Begun in 2005, the earliest portions of the campaign heavily involved volunteers, largely focusing on Cherokee Park, and a group called the Wild Ones adopted the area for ongoing invasive species removal.
Wildflower Woods has seen a dramatic reduction in presence of woody invasive species (Bush honeysuckle, porcelain berry, Oriental bittersweet, white mulberry, privet, multiflora rose, and buckthorn) as it has seen ongoing management and repeated followup monitoring for invasive species. In the beginning, the removal effort was organic, using only mechanical methods such as weed wrenches. Later, at least by 2008, glyphosate concentrate was being used as a cut stump treatment to Asian bittersweet, privet, Asian bush honeysuckle, and the other usual suspects that are able to thrive in moderate to full shade.
Wildflower Woods has begun to see the following native ferns and spring ephemerals become common or abundant: lowland bladder fern (Cystopteris protrusa), Harbinger of spring (Erigenia bulbosa), Dutchman's breeches (Dicentra cucullaria), sessile trillium (Trillium sessile), spring beauties (Claytonia virginica), and rarely fumewort (Corydalis flava), lady fern (Athyrium filix-femina), and Green dragon (Arisaema dracontium) a close relative of Jack in the Pulpit (Arisaema triphyllum). The latter were exceedingly rare in Cherokee Park until an area of Glen Lily upstream of bridge 6 was released from Oriental bittersweet (Celastrus orbiculatus), Asian bush honeysuckle and Porcelain berry (Ampelopsis brevipedunculata) to a lesser degree. The same area harbored a healthy native population of Giant cane (Arundinaria gigantea). It only recently has developed a new invasion of Japanese chaff flower (Achyranthes japonica).
As former Woodlands Restoration Manager David Fothergill notes, Cherokee Park, which has an agricultural and pastoral legacy, pockets of high biodiversity tended to persist in areas that a) were not impacted by the 1974 Louisville tornado and b) were on slopes steep enough, grazing animals would have been either kept out, or would have found less desirable for woodland grazing.
According to expert native plants botanist Kevin Tungesvick of Spence Restoration Nursery in central Indiana, areas with a legacy of heavy agricultural use, are often doomed to low floristic quality indices (FQA) unless managers resort to extensive replanting and careful sustained followup management to usher these reintroduced communities into a healthy self-sustaining state.
This has been the case in most areas of Cherokee Park, which have no trouble growing weedy native plants such as American burnweed (Erechtites hieracifolia), horseweed (Conyza canadensis), pokeberry (Phytolacca americana), Devil's beggars ticks (Bidens frondosa), white snakeroot (Ageratina altissima), blackberry (Rubus occidentalis), tall goldenrod (Solidago altissima), or naturalized non-natives including the noxious ground ivy (Glechoma hederacea), common chickweed (Stellaria media), or stickywilly (Galium aparine).
This has been the case in most areas of Cherokee Park, which have no trouble growing weedy native plants such as American burnweed (Erechtites hieracifolia), horseweed (Conyza canadensis), pokeberry (Phytolacca americana), Devil's beggars ticks (Bidens frondosa), white snakeroot (Ageratina altissima), blackberry (Rubus occidentalis), tall goldenrod (Solidago altissima), or naturalized non-natives including the noxious ground ivy (Glechoma hederacea), common chickweed (Stellaria media), or stickywilly (Galium aparine).
As noted Kentucky botanist Patricia Dalton Haragan conducted floristic surveys for the Conservancy in the mid 2000s, updating the 70 year old research of an earlier Louisville botanist Mabel Slack, a clear picture of the problem of invasive species emerged. Many new invasive species had arrived since Slack's 1941 floristic survey, as other species once anywhere from rare or infrequent to common had completely disappeared.
The following "invasive" species were absent (yet to be introduced) from Slack's 1941 Cherokee Park: Multiflora Rose (Rosa multiflora), Asian bush honeysuckle (Lonicera maackii), Japanese stilt grass (Microstegium vimineum), Porcelain berry (Ampelopsis brevipedunculata), climbing yam (Dioscorea oppositifolia), Garlic mustard (Alliaria petiolata), Johnson grass (Sorghum halepense), lesser celandine (Ficaria verna syn. Ranunculus ficaria), Roadside pennycress (Thlaspi alliaceum), Japanese chaff flower (Achyranthes japonica), Canada thistle (Cirsium arvense), musk thistle (Carduus nutans), teasel (Dipsacus fullonum).
What already was "invasive" then was Japanese honeysuckle vine (Lonicera japonica). Winter creeper and five leaved Akebia were still well behaved, though present. Periwinkle, was probably a full ground cover where planted. Chinese silver grass and autumn olive, though present 70 years ago, never have become a major threat to Cherokee Park.
The following "invasive" species were absent (yet to be introduced) from Slack's 1941 Cherokee Park: Multiflora Rose (Rosa multiflora), Asian bush honeysuckle (Lonicera maackii), Japanese stilt grass (Microstegium vimineum), Porcelain berry (Ampelopsis brevipedunculata), climbing yam (Dioscorea oppositifolia), Garlic mustard (Alliaria petiolata), Johnson grass (Sorghum halepense), lesser celandine (Ficaria verna syn. Ranunculus ficaria), Roadside pennycress (Thlaspi alliaceum), Japanese chaff flower (Achyranthes japonica), Canada thistle (Cirsium arvense), musk thistle (Carduus nutans), teasel (Dipsacus fullonum).
What already was "invasive" then was Japanese honeysuckle vine (Lonicera japonica). Winter creeper and five leaved Akebia were still well behaved, though present. Periwinkle, was probably a full ground cover where planted. Chinese silver grass and autumn olive, though present 70 years ago, never have become a major threat to Cherokee Park.
In the instances that management efforts were focused on high quality management areas, with followup efforts radiating outward from core areas of ecological integrity, some notable successes occurred. A small but healthy population of White lettuce (Prenanthes alba) was rediscovered by myself early this spring, and confirmed by Haragan on a hillside known colloquially to Olmsted's field crew as Haragan Hill. It is located in an area that is now closed for "resting" along an old trail in a blue ash, American basswood, and chinquapin overstory. White lettuce was listed as rare by Slack in 1941.
Another recovery began at least as early as 2008, when Eastern yampeh (wild dill, wild parsley) or Perideridia americana syn. Eulophus americanus (Slack) was first seen by Olmsted Conservancy staff, and later conclusively identified by myself and confirmed by Pat Haragan in 2013. I photographed it in flower in April 2011, suspecting it may be the rare Eastern yampeh, listed as threatened in the state of Kentucky. This plant was also listed as rare by Slack in 1941.
The Eastern yampeh is found growing in a blue ash, chinquapin oak, American beech slope, with rocky dolomitic limestone soils, and a healthy community of understory plants including American bladdernut, black haw Viburnum, Ohio buckeye, and Pawpaw. The primary dominant species had been Asian bush honeysuckle (Lonicera maackii), and Standish honeysuckle (Lonicera standishii) which is easily mistaken for Fragrant honeysuckle, and flowers as early as February, producing an early spring fruit resembling a heart. These were the predominant overstory of this south facing rocky slope.
This population has expanded in the aftermath of honeysuckle removal, and a 2013 population survey by myself suggests that it had survived atop a 40 foot limestone cliff, producing seeds which likely washed down to the trail below, and germinated in the bare soil conditions left behind in the aftermath of honeysuckle removal.
As Joe Manning, zone steward of the area for Olmsted Parks Conservancy wrote in a 2009 management plan for the Glen Lily area, it is the gem of biodiversity of Cherokee Park. During the ongoing management the area has seen (2009-2013) the discovery or rediscovery of Crested coral root orchid (Hexalectris spicata), alum root (Heuchera americana), purple cliff brake (Pellaea atropurpurea), and blunt lobed cliff fern (Woodsia obtusa) all locally rare plants.
The coral root orchid was discovered by Pat Haragan as early as 2006, and was originally growing in a ground cover of non-native five leaved Akebia (A. quinata), which probably had kept the site from growing up in saplings and seedlings, helping to maintain open woods conditions favored by the orchid.
Since then the ground cover was managed with dormant season foliar applications of 6% glyphosate in late fall 2010. The population has been slowly diminishing during this management phase, whether due to drought conditions in 2011 and 2012, or perhaps collateral damage to the mychorrhizal horizon of soil from which Hexalectris spicata depends upon for nutrients. Haragan describes the population as over 100 plants in 2008, and this has been in steady decline in the period of 2010-2013, with a total of 65 stems counted during growing season of July-Sept. by myself.
Dozens of new stems have, however appeared in an area managed by Conservancy staff in 2012 and 2013, which saw Asian bush honeysuckle shrub removal, and cut stump treatment with a 25%-50% glyphosate mix.
Notably, this area has begun to develop a deeper leaf layer since that removal. The orchid, according to Illinois Urbana-Champagne researcher Stephen Hill, prefers rich, well drained humus, like that found at the Glen Lily site.
Hill does write that the preferred management method for this rare orchid is woodland burning, (presumably during dormant season). There are clearly obstacles to this management method in a highly regulated suburban city setting, though the cliffs above the area would prevent fire from spreading uphill to nearby properties.
Over the past five years the orchid has also been observed growing out of a small dense ground cover of wintercreeper (Euonymus fortuneii), though never in numbers more than two orchids, and never in nearly the density it has been able to grow through the once abundant ground cover of five leaved Akebia.
