Algae & Plant ID
Algae
Filamentous
Also known as “pond scum” or “scum,” this type of algae can form dense, hair-like mats on the water’s surface. If left untreated, the mats can cover the entire surface of the pond. There are many species of filamentous algae and often more than one species will be present at the same time in the pond.
Water Net
Hydrodictyon is a type of filamentous algae characterized by a hollow, tube-like structure. Upon closer examination, these tubes appear to be comprised of a hexagonal netting. Fragmentation and rapid growth in nutrient-rich water allow this algae to quickly overtake a pond.
Chara
Chara /Muskgrass is often mistaken for a vascular plant, but is actually a form of algae. It grows most commonly in shallow water where the nutrient levels are high. Its rough texture and strong, musty odor, almost garlic-like, easily distinguishes it when pulled from the water.
Planktonic
Also known as “blue-green” algae, this type of algae is actually millions of microscopic plants that give the pond a “pea-soup” appearance. If left untreated, natural die-off in the fall may cause a fish kill.
Harmful Algal Blooms
Microcystis
Thick colonies throughout water or as surface scum, grey green to blue-green color, can form pea soup looking surface scums, toxin and taste/odor producer.
Oscillatoria
This troublesome variety of cyanobacteria forms small spongy masses that grow on the bottom and eventually float to the surface. It often has a dull gray color and is difficult to control.
Anabaena
Often observed as blue or green in color, this cyanobacteria has been linked to human and animal illnesses, often resulting in vomiting, diarrhea and abdominal pain.
Euglena
Euglena are unicellular organisms that inhabit nutrient-rich ponds and lakes, often turning the water a reddish-brown color. The severity and occurrence of red cyanobacterial blooms are limited by phosphorus availability in the water column.
AQUATIC PLANTS
(Shoreline / Emergent)
Cattails
Cattails inhabit wet lowland areas and pond perimeters with the ability to grow in as much as 4 feet of water. The long, slender, grass-like stalks can reach 10 feet in height with mature plants producing a catkin in mid-summer.
Common Reed
Common Reed is a large, invasive perennial grass found in wetlands throughout most of North America. It can reach 15 feet in height and forms dense stands capable of outcompeting native plants due to its invasive nature.
Scoring Rush
Scouring Rush is an ancient horsetail variety that gets its name from the silica in its cells. The silica, which gives the plant a rough texture, has been used to scrub cooking pots and polish metal. The silica reduces herbicide penetration and makes the scouring rush difficult to control.
Purple Loosestrife
Bright purple-hued flowers are terminally located on a 4-sided stem. Leaves are usually found in pairs and arranged oppositely on the stem. It is best to control this invasive species before it sets seed. Plants may reach 6-7 feet in height.
Bulrush
Bulrush is a native, wetland sedge that grows 2-4 feet high. With the potential to form dense stands, bulrush can be used to control shoreline erosion and create aquatic habitat. The unbranched stem often terminates into tight clusters of flowers and seeds.
Arrowhead
Arrowhead is a perennial plant that is often found around the edges of a pond in dense stands. Arrow-shaped leaves stand 2-3 feet tall. White blooms will often be observed in late summer. Strong roots allow this plant to survive fluctuating water levels and weather conditions.
Spike Rush
Spike Rush is comprised of green, leafless stems which vary in length from 5 inches to 4 feet. Plants grow in clumps and are tipped with brown spikelets. The are normally found along the shoreline or in shallow water.
Eelgrass
Eelgrass has ribbon-like, flaccid leaves. Each plant has a horizontal stem system connecting tufts of leaves and blooms in late summer. Eelgrass often grows to the surface where it impedes recreational activities, such as boating and swimming.
Free-Floating
Duck Weed
This small floating green plant has a 1-2 inch thread-like root and is often mistaken for algae. It is most commonly seen in older, nutrient-rich ponds. Duckweed is notorious for covering the entire pond surface and may induce a fish kill by not allowing sunlight to penetrate the water.
Watermeal
Watermeal is a small granular plant that lacks roots. It thrives in still, nutrient-rich conditions and may be seen alone or growing with duckweed. Watermeal is difficult to control and may require several herbicide applications.
Azolla Fern
Azolla fern forms a dense mat on the water surface. Each plant dangles thread-like roots into the water. Under certain conditions, azolla fern turns a reddish-brown color. With the ability to double its concentration in 7 days, this plant is extremely invasive.
Submerged
American Pondweed
American pondweed has floating, sword shaped leaves. This plant can be easily identified in ponds where its floating leaves form a mat on the surface. It is best controlled in the early stage of development before the formation of a nutlet and subsequent seed dispersal.
Variable Leaf Pondweed
Variable-leaf pondweed is a perennial plant comprised of two kinds of leaves. The floating leaves are “”leathery”” and oval in shape, while the submerged leaves are thin and longer than the floating leaves.
Floating Heart
Floating heart produces yellow flowers that stand 1-3 inches above the surface of the pond. The foliage is slightly variegated resembling a typical, but small, water lily leaf. It has the ability to spread throughout the pond via its extensive root system.
Water Shield
Water shield has floating, oval leaves that resemble small water lilies. These leaves rarely exceed 4.5 inches and exhibit no slit. Water shield has a very distinctive mucus-like, or gelatinous, coating on stems and new growth tips. Often found in acidic waters, water shield provides excellent habitat for fish and waterfowl.
Spatterdock
Spatterdock is a large, water lily-like plant with floating and immersed, heart-shaped leaves. The round, yellow flowers are smaller than golf balls. Spatterdock can spread by both seeds and its large spongy rhizomes. Control often requires multiple herbicide treatments.
Water Lily
Water lilies are often intentionally planted for fish habitat or aesthetics. Water lilies spread very quickly due to their elaborate root system. Each stem produces a round leaf 6-12 inches in diameter. Leaves are usually green with reddish-purple undersides.
Eruasian Watermilfoil
Eurasian watermilfoil is one of the most aggressive and problematic aquatic weeds to infest ponds and lakes. Stems are reddish in color with fan shaped leaves. This plant spreads easily through fragmentation.
Hydrilla
Hydrilla has leaves with toothed margins and a toothed mid-rib. The leaves are arranged in whorls of 4-8. Hydrilla is a major problem throughout much of the United States, because it is difficult to control and its tubers are winter hardy.
Coontail
Usually found in hard water, coontail is found completely submerged but lacks roots. The dark green forking leaves are arranged in whorls on the stem. Coontail can be found throughout the continental United States. It is difficult to control and may require several herbicide applications.
Parrotfeather
Parrotfeather is an immersed plant often seen trailing along the pond edge. The leaves are deeply cut and feathery-looking, bright blue-green in color and arranged in whorls of 4-6 around the stem.
Brittle Naiad
Brittle naiad is often found growing in clumps and can be identified by its bushy appearance under water. The long, pointed leaves have distinct spines and are oppositely arranged on the stem. The entire plant is brittle and breaks easily
Southern Naiad
Southern naiad is a leafy plant with wider leaves at the base. The leaves are arranged oppositely or in whorls of three around the plant stem. The leaf margins contain visible spines, while the leaf axis often conceals a tiny seed. This plant frequently grows in thick beds that make control difficult.
Small Pondweed
Small Pondweed is a perennial, submersed aquatic weed. Slender, ribbon-like leaves alternate on the thin stems. Common along shorelines in depths up to 8 feet, small pondweed forms dense clumps that may impede fishing and other recreational activities.
Curlyleaf Pondweed
Curly-leaf pondweed leaves are green with a reddish hue. The wavy margins on the sides of its leaves make this plant easy to identify. Curly-leaf pondweed thrives in the early spring before most pond weeds are prevalent.
Brazilian Elodea
Often referred to as anacharis, Brazilian elodea has leaves arranged in whorls of 4-6. It is bright green in color with a relatively smooth leaf edge and produces a small, white flower.
Clasping-Leaf Pondweed
Clasping-leaf pondweed has a wide, wavy leaf with a broad base that extends three-quarters of the way around the stem of the plant. The leaves are alternatively arranged on the stem, with the upper stem appearing branched and leafy.