Emersed Weeds

Alligatorweed is an emersed plant. It can grow in a variety of habitats, including dry land, but is usually found in water. It may form sprawling mats over the water or along shorelines. Alligatorweed stems are long branched, and hollow. Leaves are simple, elliptic, and have smooth margins. The leaves are the opposite. The whitish papery flowers grow on stalks. Alligatorweed flowers during the warm summer months.

Also known as: Green lead plan; pigweed

Floating leaves are circular, and are attached to stems that are anchored in the soil. The leaves create a bowl-like appearance and do not lay flat on the water surface. Yellow flowers emerge from the plant.

American Water-willow is found in places with an abundant water and sunlight supply and is seen as both a shrub and a large tree. It often has multiple trunks, each with many branches coming from each. American Water-willow leaves are long and thin. The leaves are shiny green on top, and pale green on the underside and are three to five inches long and may have very fine teeth. The tree bark is dark brown or black with ridges.

Arrowhead is a shallow aquatic weed with leaves that are shaped like an arrow. (They also resemble a wishbone.) Leaves are above the water most of the time, but can sometimes be submersed or floating. Arrowhead has distinct veins that can be seen on leaves that arise from a common point. The flowers and fruit are produced on leafless stems. These may reach 1.5-3 feet tall. Flowers have three sepals and three white petals. The petals are 8-14 mm long. The root system resembles a bulb.

Bulrushes grow in shallow water and moist soils, so shorelines of ponds provide a great habitat for these plants. Some may reach 8 - 10 feet in height. Some bulrush species have three sided stems like sedge. Leaves grow on the lower stems and irregular seed clusters are densely packed located near stem tips.

Cattails have dense, "sausage-like," spikey flowers, called the catkins that appear on top of the long, slender stems in late summer to early fall. Cattails can be partially submerged or in boggy areas with no permanently standing water and can grow to 5 or 10 feet in height. They provide a wildlife habitat and refuge. Overgrowth can choke off open water, driving away birds.

Creeping water primrose is a perennial plant that stands erect along the shoreline but also forms long runners (up to 16 feet) that creep across wet soil or float out across the water surface. The leaves vary from green to red tinged. The plants flower yellow in all seasons except winter. The yellow flower is very distinctive of creeping water primrose. Flowers vary in size from 1 inch to 2 inches in diameter.

Dollarweed is also referred to as pennywort. The leaves are round in shape and approximately one inch in diameter. The leaves are dark green and glossy with scalloped edges. The petiole of pennywort is attached to the center of the leaf. The flower is small with five white petals and forms in clusters on the end of long stems. Dollarweed spreads by seed and rhizomes.

Maidencane is part of a family of perennial grasses that are common but somewhat hard to tell apart. Maidencane can grow up to 8 feet tall and often forms dense colonies. It has long, narrowly tapered leaves (up to 12 inches long and 1 inch wide) with rough upper surfaces and margins. Flowers are on a long narrow spike (up to 12 inches long). Maidencane forms extensive rhizomes by which it spreads rapidly.

Phragmites is a large grass native to wetland sites throughout temperate and tropical regions of the world. The erect stems can grow to 3 - 18 feet tall, with taller plants growing in areas with hot summers and fertile growing conditions. The leaves are broad for a grass. Seed pods emerge at the top of the plants.

The native pickerelweed is a very common emersed plant. It is a prolific grower and can cover large areas. Pickerelweed typically grows to about 2 to 3 feet tall. Its leaves are large, up to five inches wide, and are usually twice as long. Leaf shapes are variable, but are usually lance-shaped. The easiest way to recognize pickerelweed is by its spike of violet-blue flowers. Each flower lasts only one day.

“Leaves of three, leave it be.” Poison ivy can appear as a ground cover, a shrub, or as a vine growing up a tree. It likes to grow in places where it is moist. Older vines are covered in fibrous roots resembling hair that grow into the supporting tree. It has dull or glossy compound leaves on a long stem that are divided into 3 leaflets.

The name Poison Oak is often applied to the shrub-like forms of Poison Ivy. Poison Oak of the southeastern United States has its leaves divided into three leaflets; the leaflets are densely haired and generally have three to seven distinct lobes. The white, berry-like fruits are also somewhat hairy. Poison oak contains poisonous substances that are believed to be identical or closely related to that found in Poison Ivy.

Purple Loosestrife is a herbaceous perennial plant that grows 3 - 6 feet or more in width with numerous erect stems growing from a single woody root mass. The stems are reddish-purple and square in cross-section. Purple Loosestrife has reddish-purple flowers with six petals. Once this plant begins growing, it spreads rapidly. Purple Loosestrife enjoys growing in areas where it is moist.

Sedges thrive in wet places and have triangular (3-sided) stems. There are about 2000 species of grass-like perennial herbs in the sedge grass family. They are found worldwide, but they are most common in temperate and cold regions. Sedges can be distinguished from grasses by their solid, 3-angled flower stems (grasses have round, hollow flower stems). Most species of sedges form a dense, compact clump.

Smartweed is a perennial plant that forms dense colonies in shallow water or moist soils and can grow to 3 feet tall. Smartweed leaves are oblong, and stems are jointed. Leaves are arranged alternately upon the stem. Flowers are white or pink and are small. Smartweed may be emersed or submersed with only the flowers being displayed.

Spike rushes are small plants that look similar to grasses and sedges. Spike rush can grow completely underwater and appear as a submerged plant. Stems are unbranched with sheaths around the base but can be round, square, or flattened depending on the species. All spike rushes have small fruiting spikes at the tips of the stem.

Torpedograss is a non-native grass. The rhizomes are extensive and stems are rigid. Leaf blades are narrow, up to 10 inches long and approximately 1/4 inch wide. The plant is grayish-green with thin hairs on the upper surface. Torpedograss produces spikelets that are stalked with white and yellow flowers.

Water chestnut is an annual, rooted aquatic plant with a leafy rosette that floats on the surface. Stems can reach up to 16 feet, supporting two types of leaves. Submersed leaves are feathery, whorled along the stem and up to 6 inches long. Leaves are triangular, 1 to 2 inches long, waxy and have toothed edges. Leaf stems have a bladder-like swelling that provides buoyancy. Flowers are small, white, have 4 petals and bloom from mid-July to fall frost. The fruit is a one-inch wide woody nut armed with 4 stout barbs. The sharp barbs are a painful hazard to swimmers and bare feet.

Water shield is a rooted plant with floating oval or round shaped leaves that are a vibrant green on top with purple to red undersides. Small purple or pink flowers extend on a long stalk above the water. Water shield is also commonly called “snot grass,” due to the unusual and distinctive gelatinous or slimy covering on its roots and stems.

The white water lily is a perennial plant that often forms dense colonies. Water lily is one of the most recognizable floating aquatic plants. Sold as decorative plants for ponds and water gardens, this species can spread rapidly if left unmanaged. It is a rooted, emersed plant with large, notched, plate-like leaves with flowers that are white. The flowers may float or stick above the water and each opens in the morning and closes in the afternoon. The flowers are very fragrant.

Wild rice grows in shallow water, generally less than 3 feet. It looks like grass growing in the water. Late summer is when the seeds mature and look like oats or wheat. When the plants mature, they stand several feet above the surface of the water. During the growing season, wild rice is green, but when it is mature, the seeds are brown.

Yellow water lilies are perennial plants that arise on flexible stalks from rhizomes and large fleshy roots that can resemble bananas. Leaves are oval heart-shape, 3 to 6 inches in diameter, shiny dark green on top and reddish-purple underneath. Leaves float on the surface and are seldom emergent. Flowers are large (2 1/2 to 4 inches) bright yellow and usually stand above the water on separate stalks.