Biologists, land managers and researchers meet to discuss native Clover conservation in Kentucky

By: Tara Littlefield

Clovers (Trifolium sp.) are well recognized by the public primarily because of their role as a forage crop and lawn weed.  In Kentucky, we have 12 species of clover, but only 3 are native to our state, Kentucky Clover (Trifolium kentuckiense), running buffalo clover (Trifolium stoloniferum), and buffalo clover (Trifolium reflexum). All of our native clovers have declined greatly since European settlement and are state or federally listed as threatened or endangered. Historic accounts from pioneers and historic collections of native clovers indicate that our native clovers may have been more common in the woodlands of our state, particularly in the Bluegrass Region. Our native clovers have common names associated with buffalo since their associated habitat historically occurred mostly along buffalo/animal trails through the forest, which the Bluegrass Region is known for, large ungulates grazing on the grasses and forbs in our woodland systems.

In an effort to increase coordination and collaboration focused on priority native clover (Trifolium sp.) conservation projects in Kentucky, close to 30 botanists, ecologists, researchers, students, and land managers met in late February 2021 to discuss all things native clover (Trifolium sp.).  Species of focus included the globally rare and newly described Kentucky Clover (Trifolium kentuckiense), the federally endangered running buffalo clover (Trifolium stoloniferum), and the state threatened buffalo clover (Trifolium reflexum). 

The Kentucky Plant  Conservation Alliance coordinated the meeting and facilitators from the Office of Kentucky Nature Preserves, Virginia Tech University, Eastern Kentucky University, Austin Peay University, University of Michigan, and Cincinnati Zoo presented information on the current status (population ranks and trends), current conservation measures (land protection and management efforts), current research (life history, management needs, and genetics), as well as seedbanking and propagation efforts  The goal of the group is to work more collaboratively together to prevent the extinction or extirpation of these native clovers.  If you missed the meeting, here is the agenda, and recorded version and meeting notes

If you are interested in joining our clover conservation group and helping with some of the existing working groups involving research, monitoring, management, propagation, seedbanking, and fundraising for priority clover projects, please contact Tara Littlefield, tara.littlefield@ky.gov.  We will continue to provide updates on existing Trifolium projects through the ladyslipper newsletter and at the Kentucky Botanical Symposium this fall.   We will also be organizing various volunteer days this summer to help with monitoring and managing running buffalo clover, so be on the lookout for future volunteer work day announcements. 

Native clover conservation in the Bluegrass: an agronomic perspective

Jonathan O.C. Kubesch, University of Tennessee

Clovers are an odd group of plants caught between agriculture and agronomy, especially in the Bluegrass. Agronomists and cattlemen find clovers important for their nitrogen contribution and nutritive value to livestock. Horse owners fear clover for the fungal pathogen behind slobbers. Wildlife managers use them for food plots. Of the roadside clovers, most came to Kentucky with settlers (Ball et al., 2015; Bryson and DeFelice, 2009). Those red and white clovers came with the tall fescue and Kentucky bluegrass. These species play an important role in Kentucky agriculture; however, the horse parks and cattle farms have replaced the natural ecosystems in the state (Noss, 2013; Campbell, 2014; Campbell, 2010).

In addition to these introduced species, Kentucky has three prominent native clovers: annual buffalo clover, running buffalo clover, and Kentucky clover (Vincent, 2001). Although collections of the native clovers have been made across Kentucky, it is really very uncommon to find these populations unless one knows where someone else has previously found it. It is unlikely that the reader will find these species in the local park or native area.

Annual buffalo clover (Trifolium reflexum), is spread throughout most of the eastern United States. The beautiful blooms have led to its potential as a horticultural species (Quesenberry et al., 2003). Of the native clovers, the genetics of the flowering in annual buffalo clover have been the most explored: red, white, and pink flowers (Quesenberry et al., 2003). At one point, it was favored over naturalized white clover in unimproved grazing lands (Killebrew, 1898).

Running buffalo clover (Trifolium stoloniferum) is a perennial species limited to the Ohio River Valley and Missouri. Plants spread on thick runners like strawberries. The species was investigated as a potential forage in the 1990s, and has been the subject of interest for herbivory dynamics in the eastern United States. The thick seed coat requires scarification in order for the seed to germinate (Kubesch, 2018; Sustar, 2017). Hoof action has been proposed as a driver in the ecology of the species, but a general disturbance regime seems necessary for the species to persist in the landscape (Kubesch, 2018). With some sandpaper and a few hours of free time, seed can be scarified. Running buffalo clover grows readily in the greenhouse.

Running buffalo clover in the greenhouse. Photo credit: Jonathan Kubesch
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Ashland Clean-Up Day: Protecting Running Buffalo Clover

Ashland, The Henry Clay Estate in Lexington is having a clean-up day on Saturday, November 2nd from 9:00am-12:00pm. Join Heidi Braunreiter with Kentucky Nature Preserves to help pull winter-creeper from populations of running buffalo clover populations on the estate. Ashland will be providing coffee and krispy kreme donuts in the morning and Donato’s pizza at noon. Bring gloves, water, knee pads, and pruners if you have them.

Federally-endangered plant running buffalo clover

Running buffalo clover (Trifolium stoloniferum) is a federally-endangered plant that requires periodic disturbance and a partially shaded canopy. Historically, it occurred along bison trails but today it is most commonly found along forested stream terraces, trails, and lawns of old homesteads. Running buffalo clover was found at Ashland in 1989 as part of Kentucky Nature Preserves effort to survey lawns of historical homes to locate more populations. The Ashland staff have utilized mowing as a tool to create disturbance and benefit the growth of their running buffalo clover. However, an invasive vine called winter-creeper has become established in many of the running buffalo clover patches at the estate. Winter-creeper (Euonymus fortunei) is an aggresive weed that can out-compete native flora. We will be pulling winter-creeper around the patches of running buffalo clover in an effort to keep it from taking over.