few other late-blooming species procrastinate in opening their flower buds until the first frosts of autumn are imminent. In the case of this gentian, perhaps it takes the whole growing season for the small plant to store energy to develop such large  flowers. Perhaps there is no reason to flower earlier because the plant is somewhat frost-tolerant. Pollinators should be abundant and working hard as the growing season winds down and soil moisture can be greater in the fall. Rapid seed development is required for them to reach maturity before the arrival of winter's bitter cold. Growing the species from seed is described as difficult, perhaps due to the failure of some seeds to reach maturity before the plant enters winter dormancy.

Whatever the plant's strategy, downy gentian is in flower this month. If you need another reason to get out and explore our prairies and glades, in addition to the cooler weather and beautiful autumn skies, downy gentian should provide that impetus.

Photos by James Trager, used by permission.