Leadplant is a semi-erect native perennial forb growing 1 to 3 feet high, on branching stems which become woody with age. New stems are green and finely hairy.
The leaves are compound, pinnately divided into 13 to 25 pairs of leaflets plus a terminal leaflet. Leaflets are ovate, about 1/2 inch long and half as wide. The leaf undersides and stems are covered with small whitish hairs, which as the leaf ages, give the plant a grayish hue, hence the common name referring to 'lead'. The prominent central leaflet vein extends beyond the rounded tip of the leaflet, forming a sharp point.
The inflorescence consists of spike-like clusters (5 to 20) of small flowers at the ends of the stems. The weight of the spikes tends to cause the plant to tilt over, making it 'semi-erect'.
The flowers are 5-parted with a 5-toothed purplish hairy calyx and a corolla which has a single petal that forms first a tube and then opens horizontally - looks like a small mouth; initially shielded beneath it are the 8 stamens, pistil and style. This petal is the typical banner petal of a pea family flower. The laterals and keel petals are missing. The corolla varies in color from blue to purple. The protruding bright stamens are quite noticeable with reddish filaments and yellow-orange anthers.
Seed: Fertile flowers produce an oblong, curved hard seedpod containing 1, or sometimes 2, seeds. Seeds require a short period of cold stratification for germination.
Habitat: Leadplant is a shrub of the uplands and prairies. It is highly drought tolerant due to a deep tap root, which also makes transplanting a poor idea. Full sun is needed for sturdy flowering plants but a variety of soils are tolerated in mesic to dry moisture conditions. The lower stems are woody and on the prairie, periodic burns rejuvenate the plant; in the home garden it will be necessary to periodically prune out old wood. It is a common native prairie inhabitant.
Names: The genus Amorpha, comes from the Greek amorphos, meaning 'shapeless or deformed' and refers to the single petal flower. The species canescens is from the Latin and refers to the whitish or hoary color tinge from the fine leaf and stem hair and from which comes the common name of 'lead' plant. The alternate name 'Devil's Shoestrings' comes from the deep roots which farmers were never able to plough out. The author name for the plant classification - ‘Pursh’ is for Frederick Traugott Pursh (1774-1820) German-American botanist who wrote A Systematic Arrangement and Description of the Plants of North America, and was the botanist who catalogued and described the plants brought back by the exploring expedition of Lewis and Clark.
Comparisons: Leadplant is one of three Amorphas found in Minnesota. The other two are A. fruticosa, Desert False Indigo, which is a much taller plant, growing to 12 feet, leaves 4 to 8 inches long, and generally found in the moist soils of river banks; second is A. nana, Fragrant False Indigo, which is a shorter plant with pinkish flowers, no hair on the calyx and much less hair on the leaves.
Above: The Leadplant flower spikes are frequently found leaning over into the under story-plants. These photos of blooming plants are from first week of July.
Below: 1st photo - The single bluish petal wraps around the reproductive parts. Stamens and style are exserted when the flower is mature.
Below: 1st photo - The flower has a single petal, hardly visible in this photo, the hairy calyx dominates. Stamens have yellow anthers and reddish filaments, the style is also reddish. 2nd photo - The seed pods of October.
Below: 1st photo - The large taproot of a young plant. 2nd photo - The underside of leaves and the stems are covered with small whitish hairs, which as the leaf ages, give the plant a lead-color hue. 3rd photo - A dense cluster of flower buds forming. Clusters can have up to 20 spikes.
Below: Leaves have 13 to 25 pairs of 1/2 inch long leaflets plus the terminal leaflet.
Notes: Leadplant is not indigenous to the Garden. Eloise Butler first recorded planting this species on Sept. 10, 1910 with plants obtained in Lake City, MN; additional plantings in 1915, '22, '25, and '27. Martha Crone planted 3 in 1945, more in 1946 and '47 and sowed seeds in 1953. Leadplant is found throughout most of Minnesota except the NE quarter, and is generally found in most of the Central United States Plains areas south to Texas. In Canada it is known in Manitoba and Ontario.
John C. Fremont wrote on June 17, 1842 in his journal of The Exploring Expedition to the Rocky Mountains: ". . . and many beautiful plants in flower, among which the Amorpha canescens was a characteristic, enlivened the green of the prairie. Along our route the Amorpha has been in very abundant but variable bloom - in some places, bending beneath the weight of purple clusters; in others, without a flower. It seems to love best the sunny slopes, with a dark soil and southern exposure. It rivals the grass in quantity." On that day the exploring party was at 96º 32’ 35” L. 39º 45’ 08” lat. on the Kansas and Lower Platte Rivers in present day Kansas.
Eloise Butler wrote on the Amorphas: The amorphas - camp followers of their military cousins, the petalostemums - have pale, hoary, pinnate leaves and narrow flower spikes. The typical flower of their tribe - the pea - is butterfly shaped, with five petals: The broad standard, or banner, two slender side petals, the wings, and two partially united petals, the keel, arched over the stamens and pistil.
The amorphas have but one of these petals, the standard, the purple color of which contrasts pleasingly with the yellow stamens. Amorpha leaves are used in hard times as a substitute for tea. Farmers call the smaller species of the genus “shoestrings” because the roots thickly interlace the soil and make plowing more laborious. [Published July 23, 1911.]
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"