Updated: Jan 31, 2022
I'm pleased to introduce our guest writer Kris Kubly. Kris, along with his wife Penny, are the proud stewards of 182 acres of ecologically valuable land near New Glarus, WI. For all the practitioners out there struggling to propagate our rare prairie plants, I believe you will find Kris's story enlightening and uplifting.
As I stood at the top of the hill on a sunny September day, a bright blue shape on the slope below caught my eye. “Just a snack food wrapper,” I thought, as I picked my way down the hill. When I reached the object, I was surprised to find a low-growing plant with glossy green leaves and brilliant blue flowers. I consulted a book on prairie plants, which identified it as a downy gentian (Gentiana puberulenta).
The hillside was a long-neglected prairie remnant on sandy, rocky soil overgrown with brambles and honeysuckle bushes. Months earlier, my neighbor had volunteered to make an exploratory run down the hill with a tractor and brush mower. After watching the tractor slowly bounce down the steep slope, I decided additional mowing on the hillside would not be wise and any further clearing would have to be done manually.
The gentian was found on the previously mowed strip of hillside. Based on this discovery, I reasoned that if one mowed strip had yielded one such plant, this hillside must have dozens more. My optimistic projection was disproven over the course of the next several years as the entire hillside was cleared of invasives, but no additional gentians were found. The lone gentian received a wire enclosure and periodic weed control. The hillside path to the enclosure became worn from my frequent trips to check on its condition and admire its appearance.
Seeds were collected from the plant in the fall for the next several years, and they were scattered on the hill near the parent plant. The seed production was extensive, with each of the dozen or so seed pods containing many seeds.
After several years of successful seed production, a sudden change occurred: the seed pods contained numerous caterpillars but very few seeds. The next year, caterpillars were again present and few seeds were found. The caterpillars were light colored and about 0.4 inch/10mm long. Photographic images of the caterpillars were emailed to the University of Wisconsin-Madison Entomology Insect Diagnostics Lab. Their reply indicated that the caterpillars were likely the larvae of the Endothenia hebesana moth, which feeds on the developing seeds of host plants including Gentiana. A bacterial insecticide was recommended for caterpillar control.
Because there was the possibility of adverse effects of the insecticide on pollinators, the plant was instead covered by wire mesh screening attached to a shortened tomato cage after pollinator activity was observed. Each fall after the seeds were collected and the plant had gone dormant, the stems were cut and burned, in order to eliminate any larvae that might be attempting to overwinter inside.
The screening of the plant proved successful by nearly eliminating caterpillars and restoring the seed production back to the original level.
However, after 15 years of collecting and spreading seed, we still didn’t have another downy gentian to show for our efforts. This led to the decision to seek help from a native plant nursery who agreed to try to raise plants from our seeds. We provided approximately 200 seeds, which represented a small percentage of the total seed production for the year. After about 18 months, the nursery sent an apologetic email, explaining that they were only able to germinate a single plant. I was overjoyed. Although the nursery had advised me that downy gentians can likely self-pollinate, I had been skeptical that our lone plant could produce viable seeds.
Following the nursery’s recommendation, a soil probe was used on the hillside to locate a suitable planting spot without bedrock directly under the surface. After much probing, a rock-free spot was located and the gentian was planted inside a wire mesh enclosure. Water was provided during dry periods, and the young plant grew steadily. Two years after planting, it surprisingly produced four bright blue blossoms.
At the same time that the new plant produced its first flowers, another discovery was made inside the enclosure of the original plant. There, nearly hidden in a corner of the enclosure, was a tiny downy gentian with a single blossom. This was likely the result of our seeding efforts but it’s impossible to know from which year’s seed this plant germinated.
The success rate of seeds distributed directly on our site is very low, on the order of one plant per tens of thousands of seeds. The single plant that resulted from seed sown on our site could have required as much as 15 years to transition from seed to blooming plant. The nursery germination process shows a vastly higher success rate of about one plant per 200 seeds and a fast transition from transplant to flower- and seed-producing plant.
The appearance of the two new gentians after so many years of effort is extremely rewarding, as is the discovery of a process which will hopefully provide a viable seed supply and a means of creating many additional new plants in the future. Given enough time, the lone survivor gentian and its offspring might someday carpet the hillside with brilliant blue fall flowers.