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Ornamental Plants for Minnesota Gardens

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Common Name
Garden Monkshood (Garden Aconite, Venus-chariot, Helmet Flower, Wolf's Bane)

 

Scientific Name
Aconitum napellus L.

 

Plant Family
Buttercup (Ranunculaceae)

Garden Location
No longer extant in the Garden

 

Prime Season
Late Summer to Autumn

 

 

The Monkshoods are so named from the flowers that resemble the cowls of monk's habits of the old days. Garden Monkshood is an erect perennial herb, growing 1 to 4 feet high on stiff leafy stems. The stem is green with some reddish overtones and with fine short hair.

The leaves are both basal and stem. The basal leaves are stalked, palmately divided into 3 to 7 segments with leaf margins deeply incised and with a few large teeth. The stem leaves are alternate and similar in shape with size and number of lobes decreasing toward the top of the stem. Upper most leaves are almost stalkless.

The inflorescence is a terminal raceme, up to 8 inches high, with axillary racemes from the upper leaf axils. Each flower on a long stalk with fine hair.

The flowers are bisexual and bilaterally symmetric. The parts you see forming the Monk's hood are the five large sepals that are purplish to dark blue in color, shading into lighter shades on some plants such as violet or whitish-violet. Two sepals jut forward at the base of the flower, 2 lateral are roundish in shape and also grow forward while the fifth largest sepal is above forming the hood. It is usually crescent shaped, arched with a small beak on the front. The outer surface of the sepals is finely hairy. There are 2 small long-clawed petals enclosed in the hood. These have a hammer shape with a spur with nectaries on the spur. There are from 25 to 50 stamens, no staminodes, and 3 (sometimes 5) pistils, with styles. The stamens are depressed in the throat at first, but when the pollen is ripe they extend, several at a time so as to dust the bees which must get into the flower to reach the nectaries. Beneath each flower is a green leafy bract.

Seed: Fertile flowers produce a follicle, oblong with a beak, somewhat looking like a pea pod, containing a number of small triangular shaped seeds. The follicles split open when mature to release the seeds.

Toxicity: Poisonous - see notes at bottom of page.

 

Habitat: Garden Monkshood has a tuberous root system with a crown. It grows best in moist rich soils in full sun to part shade, part shade preferred. Excess moisture will rot the crown and the plant does not tolerate dryness. Plants are slow to develop, especially if divided and transplanted. Roots are brittle. Once established, let them be. The plant is not aggressive and deer tend to avoid it.

Names: Stern (Ref. #37a) states that the genus Aconitum is derived from the Greek akoniton, their name for this group of poisonous plants. Some say the word means 'a dart' referring to the use of poison tipped darts and arrows used in ancient times. Theophrastus and Pliny believed it came from akonae, the supposed place of its origin (Ref #7). The species name, napellus, is from napus, meaning 'little turnip' and referring to the shape of the root tubers. The author name for the plant classification - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. As to some of the alternate common names, Wolf's bane comes from the use of the poisonous root to kill wolves. Helmet-flower was the name in Shakespeare's day.

Comparisons: There are around 100 species of Aconitum worldwide - most in Asia. There are cultivars available from the nursery trade with varying colors of the sepals. The flower shape, however, is distinctive.

See bottom of page for notes on the Garden's planting history, distribution in Minnesota and North America, lore and other references.

Flower raceme drawing

Above: The flower raceme of Monkshood showing several axillary branches. Drawing of Monkshood courtesy Kurt Stüber's Online Library.

Below: Five sepals form the flower, the upper sepal forming the hood contains two small petals with nectar spurs. Photo of dark purple flower stems ©Emmett J. Judziewicz, University of Wisconsin.

Monkshood FlowerFlower side view Purple flowers

Below: The palmate leaf structure.

leaves

Notes:

Notes: The Garden Monkshood is a native of Europe and used as an ornamental and medicinal plant for centuries. It was first introduced to The Garden in April 1946 and again in 1956, by Curator Martha Crone. She recommended the plant as one rabbits tend to avoid.

 

Toxicity and medicinal use: All species of Aconite contain the active poison Aconitine, a most deadly specific. All parts of the plant contain it but the root has the highest concentration. Of the various species of Aconite, A. napellus contains the most (or the best - depending on your view) of this alkaloid. For creating medicinal tinctures and liniments, the root (daughter roots) were collected in autumn before the bud for the next years stem developed. These were dried and powdered. When the drug was listed in the British Pharmacopoeia, specific instructions were given on harvest and preparation. As these alkaloids can enter the bloodstream from very small cuts, it is always recommended that plants be handled with gloves and avoid any skin contact. The drug was used as a diuretic and a diaphoretic. In proper quantities, relief from pain was obtained. The root was sometimes mistaken for Horse-radish by some diggers with sad results. In modern times use of Monkshood is much reduced.

Culpepper (Ref. #4b) reported that concoctions made from the Mulberry or from the Ground Pine were an antidote to the Aconite.

References and site links

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.

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