The Accotink Gorge

  Read about our Accotink Gorge Wisteria Workdays

July 7, 2015 - Concerned naturalist guides survey of the exceptional flora of the Accotink Gorge and issues an urgent call to action:

What is the Accotink Gorge?

The Accotink Gorge is truly one of the most biodiverse locations I have ever had the privilege of exploring, especially given its small size and proximity to development. However, if urgent action to remove Wisteria sinensis (Chinese wisteria) vines which are rapidly killing its canopy trees is not taken soon, all of this will be irrevocably lost. Many beautiful native wildflowers are currently in bloom and the area is teeming with pollinators and birds. It is not too late to save this oasis, but it will be soon.

I am hoping to get the word out to people who will be able to engage in some heavy duty invasive species removal work which will involve cutting down large Wisteria sinensis vines and hauling them away from the site. This may necessitate the use of special equipment. There are many wild areas in this region which are overrun with invasives, but this is one in which what could be saved by prompt removal is particularly amazing.

In the interest of preserving the unique biodiversity of the site, despite the fact that it is the fertile floodplain forest that is currently most seriously infested, the high dry rocky oak hickory forest, which is just starting to be invaded, is where the Wisteria sinensis removal should begin, as it contains the most uncommon species, and unlike the floodplain habitat, which has evolved in a state of continual disturbance, and should regenerate well, the ancient plant communities on the higher slopes, and the fragile soils which support them, once lost, will be lost forever.

In Accotink Stream Valley Park, in the southern portion of Accotink Gorge, exists one of the more diverse examples of oak hickory heath forest in the entire Fairfax County park system, where native trees and shrubs coexist with native grasses such as Danthonia spicata (Poverty grass), Piptochaetium avenaceum (Blackseed needlegrass), and Melica mutica (Twoflower melicgrass), as well as flowering herbaceous species such as Clitoria mariana (Butterfly pea), Aureolaria virginica (Downy false foxglove), Silene caroliniana (Wild pink), Symphyotrichum patens (Late purple aster), and Asclepias variegate (Variegated milkweed). There are also some extremely steep slopes in the oak hickory forest, with particularly acidic soil, where the Wisteria has been unable to invade, but the understory in these sections consists largely of Kalmia latifolia (Mountain laurel), and is not particularly species diverse.

Throughout Accotink Gorge, the priority should be saving the canopy trees that are still salvageable, starting at the higher elevations, once that is done, the understory can be dealt with. Based on the spring ephemerals that I observed before the Wisteria leafed out, the native floodplain forest understory vegetation has not died out yet, it is merely being suppressed by the Wisteria growing on top of it, and it should regenerate fast and well once the Wisteria is removed. The meadow created by the powerline cut which bisects this area is also quite biodiverse, providing habitat for sun loving native species including milkweeds and many grasses, whose populations have declined in natural areas due to fire suppression, however it is a distant last on the priority list for Wisteria removal. There are invasive species other than Wisteria in Accotink Gorge, but it is the Wisteria that is killing the canopy trees, and until that is dealt with, worrying about anything else is just a distraction.

I fell in love with this place as soon as I set foot there, and I hope to share this experience with other people who might be able to make a difference to save it. Despite seeing how fast the Wisteria has advanced over the course of just one year, and the fact that it has begun to actually topple over canopy trees, creating a nearly impenetrable thicket in some areas, I truly believe that it is not too late. The only plants that should be removed from this place are invasive species. I have come upon evidence of the poaching of large colonies of Epigaea repens (Ground laurel) from this location, and I want to make it very clear to anyone who may be misguided on the issue that removing native plants from an embattled natural area such as this is not a "rescue". Please leave all the native plants where they are so that they can revegetate the areas that will be disturbed in the process of Wisteria removal. Many of the species present in this very special area are only present in very small populations, for instance, there is only one Ionactis linariifolia (Flax-leaf ankle-aster) so, at least until the Wisteria has been removed, and populations of these native species have had a chance to recover, it is not even appropriate to collect a voucher specimen.

If you know anyone who would be able to help organize invasives removal work, please forward this to them and bring them into the discussion. It is my hope that this event will catalyze the community to come together and save this very special place for future generations.

Fritz Flohr Reynolds - July 7, 2015

Great Falls of the Accotink, at the confluence with Field Lark Branch

Flora photos here       7-7-15 Survey photos here
               Our PowerPoint presentation

Native Flora Species observed so far in the Accotink Gorge, with photolinks:
Acer negundo (Boxelder maple)
Alnus serrulata Smooth alder
Amelanchier canadensis Shadbush serviceberry
Amphicarpaea bracteata Hog-peanut
Andropogon virginicus Broomsedge
Anemone quinquefolia Wood anemone
Antennaria plantaginifolia Plantain-leaved pussytoes, being eaten by Vanessa virginiensis caterpillar (American painted lady)
Antennaria solitaria Singlehead pussytoes
Apios americana American groundnut
Aralia spinosa Devil's Walking-stick
Asclepias amplexicaulis Sand milkweed
Asclepias incarnata Swamp milkweed
Asclepias tuberosa Butterfly weed
Asclepias variegata Variegated milkweed
Asclepias viridiflora Green milkweed
Asplenium platyneuron Ebony spleenwort
Aureolaria virginica Downy false foxglove
Baptisia tinctoria Yellow wild indigo
Bidens aristosa Bearded beggarticks
Campsis radicans Trumpet vine
Cardamine angustata Slender Toothwort
Carpinus caroliniana Hornbeam
Carex crinita Fringed sedge
Carex pensylvanica Pennsylvania sedge
Carya sp. (Hickories, various)
Chamaecrista fasciculata Partridge pea
Chelone glabra White turtlehead
Chionanthus virginicus Fringe tree
Chrysopsis mariana Maryland goldenaster
Cirsium discolor Field thistle
Claytonia virginica Spring beauty
Clitoria mariana Butterfly pea
Coleataenia anceps Beaked panicgrass
Collinsonia canadensis Richweed
Corydalis flavula Yellow Corydalis
Coreopsis verticillata Threadleaf coreopsis
Cornus florida Flowering dogwood
Crataegus pruinosa Waxyfruit hawthorn
Cunila origanoides Dittany
Cyperus echinatus Globe flatsedge
Cyperus esculentus Yellow nutsedge
Cyperus strigosus Strawcolored flatsedge
Danthonia spicata Poverty grass
Dendrolycopodium obscurum Indian Cucumber-root
Desmodium rotundifolium Low tick trefoil
Dichanthelium clandestinum Deertongue grass
Dichanthelium commutatum Variable panicgrass
Dichanthelium dichotomum Cypress panicgrass
Dichanthelium scoparium Velvety panicgrass
Dichanthelium sphaerocarpon Roundseed panicgrass
Diodia teres Common buttonweed
Diospyros virginiana American persimmon
Doellingeria infirma Cornel-leaf whitetop aster
Elymus glabriflorus Southeastern wildrye
Elymus hystrix Bottlebrush grass
Elymus virginicus Virginia wildrye
Endodeca serpentaria Virginia snakeroot
Epigaea repens Mayflower
Eragrostis spectabilis Purple love grass
Erythronium americanum Yellow trout-lily
Eubotrys racemosus Swamp doghobble
Euonymus americana Strawberry bush
Eupatorium hyssopifolium Hyssopleaf thoroughwort
Eupatorium rotundifolium Roundleaf thoroughwort
Eupatorium sessilifolium Upland boneset
Euphorbia corollata Flowering spurge
Eurybia divaricata White wood aster
Euthamia graminifolia Grass-leaved goldenrod
Eutrochium sp. Joe-Pye weed
Festuca subverticillata Nodding fescue
Fraxinus pennsylvanica Green ash
Galactia volubilis Downy milkpea
Gamochaeta purpurea Purple cudweed
Hamamelis virginiana American witch hazel
Helianthus divaricatus Woodland sunflower
Heliopsis helianthoides Smooth Oxeye
Heuchera americana American alum-root
Hieracium venosum Rattlesnake hawkweed
Houstonia caerulea Quaker ladies
Houstonia purpurea Venus' pride
Hylodesmum nudiflorum Bare-stemmed tick-trefoil
Hypericum gentianoides Pineweed
Hypericum hypericoides St. Andrew's cross
Hypericum perforatum Common St. John's-wort
Ilex opaca American holly
Ionactis linariifolia Flax-leaf ankle-aster
Ipomoea pandurata Wild sweet potato
Justicia americana American water-willow
Kalmia latifolia Mountain laurel
Krigia virginica Virginia dwarf-dandelion
Lactuca hirsuta Hairy lettuce
Lechea sp. Pinweed family
Linum sp. Flax family
Lobelia cardinalis Cardinal flower
Lobelia inflata Indian tobacco
Lysimachia ciliata Fringed loosestrife
Lysimachia quadrifolia Whorled loosestrife
Maianthemum racemosum False Solomon's-seal
Medeola virginiana Common ground-pine clubmoss
Mertensia virginica Virginia bluebells
Melica mutica Twoflower melicgrass
Micranthes virginiensis Early saxifrage
Mitchella repens Partridgeberry
Monarda fistulosa Wild bergamot
Nuttallanthus canadensis Blue Toadflax
Nyssa sylvatica Black gum
Oxalis violacea Violet Wood-sorrel
Packera aurea Golden Ragwort
Panax trifolius Dwarf ginseng
Panicum virgatum Switchgrass
Paspalum laeve Field paspalum
Passiflora incarnata Purple passionflower
Passiflora lutea Yellow passionflower
Phlox maculata Meadow Phlox
Physocarpus opulifolius Atlantic nine-bark
Piptochaetium avenaceum Blackseed needlegrass
Platanus occidentalis Sycamore
Polygala mariana Maryland Milkwort
Polygonatum biflorum Giant Solomon's seal
Polypodium virginianum Common Rock Polypody
Pteridium aquilinum Bracken fern
Prenanthes serpentaria Lion's-foot
Pycnanthemum tenuifolium Narrowleaf mountainmint
Quercus alba White oak
Rhododendron periclymenoides Pinxterbloom azalea
Rhus copallinum Winged sumac
Rosa carolina Carolina rose
Rubus flagellaris Common Dewberry
Salvia lyrata Lyre-leaved sage
Sanguinaria canadensis Bloodroot
Sassafras albidum Sassafras
Scirpus cyperinus Woolgrass
Scutellaria elliptica Hairy skullcap
Scutellaria integrifolia Helmet Skullcap
Senna sp. Senna family
Sericocarpus asteroides Toothed white-topped aster
Silene antirrhina Sleepy catchfly
Silene caroliniana Wild pink
Silene stellata Starry campion
Smilax rotundifolia Common Greenbrier
Solidago caesia Blue-stem goldenrod
Solidago juncea Early goldenrod
Stellaria pubera Star chickweed
Symphyotrichum patens Late purple aster
Symphyotrichum prenanthoides Crooked-stem aster
Tephrosia virginiana Goat's rue
Teucrium canadense Canada Germander
Thalictrum pubescens Tall meadow-rue
Tiarella cordifolia Foamflower
Trichostema dichotomum Forked bluecurls
Tridens flavus Purpletop
Tripsacum dactyloides Eastern gamagrass
Uvularia sessilifolia Small bellwort
Vaccinium sp. Blueberry family
Verbena urticifolia White vervain
Verbesina alternifolia Wingstem
Vernonia glauca Upland Ironweed
Viburnum acerifolium Mapleleaf viburnum
Viburnum prunifolium Black haw viburnum
Viola blanda Sweet white violet
Viola sagittata Arrow-leaved violet