||Early Detection and Rapid Response
Wavyleaf basketgrass (Oplismenus hirtellus)
Wavyleaf basketgrass is a low-lying, trailing perennial grass that is less than one foot tall. Its flat leaf blades are about one-half to one inch wide and 1.5 to 4 inches long, have elongated pointed tips and are rippled. It is noticeably hairy where the leaf attaches to the stem, although the hairs are very short. Individual stems connect to each other underground. When the plant blooms, from mid-September through November, the grass sends up a spike that has seeds along it. Seeds are sticky and can stick to clothes, boots, etc.
Another invasive grass known to be in many Fairfax County parks looks similar to wavyleaf basketgrass but is taller, grows more upright and prefers full sun (wavyleaf basketgrass prefers shade). This invasive is small carpetgrass (Arthraxon hispidus).
Marsh dayflower/ Wart removing herb (Murdannia keisak)
Marsh dayflower (wartremoving herb) is an annual plant that invades wetlands in the southeastern and northwestern United States. Plant stems are not woody and appear fat because they retain water. They will have a "juicy" look to them like a green bean. The plant grows close to the ground. In August to November, small, pink, three-petaled flowers appear. They occur singly or in small clusters. The flowers are so small you may not notice them at first. Marsh dayflower invades water edges and marshes and can grow above or below water.
Linden viburnum (Viburnum dilatatum)
Leaves are opposite from each other, slightly toothed, dark green and often shiny. Leaf shape is highly variable from nearly round to long and narrow on the same plant. Leaves are two to five inches long and one to 2.5 inches wide. Leaves and young stems are usually covered in soft hairs. Leaves drop relatively late in the fall. Fruit turns bright red in September and October and will persist until December. Two circular, dark spots at the base of the stem usually can be seen on the underside of the leaf.
Yellow archangel (Lamiastrum galeobdolon)
Yellow archangel is a fast-growing, perennial ground cover that may be either like a vine along the forest floor or upright depending on conditions. Leaves are typically multi-colored with silvery-grey markings, oval-shaped, hairy and serrated like a knife. Stems are square, and leaves grow directly across from one another. Flowers are small, yellow and tubular. They grow in pairs of clusters close to stems and between leaves on flowering stems that are one to two feet tall. The plant has a distinctive, unpleasant odor.
Giant hogweed (Heracleum mantegazzianum)
THIS SPECIES IS TOXIC AND SHOULD NOT BE TOUCHED. IF SEEN, REPORT IMMEDIATELY!
Leaves are deeply indented, serrated and up to five feet across. There are numerous small white flowers in June or July clustered into a flat-topped flower stalk up to 2.5 feet wide. The stems are hollow, ridged, two to four inches in diameter and eight to 14-feet tall with purple blotches and coarse white hairs. The hairs are especially prominent at the point where the stem and the leaf stalks intercept. The stems will have purple markings on them.
Kudzu (Pueraria lobata)
Kudzu is a rapidly growing vine. The vines have a "woody" look to them and are covered in brown hairs. The large leaves are in three leaflets. Typically, the two outside leaves resemble mittens and the middle leaf has three lobes. However, the leaf shape is highly variable and all three can be simple ovals. The flowers grow individually and hang down from the stem. Flowers are about one-half inch long, purple or white, and sweet-smelling. Flowering occurs in late summer and is soon followed by production of brown, hairy, flattened, seed pods each of which contains three to 10 hard seeds.
Java Dropwart (Oenanthe javanica)
O. javanica is a popular vegetable eaten throughout its native range, which includes China , India , Indonesia , Japan and other East Asian countries. It's other common names include water dropwort, Chinese celery, and water celery. It invades the edges of water features and prefers wet soil. It can grow partially covered in water. The stems are cylindrical and upright or ascending from a creeping base. The leaves are arranged alternately along the stems and they are serrated, like a knife. Small white flowers are clustered together (like Queen Anne's Lace) and bloom in mid-summer.
Leatherleaf Mahonia (Mahonia Bealei)
Mahonia is an evergreen shrub that can grow up to 10 ft tall. Leaves are pinnately compound (like a fern) and up to 18 in long with 9-13 leaflets that resemble large holly leaves. Flowering occurs in late fall and early winter when fragrant, lemon-yellow flowers develop. Fruits appear in the spring in the form of green berries, about a half inch long, that turn bluish black with a grayish bloom. Fruits hang in grapelike clusters.