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Indianhemp (Apocynum cannabinum)
COMMON NAMES:
Indianhemp
common dogbane
dogbane
hemp dogbane
prairie dogbane
SCIENTIFIC SYNONYMS:
Apocynum hypericifolium Ait.
Apocynum pubescens Mitchell ex R. Br.
Apocynum sibiricum Jacq.
Apocynum suksdorfii Greene
TAXONOMY: The currently accepted scientific name of Indianhemp is Apocynum cannabinum L. Hybridization is a common occurrence in this genus. Apocynum × floribundum Greene is a hybrid of spreading dogbane (Apocynum androsaemifolium) and Indianhemp.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: Indianhemp is a native, perennial, broadleaf herb. In some cases, it is considered a weed. It has an erect to ascending growth habit and reaches heights of 2 to 6 feet (0.6-1.8 m) from a spreading root stalk Branching is opposite or sub-opposite. Indianhemp leaves, stems, and roots all contain milky juice.
Leaves: The leaves are opposite, ovate to lanceololate, entire, and glabrous to sparingly pubescent beneath.
Flowers: The inflorescence of Indianhemp is a trichasial cyme. The lateral cymes of the trichasium can continue growing vegetatively to form a complete stem with their own terminal trichasiums. The flowers consist of 5 petals occurring in terminal clusters from the leaf axils.
Fruit/Seed: The fruits are slender, pencil-like, hanging pods that are 4 to 8 inches (10-20 cm) long and occur in pairs. Seeds are flat, thin, and tufted with soft hairs.
Roots: Indianhemp has 2 underground organs: the 1st are thick, branched, horizontal rhizomes that produce new aerial shoots at variable depths. The 2nd are slender, well-branched, vertical, absorbing roots. These large roots/rhizome systems have been found as deep as 13 feet (4 m) below the soil surface and may extend up to 20 feet (6 m) in radial spread.
REGENERATION PROCESS: Indianhemp regenerates by seed and vegetative means. Regeneration is largely by vegetative means from rhizomes or from root crown buds located at the woody base of stems.
Apocynum species spread by cloning. Indianhemp reproduces by rhizomes or sprouting from the root crown. Aerial shoots arise from adventitious rhizome buds. Rhizomes spread extensively, forming new plants at "considerable" distances. Seedlings are capable of sprouting within 10 to 41 days of emergence.
HABITAT TYPES: Indianhemp prefers damp locations along streams and ditches and in marshes, though it can be found growing less abundantly in drier locations such as thickets, open woods, and open ground. It colonizes disturbed sites, abandoned agricultural fields, and prairie pot hole wetlands.
SITE CHARACTERISTICS: Indianhemp is seldom found on soils low in fertility. It grows best on fertile, medium- to heavy-textured soils.
SEASONAL DEVELOPMENT: Indianhemp blooms from spring until late in the autumn.
GENERAL DISTRIBUTION: Indianhemp is found throughout all of the United States and Canadian provinces (with the possible exceptions of Alaska and Yukon).
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Indianhemp is poisonous to all livestock, although domestic sheep are affected more than other animals. However, actual cases of livestock poisoning from Indianhemp are rare. Traces of Indianhemp were found in rumen samples of pronghorn and white-tailed deer in Montana, but no animals were observed eating it. Indianhemp is unpalatable at all seasons, even to livestock that are virtually starving. Animals usually avoid Indianhemp because of the bitter, sticky, milky-white juice; however, domestic sheep may eat large quantities if other forage is scarce.
Indianhemp is a primary host for 2 species of leaf beetle. It is also a host plant for Chrysochus auratus (a root beetle) in Iowa. Chrysochus auratus mating and ovipositing occur on Indianhemp throughout the summer. Once hatched, the larvae drop to the ground and tunnel to the roots of the host plants, where they feed and overwinter.
There is value in using Indianhemp for the rehabilitation of disturbed sites. It grows very well in disturbed areas. It is, for example, common on American badger-disturbed sites. It is also recognized as a worth-
while native landscaping plant because it spreads rapidly by vegetative means and can help suppress weeds.
Indianhemp is known for its importance to early Native Americans. The strong, fibrous root and stem fibers were used to make fish nets, rope, thread, baskets, cloth, and bags.
Indianhemp is known to have many medicinal purposes. The glycoside, cymarin, was used as a cardiac stimulant, a diuretic, a diaphoretic, a febrifuge, a rheumatism remedy, and a treatment for gall stones. The dried milky fluid in the stems can be used as a chewing gum substitute.
There may be potential for using Indianhemp as a hydrocarbon-producing crop as an energy alternative.
Indianhemp is considered a serious weed problem in agricultural fields in the Midwest and can cause decreases in yield. Infestations tend to occur in agricultural crops where no-tillage systems have been implemented, which allow for Indianhemp's rhizome and root system to become well established. Reductions in yield are reportedly due to allelopathic influences of Indianhemp. Indianhemp is also considered a weed species in nurseries, plantations where Christmas trees are grown, and in orchards.
