Invasive Plants

Commonly found in Hillside Woods

The USDA defines an invasive species as: "an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health." Most species labeled invasive offer few "ecosystem services," i.e. food and shelter, for native fauna, and tend to aggressively take over. 

Invasive species are expanding in Hillside Woods. One reason is deer, which eat some plants but leave others. Deer give their un-liked plants a competitive advantage against other plants by clearing the forest floor for them. Another reason are the many comercial nursery plants in area yards, which escape into uncultivated areas. Birds drop their seeds wherever they go, the wind brings them, or humans and dogs track them in on their feet.

See New York State Prohibited and Regulated Invasive Plants list, 2014 for species beyond those listed here, some of which you may find in your own garden. Consider removing ecosystem-damaging plants from your yard and replacing with native (deer-resistant, if your yard is unfenced) species.

Invasive Shrubs

You will find privet,  jetbead, burning bush and Amur honeysuckle widespread above and below Vernal Pond. Burning bush has also concentrated around Sugar Pond and to its south and west. You will find Barberry, wineberry, multiflora rose and forsythia throughout the park. All of these shrubs are prevalent in Hastings area yards.


Privet grows quickly and displaces native plants. Forests containing privet tend to have less shrub diversity as well as a decreased density of herbaceous plants and trees. 

You can find more information here. 

There are privet patches all over Hillside Woods, with mature stands in the Meadow and intensive colonization between the Meadow and Vernal Pond. Many of the bushes in the Meadow have been removed by volunteers.


Native to Asia, jetbead forms a thick undergrowth which crowds out native plants and prevents the establishment of tree saplings. Additionally, it creates dense shade that impacts the native plants that require more sunlight. 

You can learn more here. 

Jetbead is found in many of the same areas in Hillside Woods as privet: mainly between the Meadow and Vernal Pond and along Edgewood Avenue.

Amur honeysuckle

Amur honeysuckle originates from China, where it grew along the Amur River, the tenth longest river in the world. In Hillside, amur honeysuckle leafs out earlier than most native plants. This creates unwanted shade, which impedes the growth of spring ephemerals and prevents the establishment of native tree seedlings. 

You can learn more here. 

Amur honeysuckle is in the Meadow, the area between the meadow and Vernal Pond, and the area northwest of Chemka Pool.

Burning bush - winged euonymus

Named after the fiery red leaves it dons in the fall, burning brush is a popular shrub for landscaping. Because it is classified as a “regulated plant species,” it is still sold in New York, despite being invasive. Burning bush is hardy and spreads quickly, dominating important native plants. 

You can learn more here. 

This shrub can be found throughout the park, with dense concentrations northwest of Chemka Pool, along the western border of Sugar Pond and along the Vernal Pond trail from Hillside School parking lot.

Japanese barberry

Japanese barberry forms dense stands that compete with native plants. Additionally, a barberry understory correlates with a 12x higher incidence of black-legged ticks, which transmit Lyme disease. Japanese barberry, if unchecked, could take over Hillside Woods' understory wall-to-wall.

You can learn more about Japanese barberry here. 

Join Hastings' Barberry Busters! We are working to survey and remove this shrub, which has been surveyed in all sections of the woods. See map.

Multiflora rose

Multiflora rose forms dense thickets, which is why in the 1930s it was used by the U.S. Soil Conservation Service as a “living fence.” A bad move, as multiflora rose has now become a prevalent invasive species, whose dense thickets choke out native plants. 

You can learn more here. 

Multiflora can be found in many parts of Hillside Woods, especially in disturbed, sunny spots like the Meadow and northwest of Chemka Pool.


Though similar, to its native cousins raspberry and blackberry, wineberry is much more aggressive. It creates dense thickets that crowd out native plants and make habitats unusable for native species. 

You can learn more here. 

However, wineberry is tasty for both humans and birds. It is found throughout Hillside Woods, especially in sunnier areas.


Forsythia isn’t considered highly invasive, but it can spread across an area quickly and is found all over Hastings. It is stoloniferous, which means that when the tip of a branch touches the ground, it can root and establish another plant. This forms a pervasive root system that is extremely difficult to remove.

You can learn more here.

Invasive Trees

Hillside Woods is 20% Norway maple. Ailanthus can be found along Edgewood and at the intersection of the red, orange and blue trails near the Meadow. Volunteers created a map of ailanthus and Norway maples along trails in our tree survey. Japanese angelica is common next to Waterfall Rock; there is also a stand in the Meadow and in a couple of other places (below Sugar Pond and on the yellow trail near Children's Village). Japanese maple can be found growing near the entrance to Chemka Pool. 

Norway Maple

The Norway maple leafs-out early, casts dark shade and has a shallow root system, which disrupts the growth of native plant species that need sunlight to grow, especially wildflowers and sugar maples. The Norway maple may also serve as a host for aphids, small insects which in large numbers will damage other plants.

You can learn more here. 

Norway maple has effectively installed itself nearly throughout Hillside Woods, forming some dense colonies in certain areas.

Ailanthus (tree of heaven)

The tree of heaven produces allelopathic chemicals, which leach into the soil and inhibit the growth of other plants. This tree also attracts the spotted lanternfly, an emerging agricultural pest devastating trees in Pennsylvania, and which is moving north. 

You can learn more here. 

Ailanthus is mostly found in the center section of the woods, between the Meadow and Edgewood Avenue. Because of its profuse seed-making, there are lots of baby trees. Because Hillside's deer are so hungry, however, they do eat ailanthus leaves, keeping the population of new trees in check.

Japanese angelica 

Japanese angelica grows aggressively and outcompetes native species. Using root suckers, it can form dense thickets over time. It's also quite thorny.

You can learn more here.

There are several stands of Japanese angelica starting to colonize Hillside Woods. Look for them in the Meadow, along the Algonquin Trail near Children's Village, in the open area west of Vernal Pond and along the west side of the trail from Chemka to Sugar Pond.

Japanese maple

Japanese maple is often recognized by its red leaves, though its leaves can actually come in a variety of colors. These trees compete with native plants and decrease the overall biodiversity of an area. 

You can learn more here.

Japanese maples are colonizing the edge of the woods near Chemka Pool driveway entrance and the walkway up to the water tower.

Invasive Vines

Porcelain berry 

Porcelain berry is easily recognized in autumn by its uniquely colored fruit, which comes in a variety of blues, purples and pinks. Though it may be aesthetically pleasing, porcelain berry can overtake an area quickly. It forms thick mats that prevent native vegetation from obtaining sunlight and water.

You can learn more here.

Porcelain berry has run amok throughout the region. It is common in the area north of the pool, in the Meadow and edges of the woods along the Saw Mill River Parkway.

Asiatic bittersweet 

Asiatic bittersweet, also known as ornamental bittersweet, is more bitter than sweet. This vine damages native plants by girdling them. The additional weight of bittersweet makes branches weaker and more likely to be damaged by storms. 

You can learn more here.

Bittersweet likes sun and is found in the Meadow and above Vernal Pond and in the tangle north of Chemka tennis courts. It's also found various random spots in the woods.

English ivy

English ivy grows across the ground and along the branches of trees. It can negatively impact tree growth by preventing foliage from obtaining sunlight and impeding photosynthesis. The added weight of the ivy makes trees more likely to lose branches during storms. English ivy also acts as a host for bacterial leaf scorch, a tree disease which causes the gradual decay of leaf tissue. 

You can learn more here.

English ivy is not common in Hillside Woods though it is present. It is common on private and public trees around Hastings.

Mile-a-minute vine

As its name suggests, mile-a-minute vine spreads quickly. In fact, it can grow up to six inches in a single day. Mile-a-minute smothers native plants by growing over them, which physically crushes them and keeps sunlight from reaching them, impeding photosynthesis. 

You can learn more here.

There are sporadic spots of mile-a-minute in Hillside Woods. It should be removed wherever it pops up. Please be on the lookout and let us know if you find any!

Asiatic wisteria

Wisteria was first introduced to the US for aesthetic purposes, coveted for it’s lilac flowers. However, the dense thickets it creates suffocate plants and girdle trees, causing tree death. This causes a gap in the tree canopy, which allows excess sunlight to reach the forest floor. 

You can learn more here.

Wisteria has trooped up and down from the former mansion where the water tower now stands, and has aggressively colonized the area north of Chemka Pool up to Sugar Pond. It has even made its way north of the pond!

Japanese honeysuckle

First introduced in the 1800s, Japanese honeysuckle is one of the most well established vines in the US. Though it may look idyllic, this fast growing vine twists around other plants and kills them by girdling them. In full sunlight, Japanese honeysuckle can grow to form large tangles, which suffocate other plants. 

You can learn more here.

Japanese honeysuckle grows in the Meadow and various areas near it plus in the tangle north of the Chemka tennis courts.

Invasive Grasses 

Invasive grasses can be especially hard to manage. There is bamboo in a couple of specific spots along the edge of Hillside Woods, while Japanese stiltgrass is common near Sugar Pond. Phragmites is colonizing the northern edge of Sugar Pond and the western side of Vernal Pond. Japanese knotweed is less common in Hillside Woods but increasingly common all over Hastings; there was once a stand next to Sugar Pond, but it seems to have been successfully eradicated. If you see this plant on your property, seek to manage it immediately.


Fast growing and sturdy, bamboo is often used as sustainable building material, though it can be used for many different things. But here in Hastings where it grows unchecked, bamboo outcompetes native plants and creates dense thickets, which are extremely difficult to remove. 

You can learn more here.  

There are at least three stand of bamboo along forest edges.

Japanese stiltgrass

Hailing from Asia, Japanese stiltgrass was first introduced to North America through its use as packing material for porcelain. Now,  Japanese stiltgrass displaces native plants and creates unwanted shade. It isn't preferred by deer, which helps it outcompete native species. 

You can learn more here.

Japanese stiltgrass is expanding throughout the woods, wherever it can get a toehold.

Common reed, or phragmites

Common reed phragmites are a prohibited species in New York State. Reed phragmites grow quickly and can easily take over a large stretch of land, with some infestations taking over hundreds of acres. 

You can learn more here.

Phragmites has overtaken the cattails at Sugar Pond and has recently swallowed all of Vernal Pond. You will also find it at the Burke Estate and other areas.

Japanese knotweed

A widespread invasive, Japanese knotweed can be found in 42 states, including New York. Japanese knotweed crowds out native plants and spreads rapidly. The ground under knotweed tends to have very few plants, leaving the soil exposed and susceptible to erosion. 

You can learn more here.

There is a lot of Japanese knotweed in Hastings, but to date, not that much in Hillside Woods. There is a stand on the east side of Sugar Pond that has recently mysteriously shrunk.

Invasive Forbs

Garlic Mustard

Sometimes used as a spice, garlic mustard forms dense stands which displace native plants and dominate resources. Additionally, garlic mustard is allelopathic, which means it produces chemicals that impede the growth of other plants. 

You can learn more here. 

Shade tolerant, ignored by deer and able to withstand the soil changes wrought by Norway maples, garlic mustard is all over Hillside Woods.


Native to Japan, shade-tolerant pachysandra is often planted to prevent soil erosion. And while the dense mats formed by pachysandra do prevent soil erosion, they also suffocate natives plants and dominate areas, creating monocultures. 

You can learn more here. 

There are some small patches in Hillside Woods, especially east of the road to Chemka Pool.


Mugwort grows to form dense stands that displace native species. The plant produces several allelopathic chemicals, which are chemicals that impede the growth of other plants. It is also a source of hay fever, which is another great reason to rid of it. 

You can learn more here. 

Mugwort grows along sunny open areas such as the path from Chemka to Sugar Pond or in the Meadow. It is sometimes mixed-in with motherwort (also invasive).


Smartweed is a particularly persistent plant, often classified as a noxious weed. There are both native and invasive varieties. Invasive smartweed grows quickly and crowds out the native species in an area, creating monocultures. 

You can learn more here.

There are various types near Vernal Pond. Smartweed likes moist soil.

Invasive Aquatic Plants


Elodea is extremely persistent and comes in many different varieties.  If allowed to grow excessively, elodea can impede water flow and affect the concentration of nutrients and dissolved oxygen in the water, which negatively impacts local wildlife. 

You can learn more here.

You will find Elodea in Sugar Pond.