In 2005, the Louisville Olmsted Parks Conservancy began a nearly four million dollar formal woodlands restoration campaign for Cherokee and Seneca Parks in reaction to woodlands degraded by hundreds of acres of noxious vines, dominant invasive exotic shrubs and noxious herbs and grasses. With chainsaws and herbicide sprayers, biologists cleared most of Cherokee Park's 409 acres and about 200 acres of Seneca Park of primarily Asian bush honeysuckle (Lonicera maackii), European buckthorn (Rhamnus cathartica), white mulberry (Morus alba), wingstem burning bush (Euonymus alatus), European privet (Ligustrum obtusifolium), Tree of heaven (Ailanthus altissima) and multiflora rose (Rosa multiflora).
The worst vines strangling regeneration of edge conditions and preventing canopy light gaps from regenerating were Oriental bittersweet (Celastrus orbiculatus), Porcelain berry (Ampelopsis brevipedunculata), English ivy (Hedera helix), wintercreeper (Euonymus fortuneii), and Japanese honeysuckle (Lonicera japonica). To lesser degrees periwinkle and crown vetch are present, though they don't seem to be colonizing new areas.
In the 2000's Cherokee Park's under story invasive shrub cover was dense enough that some areas had to be crawled through to be initially surveyed and cleared. The aftermath of exotic removal often looked like a logging operation had occurred as bucked down brush was left to biodegrade and decompose, and also reduce erosion on the bare soil left behind by four decades dominated by invasive species and exotic earthworms.
In some areas there might be only one shrub, oak, hickory, or beech sapling to get excited about in a whole acre worked for woody invasive plants, and a lot of careful follow up maintenance was required to keep out aggressive native disturbance species such as ragweed, black nightshade, blackberries, tall goldenrod, Devil's beggars ticks, horse weed, and poke berry, or wild cucumber in floodplains. Worse yet, sometimes these areas regenerate in only invasive species present in seed bank, such as buckthorn and garlic mustard, or mulberry weed which formed a lawn of seedlings in one Nettelroth south facing slope co-invaded by buckthorn and honeysuckle.
I once saw a herd of 15 white tailed deer walking the edge conditions of the park interior in fall of 2010. When an area is initially cleared, most of the sedges and rushes are eaten by rabbits or other herbivores, and deer eat the dicots, leaving whatever poisonous, thorny, or less palatable plants remain to be the first generation of succession. Coyotes have been seen as close as Seneca Golf Course and Cave Hill Cemetery, but dog leash laws provide deer a wildlife sanctuary in Cherokee Park and neighboring suburbs.
But interestingly a theory by Dr. Julian Campbell seems to have been borne out in the research of University of Louisville's, Dr. Margaret Carreiro in her bush honeysuckle experimental removal plots funded by the Environmental Protection Agency (EPA). In one of Carreiro's plots, a dominant invasive winter creeper ground cover had diminished greatly as it had been eaten, most likely by deer.
In some areas there might be only one shrub, oak, hickory, or beech sapling to get excited about in a whole acre worked for woody invasive plants, and a lot of careful follow up maintenance was required to keep out aggressive native disturbance species such as ragweed, black nightshade, blackberries, tall goldenrod, Devil's beggars ticks, horse weed, and poke berry, or wild cucumber in floodplains. Worse yet, sometimes these areas regenerate in only invasive species present in seed bank, such as buckthorn and garlic mustard, or mulberry weed which formed a lawn of seedlings in one Nettelroth south facing slope co-invaded by buckthorn and honeysuckle.
I once saw a herd of 15 white tailed deer walking the edge conditions of the park interior in fall of 2010. When an area is initially cleared, most of the sedges and rushes are eaten by rabbits or other herbivores, and deer eat the dicots, leaving whatever poisonous, thorny, or less palatable plants remain to be the first generation of succession. Coyotes have been seen as close as Seneca Golf Course and Cave Hill Cemetery, but dog leash laws provide deer a wildlife sanctuary in Cherokee Park and neighboring suburbs.
But interestingly a theory by Dr. Julian Campbell seems to have been borne out in the research of University of Louisville's, Dr. Margaret Carreiro in her bush honeysuckle experimental removal plots funded by the Environmental Protection Agency (EPA). In one of Carreiro's plots, a dominant invasive winter creeper ground cover had diminished greatly as it had been eaten, most likely by deer.
Uniquely, Cherokee Park, which was designed by the venerated landscape architect Frederick Law Olmsted has seen a great deal of historic data collection on species composition. This includes a 19th century timber survey (1891) and two floral inventories in the past century: the first by Mabel Slack for a flora published (1941), and another later by Patricia Dalton Haragan, (2006-present). The Olmsted Parks of Louisville: A Botanical Field Guide which will be available later this year. Beginning in 1891 a tree survey of the existing canopy species informed F.L. Olmsted Sr.'s General Plan for Cherokee Park completed in 1897: The Woody Plants of Kentucky, which would have included almost every native woody species to the city planted in arboretum style groupings.
Between Slack's 1941 flora and the present, the Cherokee flora has become dramatically weedier. What is impressive is the number of novel invasive species introduced to Cherokee since 1941: Johnson grass, fescue, poison hemlock, crown vetch, lesser celandine, Oriental bittersweet, porcelain berry, Princess tree, garlic mustard, hairy bitter cress, mulberry weed, roadside penny cress, Japanese stilt grass, Canada thistle, Siberian squill, Climbing yam, purple loosestrife, Teasel, wormwood, mugwort, musk thistle, sweet autumn Clematis, and now Japanese chaff flower.
Many invasive species will prefer either the Knobs or the Outer Bluegrass portions of Jefferson County/Louisville more. In the Knobs parks such as Olmsted's Iroquois Park, and especially Waverly Park and Jeffferson Memorial Forest, autumn olive (Eleagnus angustifolius) is dreadfully invasive in exactly the way privet is in Cherokee Park, requiring foliar herbiciding for management success due to the vast number of stems that can cover a plot. Princess Tree and Tree of Heaven are very problematic canopy species that seem prefer the Knobs. Tree of heaven seems to be equally happy in Cherokee Park, forming dense colonies which are carefully managed chemically so clones don't revive from root system stress.
Whereas in Cherokee Park, the Princess Tree (Paulownia tomentosa) has reached maturity and produces seeds, it is not nearly as invasive there as when growing on the acidic siltstone of the Knobs along recently logged areas, or new trail corridors.
Teasel and purple loosestrife (Lythrum salicaria), though appearing here as a few plants and there have not exploded in numbers the way they have in other settings. I killed the only teasel plant I ever found near Millvale Rd., out of a dread it might one day appear as a thicket the way giant reed does down around the Gene Snyder in drainage swales.
By the time of Mabel Slack, many desirable wildflower species had already disappeared. There is no record of blazing star, boneset, frost weed, red buckeye, New England aster, Joe pye weed, Compass plant, butterfly milkweed, cardinal flower, false indigo, wild senna, partridge pea, Dutchman's pipe, green headed coneflower, prairie coneflower, Echinacea, wild cane, green dragon, white trout lily, ginseng, golden seal, switch grass, big bluestem, eastern gamma grass, or Indian grass. The above plants are on the wish list of almost any restoration biologist familiar with Louisville's flora.
Until the era of lawnmowers and tractors, the park had been grazed by horses and sheep, and before that cows, which would have eaten whatever cane was remaining. Poisonous species may have been deleted from bridle trails, or at an earlier time by farmhands to prepare woodlands for grazing.
Many invasive species will prefer either the Knobs or the Outer Bluegrass portions of Jefferson County/Louisville more. In the Knobs parks such as Olmsted's Iroquois Park, and especially Waverly Park and Jeffferson Memorial Forest, autumn olive (Eleagnus angustifolius) is dreadfully invasive in exactly the way privet is in Cherokee Park, requiring foliar herbiciding for management success due to the vast number of stems that can cover a plot. Princess Tree and Tree of Heaven are very problematic canopy species that seem prefer the Knobs. Tree of heaven seems to be equally happy in Cherokee Park, forming dense colonies which are carefully managed chemically so clones don't revive from root system stress.
Whereas in Cherokee Park, the Princess Tree (Paulownia tomentosa) has reached maturity and produces seeds, it is not nearly as invasive there as when growing on the acidic siltstone of the Knobs along recently logged areas, or new trail corridors.
Teasel and purple loosestrife (Lythrum salicaria), though appearing here as a few plants and there have not exploded in numbers the way they have in other settings. I killed the only teasel plant I ever found near Millvale Rd., out of a dread it might one day appear as a thicket the way giant reed does down around the Gene Snyder in drainage swales.
By the time of Mabel Slack, many desirable wildflower species had already disappeared. There is no record of blazing star, boneset, frost weed, red buckeye, New England aster, Joe pye weed, Compass plant, butterfly milkweed, cardinal flower, false indigo, wild senna, partridge pea, Dutchman's pipe, green headed coneflower, prairie coneflower, Echinacea, wild cane, green dragon, white trout lily, ginseng, golden seal, switch grass, big bluestem, eastern gamma grass, or Indian grass. The above plants are on the wish list of almost any restoration biologist familiar with Louisville's flora.
Until the era of lawnmowers and tractors, the park had been grazed by horses and sheep, and before that cows, which would have eaten whatever cane was remaining. Poisonous species may have been deleted from bridle trails, or at an earlier time by farmhands to prepare woodlands for grazing.
Hickory diversity was very low even by 1941, with primarily bitternut hickory (Carya cordiformis) growing in Cherokee Park. Slack attributes this to the many uses for hickory as a hardwood used in tools, yokes, and looms. That is still the case today. Shagbark hickories are still scarce in Cherokee Park, with a small cluster growing in Barrett Hill. The three largest Carya ovata in fact grow in Olmsted's designated Barrett Hill Rd. hickory grove Juglandaceae.
In two other examples, species have stayed put where Olmsted planned for them to grow: Cross vine (Bignonia capreolata) still occurs in the BIGNONIACEAE grove near the entrance to the Dingle. And Dutchman's Pipe and Devil's Walking Stick farther up Barrett Hill both have made a resurgence through a ground cover of Winter creeper as Bush honeysuckle was removed by volunteers at the orginal boundary of the park designed by Frederick Law Olmsted Sr. Nearby also is the Olive Family Grove, OLEACEAE originally planned by Olmsted hunkers down against the Emerald Ash Borer, as an enormous green ash (Fraxinus pensylvanica) where Olmsted planned the Olive family to grow.
It appears Slack omitted the genus Ulmus and family ULMACEAE (Elm) from her flora. She does mention American elms in her foreword, and the entry for Wafer Ash (Ptelea trifoliata) is described growing at the base of an elm tree on Cochran Hill, and Dutch Elm Disease hadn't yet struck the Midwest which wouldn't happen for at least a decade or more. Though trees do succumb to the fungus, there are still a good number of slippery and American elm in Cherokee and Seneca Parks, as well as winged elms in the Knobs regions parks such as Iroquois or Waverly Park.
A modern day pest, the Emerald Ash Borer was discovered in Cherokee Park in the woods near the Baringer Overlook in late April 2013 the week before Arbor Day, less than a year after Louisville Metro Parks Foresty arborists discovered the pest in Shawnee Park on the Ohio River last year in a green ash tree, being pruned in preparation for the Arbor Day observation of April 27, 2012. A good number of blue ash (Fraxinus quadrangulata) occurs over the Park's interior limestone bluffs that overlook the Beargrass Creek corridor Cherokee Park so gracefully navigates.
In two other examples, species have stayed put where Olmsted planned for them to grow: Cross vine (Bignonia capreolata) still occurs in the BIGNONIACEAE grove near the entrance to the Dingle. And Dutchman's Pipe and Devil's Walking Stick farther up Barrett Hill both have made a resurgence through a ground cover of Winter creeper as Bush honeysuckle was removed by volunteers at the orginal boundary of the park designed by Frederick Law Olmsted Sr. Nearby also is the Olive Family Grove, OLEACEAE originally planned by Olmsted hunkers down against the Emerald Ash Borer, as an enormous green ash (Fraxinus pensylvanica) where Olmsted planned the Olive family to grow.
It appears Slack omitted the genus Ulmus and family ULMACEAE (Elm) from her flora. She does mention American elms in her foreword, and the entry for Wafer Ash (Ptelea trifoliata) is described growing at the base of an elm tree on Cochran Hill, and Dutch Elm Disease hadn't yet struck the Midwest which wouldn't happen for at least a decade or more. Though trees do succumb to the fungus, there are still a good number of slippery and American elm in Cherokee and Seneca Parks, as well as winged elms in the Knobs regions parks such as Iroquois or Waverly Park.
A modern day pest, the Emerald Ash Borer was discovered in Cherokee Park in the woods near the Baringer Overlook in late April 2013 the week before Arbor Day, less than a year after Louisville Metro Parks Foresty arborists discovered the pest in Shawnee Park on the Ohio River last year in a green ash tree, being pruned in preparation for the Arbor Day observation of April 27, 2012. A good number of blue ash (Fraxinus quadrangulata) occurs over the Park's interior limestone bluffs that overlook the Beargrass Creek corridor Cherokee Park so gracefully navigates.
At one time now endangered American chestnuts and chinquapins would have been found growing in Lousville's canopy, according to Dr. Henry McMurtrie's 1819 Florula Louisvillensis. It also lists another rarity that was down to one tree by the time of Slack: the legendary black ash (Fraxinus nigra syn. F. sambucifolia) said to have grown on the cliffs by Park Boundary Rd. above Big Rock, presumably near a seep. This same area harbors good wildflower diversity of zigzag goldenrod (Solidago flexicaulis), wild yam (Dioscorea villosa), and short's aster (Symphyotrichum shortii), and trees such as hop hornbeam (Ostrya virginiana). The removal of dense honeysuckle from the tops of these cliffs produced good results, allowing this unique environment to flourish, with mostly native vines such as trumpet creeper returning.
Some of the most interesting plants that have been seen in Cherokee Park since the woodlands restoration campaign were not even listed in 1941, including wild cane, crested coral root orchid, white trout lily, cranefly orchid, stream side orchid (non-native), green dragon (Arisaema dracontium), and wild dill (Perideridia americana) a species that is endangered in Kentucky and threatened in Ohio.
Wild dill, or as Slack calls it Eastern yampeh grows near a south facing cliff in a mixed mesophytic grove of hackberry, American beech, blue ash, chinquapin oak, sugar maple, slippery elm, and Tree of Heaven. It was not previously known to still occur in Cherokee Park.
The endangered yampeh was first seen as about a half dozen plants along a trail overgrown in Asian bush honeysuckle and Standish honeysuckle (Lonicera standishii) in 2006. Nearby was a refugia of high quality native shrubs such as American pawpaw (Asimina triloba), Blackhaw Viburnum (V. prunifolium), and bladdernut (Staphylea trifoliata). Small pockets of native bottlebrush rye (Elymus hystrix), tall American bellflower (Campanulastrum americanum), and three lobed Black eyed Susan were growing among a relatively light honeysuckle infestation. The invasive five leaved Akebia (A. quinata) had maintained an artificial open woodlands environment by climbing and girdling everything below 20 feet, even choking out invasive shrubs.
In April 2011, while doing a Sunday morning botany session I was able to photograph the Perideridia americana in flower, confirming it wasn't fennel, but instead a plant Mabel Slack had listed as rare and growing only in that one site. Atop the 40 foot cliff above the population, I found a small population of the Perideridia growing in the midst of dense bush honeysuckle and Standish honeysuckle in a small light gap. Presumably seeds from the biennial above washed down and germinated in the bare fertile soil left behind by Coast Guard Volunteers' 2009 bush honeysuckle removal. By 2011 there were dozens of plants. Now in 2013 after yet another perimeter clearing of nearby honeysuckle there are about a hundred plants.
The soil where Eastern yampeh grows is a very rocky, dolomitic gravel. Crow poison (Nothoscordum bivalve) is still rare and growing there as it was in Slack's time; and it's clear she spent a good deal of time here collecting specimens, as we were able to rediscover Alum root (Heuchera americana), purple cliff brake (Pteris atropurpureea), blunt lobed cliff fern (Woodsia obtusa) growing out of the cliff rock, tall bellflower, and bottlebrush rye all growing where Slack described them.
The next most exciting discovery was the Kentucky endangered Carolina allspice (Calycanthus floridus) found growing in a small colony in the woods north of Bonnycastle Ave. near a trail cleared of honeysuckle early on in the Woodlands Restoration campaign. An initial specimen had been found in another area of the park also in 2010, several years after this larger population had been set free. Carolina allspice typically grows in eastern Kentucky, but nevertheless we are happy to have it, and its produced a good crop of seeds one out of the past three years.
Though Cherokee Park had a population of federally endangered running buffalo clover (Trifolium stoloniferum) that went locally extinct in the mid 2000s, it wasn't listed in Slack's '41 flora. It grew near black walnuts (Juglans nigra), hackberry (Celtis occidentalis), American beech (Fagus grandifolia), black cherry (Prunus serotina), wintercreeper (Euonymus fortuneii) and Tree of heaven (Ailanthus altissima).
Other plants have gone locally extinct. Lady's tresses orchid, fall coral root orchid, skull cap (Scutellaria lateriflora), and purplish cudweed.
As a floodplain, Beargrass Creek would have harbored both buffalo and cane in pre-settlement times. The disappearance of the cane by the 1940s is no surprise, as the years of farming and free range grazing that occurred everywhere except the steepest slopes in the park interior.
As David Fothergill, former Woodlands Restoration Manager of Olmsted wrote, the high quality steep slopes presented the best restoration potential by radiating outward from these high quality areas, and performing thorough review of those relatively undisturbed areas during the early and late growing season.
As bush honeysuckle was removed the past decade, the problem of lesser celandine (Ficaria verna syn. Ranunculus ficaria) has become exponentially worse, spreading to remnant high quality uplands on Cochran Hill that Slack described as having abundant wild hyacinth (Camassia scilloides), and a population of big leaved wood sorrel (Oxalis grandis). The hyacinth is still present in abundance at this one site only and is beginning to be invaded by the lesser celandine. The scourge lesser celandine has also heavily invaded the north and eastern aspects of Beargrass Meadows regarded widely as the keystone of the Park's biodiversity, where bloodroot, nodding Trillium, Dutchman's breeches, and perfoliate bellwort still grow.
Using trails to disperse itself, the invasive lesser Celandine has spread from blanketing the floodplains every spring, and climbed the trails in seeds tracked by mountain bike tires, hikers' and runners' shoes, especially when trails are used in wet conditions. From there, the resulting new infestations usually begin growth on upland trailsides, then spread through seeds or eroded bulblets back down through dense high quality spring ephemeral populations as gravity washes them down the ravines. The celandine is still infesting high quality cliff faces and seeps harboring walking leaf fern (Camptosurus rhizophyllum), wild columbine (Aquilegia canadensis), or liverleaf (Hepatica acutiloba). The little yellow flower has also crowded out a natural population of wild geranium (Geranium maculatum) and crinkleroot which once grew downstream of bridge 1 of the Scenic Loop. As late emerging and late flowering plants are impossible to spray early in the growing season, without causing collateral damage to high quality wildlfowers, there is little that can be done. Though the earliest leaves of Ficaria verna have emerged as early as December 1, most leaves emerge in early March as soil begins to warm, and as the earliest spring ephemerals begin to emerge.
There isn't an abundance of reference wetland plants listed for Cherokee Park in 1941 as the Lake now called Willow Pond was manicured to allow fishing even at that time. Slack describes the difficulty in getting flowering specimens, and was limited to a list of only about a dozen wetland plants, including umbrella sedges, tapertip rush (Juncus acuminatus), pondweeds, duckweed, spikerush (Eleocharis obtusa), with both lizard's tail and arrowhead occurring on Beargrass Creek. Water willow was listed growing only at Ward's Mill, but has taken root in at least a half dozen shoals of Beargrass at present. Historic arrow arum (Peltandra virginica) planted by Baringer Spring in a streambed has been reduced by competition with jewel weed to only a couple plants.
The historic state threatened Pickerel Weed (Pontederia cordata) listed in 1819's Florula Louisvillensis was successfully reintroduced in a small population along rock work to the south of Willow Pond, which Slack calls Cherokee Lake. Plantings by Louisville Metro Parks Natural Areas Division at Mitchell Hill Lake and Waverly Lake have both been fairly successful at establishing emergent species such as Pickerel weed and arrowhead, and nearby grasslands have brought back species such as Indian grass, switchgrass, big bluestem, blazing star, boneset, eastern gamma grass, purple coneflower, Penstemon, and wild lupine.
With no mow management, and work on Willow Pond including runoff management with retentions and detention basins, some desirable wetland species have returned, including wool grass (Scirpus cyperinus), and sedges such as Frank's sedge (Carex frankii). These sandy rain gardens require intensive weeding of horseweed, spurges, beggar's ticks, knotweeds, amaranths, and ragweeds to maintain a high quality species palate such as Illinois bundleflower, Penstemon, blue vervain, sneezeweed, or New England Aster.
With no mow management, and work on Willow Pond including runoff management with retentions and detention basins, some desirable wetland species have returned, including wool grass (Scirpus cyperinus), and sedges such as Frank's sedge (Carex frankii). These sandy rain gardens require intensive weeding of horseweed, spurges, beggar's ticks, knotweeds, amaranths, and ragweeds to maintain a high quality species palate such as Illinois bundleflower, Penstemon, blue vervain, sneezeweed, or New England Aster.
No mow zones in Baringer Spring have had to be abandoned because of new infestations of Canada thistle (Cirsium arvense), porcelain berry (Ampelopsis brevipedunculata), or musk thistle (Carduus nutans).
The newest weed spreading in Cherokee Park is Japanese chaff flower (Achyranthes japonica). The plant was discovered in August 2011 in Seneca Park by Bowman Field, and in Cherokee Park near the famed Barnstable Brown mansion at a trail head. The chaff flower appeared to be spreading from a larger bottom land population of about 100 plants in the direction of primary mountain bike travel toward the Barrett Hill upland, where only a few scattered clusters of plants were growing trail side. A third population was identified the following year about a half mile away upslope of a high quality area where liverleaf and walking leaf fern grow.
On a portion of the former Riverwalk Trail in the River floodplain, which is now subject to a detour for the Louisville Loop (in the woods between Shawnee Golf Course and the Ohio River) flooding has deposited enough Japanese chaff flower seeds that when I first saw the dormant infestation on Christmas 2011, it had grown to 4 continuous acres of mono culture completely suppressing any other herbs or grasses, in Cottonwood, sandbar willow woods with Indigo bush and button bush. The plant sticks to one's clothing at least as bad as field parsley or beggar's ticks, and as such could easily infest a new corner of the county during a long bicycle ride.
On a portion of the former Riverwalk Trail in the River floodplain, which is now subject to a detour for the Louisville Loop (in the woods between Shawnee Golf Course and the Ohio River) flooding has deposited enough Japanese chaff flower seeds that when I first saw the dormant infestation on Christmas 2011, it had grown to 4 continuous acres of mono culture completely suppressing any other herbs or grasses, in Cottonwood, sandbar willow woods with Indigo bush and button bush. The plant sticks to one's clothing at least as bad as field parsley or beggar's ticks, and as such could easily infest a new corner of the county during a long bicycle ride.
In 2008, Japanese stilt grass (Microstegium vimineum) had been found at only one location and thought to be eradicated on the Baringer Multiuse Path, before it spread a couple miles away to the sinkholes of Barrett Hill Rd. by Chauffeur's Rest, presumably spreading in tractor tires or boots into the nearby park lawn.
In the last five years, climbing yam (Dioscorea oppositifolia) has spread from its initial discovery site with combined sewer overflow flooding, as roadside penny cress has also spread quickly across riparian zones and moist woods near the creek to encompass multiple acres previously dominated by other exotic species prior to initial clearing.
Josh Wysor is a partly self-trained botanist working as a horticulturalist for Jefferson Memorial Forest with Louisville Metro Parks Natural Areas Division, who formerly worked in the Olmsted Parks of Louisville for Olmsted Parks Conservancy from 2008 to 2010.
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