There are 133 species and subspecies of deciduous and evergreen trees native to
the Commonwealth of Pennsylvania. Native plants are part of our natural heritage
and future. William Penn described the forests of Pennsylvania as “the natural produce
of the country.”
Using native species in landscape and wildlife plantings provide many ecological
benefits which introduced plants may not.
Native plants provide diverse communities that support wildlife populations throughout
the year, while many exotic plants have little or no wildlife value and displace
the native species.
Native plants, used for landscaping purposes, are often more adaptable to natural
environments, and can have greater resistance to droughts, insects and diseases
once they are established on the site.
- Native plants are often more functional in the landscape, providing stream bank
stabilization, erosion control, climate control, and wildlife habitat.
The following websites can assist you in learn more about native trees and plants.
Learn how to identify the Common Trees of Pennsylvania – New 2011 Edition!
Landscaping with Native Plants Brochure
Plant Information: Morris Arboretum of the University of Pennsylvania
Pennsylvania Native Plant Society
Bowman’s Hill Wildflower Preserve
Native Plant Society of New Jersery
Delaware Native Plant Society
Maryland Native Plant Society
Exotic Invasive Plants
Drive down any road in the region and you will probably find non-native plant species
beginning to invade our forests, stream corridors, meadows, and yes, even the ornamental
landscapes at your home. When was the last time you walked your property and wondered
why there seems to be plants that are taking over? Your property may already have
been invaded by an “exotic invasive” plant or you might have even accidentally planted
some in your landscape that will soon escape and invade a nearby forest or stream.
As good stewards we need to become more aware of the impact these non-native invasive
species have on our local environment and learn to identify and properly control
these species before they completely take over an area.
What is an “Exotic Invasive Plant”?
It is really just another name for a noxious environmental weed pest that was introduced
from other continents and has escaped cultivation causing serious harm to native
habitats for insects and wildlife. Before you start tearing out all your landscape
plants, you must know that NOT all non-native plants are invasive and there are
some native plants that have a tendency to become invasive (especially on disturbed
sites). In order for a plant to be considered “invasive”, it usually grows aggressively
(on various sites and growing conditions), spreads quickly (by seed, rhizomes, or
cuttings), lacks natural predators, pathogens and parasites, and displaces native
Does it really matter what is growing on my property?
Researchers at Cornell University and elsewhere have estimated that “Exotic Invasive
Species” (plants, insects, and animals) are costing the United States more than
$138 billion each year, due to their economic impact on agriculture, forestry, fisheries,
wildlife, ornamental landscapes, waterways, and the Nation’s other natural resources.
The cost and losses associated with plant, pests and weeds was estimated at $80
billion per year. Invasive species impair biological diversity by causing population
declines, species extinctions, shifts in predator-prey dynamics, shifts in species
niches, changes in habitat, and reductions in ecosystem complexity.
Websites to visit for more information about identifying and controlling Exotic
Pennsylvania DCNR Wild Plant Program
PA Roadside Vegetation Research at Penn State University
BioControl of Non-Indigenous Plant Species
DCNR Invasive Plant Tutorial
DCNR Invasive Plants
So What Can Be Done to Prevent and Control “Exotic Invasives”?
- Become Educated
: Get educated on what invasive species look like and educate others! Contact your
local Penn State Cooperative Extension Office in your county and request information
(fact sheets) about specific invasive species or bring them plant samples for identification.
- Don’t plant species that are considered invasives
: Avoid using garden plants from other regions whose invasive potential is poorly
understood. In addition to potential threats to natural areas, some exotics
become pests in carefully managed landscapes and gardens. Get a copy of DCNR’s Invasive
Species brochure that lists plants that should not be planted.
- Discover alternatives in your landscape
: Promote responsible gardening by learning about the plants around you. Identify
brochures and local information. When considering natives as an alternative, buy
nursery propagated plant material. Never dig or buy plants that have been dug in
the wild. Get a copy of DCNR’s Native Plants brochure that lists species that could
- Remove invasive exotics
: Remove from your landscape and replace them with native plants or non-invasive
exotics. In order to properly control many invasives plants, some herbicide use
is required. For some, pulling or cutting only spread them more. The impact of leaving
an exotic invasive to take over a site far outways the use of herbicides to remove
- Minimize landscape disturbance
: Promote healthy native plant communities. Invasives thrive on bare soil and disturbed
ground where the native plant community has been displaced.
- Limit use of fertilizers
: Native plants are adapted to naturally low nutrient levels. For soil fertility,
try using organic slow-decomposing compost and mulches.
- Clean boats and trailers of all aquatic plants
: While some species of invasive aquatics are known to be present in an area, others
continue to move in,Boats, bait buckets, etc are important vectors for moving species
around, especially zebra mussels.
- Avoid the release of unused bait and or aquariums
: Do not release unused fishing bait or discard aquarium plants or animals into
lakes or streams.
: Remove invasive exotics before they are a problem, when densities are low. Scout
annually for invasives. Do not allow them to go to seed. Learn how to best control
- Get involved in local or regional volunteer weed removal programs - i.e.,
Weed Warriors, etc.