Problematic Plant Monitoring at Hopewell Culture National Historical Park

Amur honeysuckle is the most commonly encountered problematic plant at Hopewell Culture National Historical Park, Chillicothe, Ohio.

NPS

What Are Problematic Plants?

Sometimes plants grow in places where they don't naturally occur and some plants can cause damage to ecosystems and even harm people. Exotic plants are nonnative species that are typically introduced into an ecosystem by human actions, whether intentional or not. Invasive plants are exotic species that cause ecological or economic harm. Pest plants, which can be native species, interfere with specific management objectives and are sometimes called weeds. We refer to the collection of exotic, invasive, and pest plants as problematic plants.

Problematic Plant Management

National parks spend a lot of time trying to remove or control problematic plants to protect native plant and animal communities and visitors at parks. When a plant species is impairing park resources, managers are required to control the plant. They use five criteria to decide what other problematic plants they will control: the origin of the species, prudence of the action, feasibility of controlling the plant, the harm or impact that the plant causes, and the harm that removal of the plant could cause. Managers use environmental assessments, the professional judgment of experts, and scientific research to make these decisions. They also consult with regulating agencies and the public.

We searched for problematic plants around the cultural sites at Hopewell Culture National Historical Park. The average size of these individual, numbered search units is 2.0 acres.

NPS

Plant Surveys

Park managers have to know where problematic plants are to control them. The Heartland Inventory and Monitoring Network collects information on the cover (a measure of how much ground is covered by the plant), distribution, and location of problematic plants at Hopewell Culture National Historical Park. We surveyed the park in 2008, 2011, 2015, and 2019. Managers can develop management actions and track the success of their control efforts using the information from our surveys. We use an early detection watch list and a park-established watch list to search for problematic plants. Early detection species are plants that have not been detected on the park before but have the potential to grow there. Plants on the park-established watch list have been found in the park during previous surveys.

Problematic Plants on the Park

Since 2008, we have identified 51 problematic plants at Hopewell Culture National Historical Park; 37 of these species were found in 2019. Autumn olive, tall fescue, Amur honeysuckle, and Japanese honeysuckle occupied more than 10 acres, which makes them more difficult to control. These two honeysuckles, garlic mustard and multiflora rose are well-established in the park and were found in more than half of the areas searched. In 2008, we did not find any Japanese stiltgrass in the park, and in 2019, it was growing on more than a quarter of the areas we searched. It is a plant that grows rapidly, so It will likely spread further within the forests. Because there are so many problematic plants on the park, managers will have to prioritize their control efforts.

Problematic Plant Species at Hopewell Culture National Historical Park (2008–2019)

Problematic plants found at Hopewell Culture National Historical Park (2008–2019). An asterisk (*) indicates that the species was not found in 2019 surveys.

Common Name	Scientific Name
tree of heaven	Ailanthus altissima
silktree*	Albizia julibrissin
garlic mustard	Alliaria petiolata
lesser burdock*	Arctium minus
Japanese barberry	Berberis thunbergii
smooth brome	Bromus inermis
bald brome, spiked brome	Bromus racemosus
poverty brome*	Bromus sterilis
cheatgrass*	Bromus tectorum
Oriental bittersweet	Celastrus orbiculatus
Canada thistle	Cirsium arvense
bull thistle	Cirsium vulgare
Queen Anne's lace	Daucus carota
Fuller's teasel	Dipsacus fullonum
autumn olive	Elaeagnus umbellata
burningbush, winged euonymus	Euonymus alatus
winter creeper	Euonymus fortunei
glossy buckthorn	Frangula alnus
ground ivy	Glechoma hederacea
orange daylily*	Hemerocallis fulva
dames rocket*	Hesperis matronalis
common motherwort*	Leonurus cardiaca
European privet	Ligustrum vulgare
Japanese honeysuckle	Lonicera japonica
Amur honeysuckle	Lonicera maackii
Morrow's honeysuckle	Lonicera morrowii
Tatarian honeysuckle*	Lonicera tatarica
bush honeysuckle sp.* (Amur-Morrow's-Tartarian complex)	Lonicera maackii/morrowii/tatarica
creeping jenny	Lysimachia nummularia
yellow sweetclover	Melilotus officinalis
Japanese stiltgrass/Nepalese browntop	Microstegium vimineum
white mulberry	Morus alba
wild parsnip	Pastinaca sativa
reed canarygrass*	Phalaris arundinacea
Canada/Kentucky bluegrass complex	Poa compressa/pratensis
Kentucky bluegrass	Poa pratensis
Japanese knotweed*	Polygonum cuspidatum
sulphur cinquefoil*	Potentilla recta
Mahaleb cherry*	Prunus mahaleb
Callery pear	Pyrus calleryana
black locust	Robinia pseudoacacia
multiflora rose	Rosa multiflora
curly dock	Rumex crispus
bouncingbet	Saponaria officinalis
tall fescue	Schedonorus arundinaceus
crownvetch	Securigera varia
Johnsongrass	Sorghum halepense
spreading hedgeparsley	Torilis arvensis
Siberian elm*	Ulmus pumila
common mullein	Verbascum thapsus
common periwinkle	Vinca minor

Japanese stiltgrass most likely arrived in North America from Asia as packing material for porcelain in the early 1900s. The seeds spread very easily by wildlife and humans and in water.

Alicia Lafever/NPS

Species Spotlight: Japanese Stiltgrass

Japanese stiltgrass (Microstegium vimineum) invades forests, stream banks, fields, and lawns and is one of the most damaging invasive plants in the U.S. Each plant can produce up to 1,000 seeds per year and the seeds can still germinate after five years in the soil. It spreads very quickly and grows in dense stands that prevent native plants from growing. These characteristics make it more difficult to control than other problematic plant species. Japanese stiltgrass is now found across the eastern United States and as far west as Texas. Focused control of this plant at Arkansas Post National Memorial is very important for protecting park ecosystems.

For More Information

Read the Full Report.

Check back later for updates. We will update this page each year as we gather information.

Visit the Heartland Inventory & Monitoring Network website.