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Stop the Spread

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Knowledge is Power. Educate yourself and others, so together we can have a positive impact on the livelihood  and longevity of our region. 
Stop the Spread Top

Invasive Species

We Need Your Help!

Invasive species, often referred to as “unwanted hitchhikers,” threaten our lake, home properties and the surrounding watershed. Invasive species are non-native plants, animals or insects that cause harm to the environment and/or people’s health. One of the biggest threats to our watershed is the Hemlock Woolly Adelgid. If not controlled, most of our region’s hemlocks will be destroyed within 10 years! The rate and risk of invasives over the years is increasing due to human population growth, environmental alteration, and movement of people and equipment.


Invasives have no upside and numerous downsides:

  • Drag property values down

  • Impede access to recreational uses of the lake, such as swimming and boating

  • Increase the potential for erosion

  • Adversely affect the cold-water fishery

  • Destroy trees and other plants

Through surveillance, harvesting, boat washing stations and education, ESSLA is striving to protect the Schroon Lake watershed from the spread and negative impact of invasive species. But we can’t do it without you! Whether you’re a resident or visitor, please help us fight this battle. Learn how to identify the various species. Be on the lookout while on the lake, walking, hiking or working on your property. And please contact us at if you spot something!



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Curly Leaf Pondweed

Fully submersed aquatic plant. Has a very distinctive appearance with crinkled leaves resembling wavy lasagna noodles. They are approximately 1/2" wide and 2-3 inches long. The leaves are arranged alternately around the stem and are finely toothed, becoming denser at the end of branches. Plant dies in July and seeds drop to bottom sediment. Forms dense mats that inhibit growth of native species and impede recreational activities.


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Harmful Algal Blooms

Algae found along shore lines or in open water, its blooms often look like thick scum or paint in differing colors on the surface of the water.  They can be found along shore lines or in open water and last anywhere from hours to weeks. HABs can release dangerous toxins that are public health concerns. Avoid swimming, boating, otherwise recreating in or drinking water with a bloom.  In NY, they are increasing in frequency and in Sept. 2020, Schroon had a bloom that was confirmed as a HAB by NYS.


Aquatic Invasive Species found in Schroon Lake:                                      Euras

Eurasion Milfoil

An underwater perennial grass that can reach heights of 20 feet, forming dense mats near surface. Usually 12-21 leaflet pairs per leaf.  Leaflets are closely spaced.  Leaves collapse around stem when out of water. Reddish stem that branches near surface. Plant fragments easily break off and can be transported from lake to lake via boats and trailers, starting new populations, degrading habitat and reducing recreational access. Once established, it spreads easily, grows quickly and is difficult to remove. The densely growing grass entangles boat propellers, interferes with swimming and fishing and negatively impacts the natural aquatic habitat.  




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Bush Honeysuckles

An ornamental woody shrub which grows well in full or partial sun. Leaves are oval, opposite with smooth edges. Grey Stems are hollow. It flowers in May / June with pink, white or yellow blooms followed by clusters of red, pink or orange berries in late summer. Spreads long distances into forests by birds dispersing fruit & seeds.  Six-15’ feet tall and 20+ feet wide, it forms dense thickets, crowding out native plants and inhibiting forest regeneration.


Garlic Mustard

Garlic Mustard

A biennial herb averaging 3+ feet that emerges in early spring. It begins as an inconspicuous first year plant (rosette) that looks similar to wild violets having triangular somewhat heart shaped leaves that have coarsely toothed margins and wrinkled leaf surfaces. 2nd year - multiple stems with a tall flower spike and four petal white flowers developing into slender pods bursting with tiny round seeds and sharp-toothed leaves.  Leaves & single stems produce distinctive garlic odor when crushed. A native to Europe, Asia & NW Africa, it invades moist forests, wooded streambanks, roadsides and trail edges where it disrupts normal plant – fungi relationships resulting in elimination of native species. Its roots exude compounds that alter soil chemistry to favor its survival at the expense of other species. Difficult to control once established.  


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Japanese Barberry

An ornamental bush from Japan which spreads rapidly, forms dense thickets and crowds out native understory plants.  A dense deciduous spiny shrub, 2-8 ft tall with small oval to spoon shaped green, yellow or purple leaves with smooth margins that turn red in fall. It has tiny pale yellow dangling flowers that hang in clusters of 2-4 nodes that bloom in April and May.  Arching branches are grey with sharp thorns. Berries-bright red oval shaped. Grows well in bright sun or shade. Unpalatable for local wildlife, but serves as a deer tick habitat and is implicated in the spread of Lyme Disease.



Oriental Asian Bittersweet

An aggressive perennial woody vine from Asia. It has elliptic alternating leaves with serrated edges, spiraling around a stem. Stems vary in diameter and can be up to 6+ inches.  Prefers open sun along forest edges. Flowers May – early June with bright reddish-orange fruit in fall.  Can be distinguished from native American bittersweet which has flowers and fruit at the end of its branches.  Competes for sunlight, growing up to 60 ft. It chokes out native plants and trees by smothering them with its dense foliage and strangling stems and trunks.



Spongy Moth

Insect from Europe. Caterpillars emerge from eggs in early spring when they begin feeding on a large variety of trees. Eggs are laid in mid-summer and overwinter. Buff color egg masses contain 75-700 eggs & can be found on tree trunks.  Outbreaks are cyclical.  In 2021, our region had a significant outbreak with major tree damage. Most healthy trees can withstand a year of leaf loss dependent on how much defoliation took place. But defoliation reduces the resistance of trees making them more susceptible to pests and diseases and reach destructive levels.



Emerald Ash Borer

A small beetle that attacks only ash species. Signs of infestation include dieback, thinning, usually starting at canopy top, epicormic shoots from the tree base, woodpecker activity and bark splitting. On the trunk and branches, look for small (1/8 in. diameter) D-shaped holes that are left by emerging beetles.  When the bark splits or falls off, S-shaped larval galleries may be visible. Ash seeds are a food source for bird & mammals. The tree is used for flooring, furniture, lumber and pallet manufacture. Heavily infested trees die within 2-3 years of when symptoms are observed.


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Hemlock Woolly Adelgid (HWA)

Tiny insect from Asia that attacks Eastern Hemlock Trees. Appears as white wooly masses clumped on the base of the needles under the outermost branches. Hemlocks are well suited for growing on steep slopes, stabilizing shallow soils and providing erosion control. If HWA is not controlled, vulnerable animal populations are expected to diminish and most of the region’s hemlocks will be killed within the next decade. If you see something suspicious, note the location, take pictures and report it right away by calling the DEC forest pest hotline at 866-640-0642.



Japanese Knotweed

Introduced into the US from Asia as an ornamental and is now one of the most common invasive plants in the Adirondacks, spreading rapidly along stream banks, rivers, roadsides and woodlands while crowding out and altering the landscape. Its shallow, but extensive root system is ineffective at preventing streambank erosion or stabilizing soils.  Stands are very easy to identify. Stalks are persistent through winter. Heart-shaped or broadly ovate leaves grow in an alternating pattern on the stem and average 6’ in length and 3 – 4’ in width. Colonies are dense and thrive in shade and sun.  Clusters of small greenish white flowers arranged in spikes near the end of the stem bloom in Aug. to Sept. turning to buckwheat-like seeds by early October. It can damage homes and properties with its ability to grown through hard and dense materials (e.g.; cracks in foundations).


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Purple Loostrife

An erect, hardy invasive herbaceous biennial averaging 3-7 feet, preferring open sun and moist soil conditions.  Grows along roadside ditches, marshes, river banks, edges of ponds.  It has five or six petaled magenta flowers arranged close to the stem emerging in July and remaining thru Sept.  Leaves are lance-shaped, typically opposite or whorled with smooth edge.  Stems are square / four sided and rigid.  Spreads quickly by seeds and crowds out native wetland vegetations such as cattails, grasses, sedges and rushes. Impact on native wetland has been disastrous with PL virtually eliminating all other plants and affecting the entire ecosystem.


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Wild Parsnip

An herbaceous biennial/perennial plant from Europe & Asia that thrives in full sun along roadsides & fields, growing 2-5 ft tall with celery-like leaves. It looks similar to Queens Ann Lace, but has yellow flowers. Blooms June thru August with small, five petaled yellow flowers arranged in a flat topped, 2 – 6” broad umbrella. Taproot is long cone-shaped and thick.  DO NOT TOUCH THIS PLANT! Its sap causes a painful and blistering rash that persists for up to 6 months and may require medical attention. The sap contains chemicals which can make skin vulnerable to sunlight / UV radiation.


If you see something you suspect may be an invasive, note the location, take pictures and report it to

Thanks for your help!

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