Monkshood

Aconitum

A genus of perennials that are closely related to the Delphiniums.
All parts of the plant are very toxic and must not be eaten by humans or pets. It is also best not to get the poisonous juices in open wounds.
Monkshood prefers full sun to partial shade on moist, fertile, humus-rich, well drained soil. They prefer cool summers and especially hate hot summer nights. Plants installed during autumn should be mulched with straw during the first winter to prevent frost heaving. The crowns should be just below the soils surface. Mulching during spring to keep the roots cool is recommended, non-invasive groundcover will also help keep the roots cool. Prune off faded foliage during summer to encourage new growth during cooler weather as autumn approaches. Insect and disease problems may occur, these including aphids, rust, mildew, stem rot and wilt. Rabbit and deer avoid them. They do not like root disturbance however division can be done during late autumn or early spring while dormant then replanted at the same depth. They will rot if planted too deep.

Aconitum baicalense ( Baikal Monkshood )
A perennial, reaching up to 5 feet in height, that is native to eastern Siberia, south into Mongolia.
The palmate leaves are up to 4 x 6 inches in size.
The blue or purplish-blue flowers, up to 1.3 inches across, are borne over a period lasting up to 4 weeks during early to mid-summer.
Hardy zones 3 to 7 in partial shade on moist, well drained soil.

Aconitum carmichaelii ( Autumn Monkshood )
Also called A. fischeri. An upright perennial, reaching a maximum size of 7 x 4 feet, that is native from Yunnan Province to Manchuria in China; south to Vietnam. It is found on grassy slopes, mountain meadows and woodland edge in the wild.
The leathery, toothed, 3 to 5 lobed leaves are up to 4.5 x 6 inches in size. The foliage is glossy deep green above, pale beneath.
The attractive foliage generally reaches no higher than 2 feet on the stem.
The blue, purplish-pink or white flowers are borne on short, dense spikes, up to 10 ( rarely over 5 ) inches long, during early autumn.
Hardy zones 2 to 7 in full sun to partial shade. Staking may be required for taller varieties on windy sites.

* photos taken on Oct 22 2013 in Towson, MD

* photos taken on July 17 2018 @ Leacock Museum in Orillia, ON

'Arendsii'
Reaches a maximum size of 6 x 4.3 ( rarely over 4 x 3 ) feet, with attractive lobed foliage that is glossy green and remains attractive all season long.
The showy, deep blue, hooded flowers are borne on sturdy spikes during early to mid autumn, often persisting until autumn frosts.
The flowers attract hummingbirds and butterflies.
Hardy zones 3 to 8 in full sun to partial shade on cool, moist, fertile, well drained soil.

* photo taken on May 6 2018 in Columbia, MD

* photo taken on June 15 2018 in Columbia, MD

* photos taken on July 5 2018 in Columbia, MD

* photos taken on Apr 18 2019 in Columbia, MD

* photos taken on Oct 8 2019 in Columbia, MD

* photos taken on Oct 21 2019 in Columbia, MD

* photos taken on Mar 21 2020 in Columbia, MD

* photo taken on June 8 2020 in Columbia, MD

* photo taken on May 19 2021 in Columbia, MD

* photos taken on June 8 2021 in Columbia, MD

* photos taken on Oct 21 2021 in Columbia, MD

* photos taken on Oct 15 2022 in Columbia, MD

* photos taken on Oct 24 2023 in Columbia, MD

* photos taken on Oct 9 2024 in Columbia, MD

'Barkers Variety'
Reaching a maximum size of 7 ( often only 3 ) x 4 feet with intense violet-blue flowers borne late summer into early autumn. It often breeds true from seed.

'Blue Bishop'
Reaches up to 6 feet with violet-blue flowers.

'Cloudy'
Reaches a maximum size of 6 x 4.3 ( rarely over 4 x 3 ) feet, with attractive lobed foliage that is glossy green and remains attractive all season long.
The showy, lavender-violet and white bicolored, hooded flowers are borne on sturdy spikes during early to mid autumn, often persisting until autumn frosts.
The flowers attract hummingbirds and butterflies.
Hardy zones 3 to 8 in full sun to partial shade on cool, moist, fertile, well drained soil.

var. 'wilsonii'
Vigorous and taller, reaching up to 8 feet, with purplish-blue flowers borne mid-summer into early autumn.

* historical archive photo

Aconitum columbianum ( Columbian Monkshood )
Similar in appearance to A. carmichaelii, it reaches up to 3 feet. It is native to western North America ( from Bear Lake in central British Columbia to far southwest Alberta to central Montana to the Black Hills of western South Dakota; south to central California to southeast Arizona to southwest New Mexico. It is found in coniferous forest, meadows and bottomlands in the wild.
The 3 to 7 ( usually 5 ) leaves are up to 6 inches wide. The foliage is glossy mid-green. The flowers are intense mid-blue ( rarely white ).
Hardy zones 4 to 5 ( possibly 3 for central Montana seed source ).

* USDA-NRCS PLANTS Database

* photo taken by Sheri Hagwood @ USDA-NRCS PLANTS Database

* photo taken by Jean Pawek @ CalPhotos

Aconitum episcopale ( Climbing Monkshood )
A twining, herbaceous perennial vine, reaching up to 20 feet each season. It is native to mountain woods in Sichuan Province in China.
The deeply-lobed leaves, up to 3.5 x 4 inches in size, are glossy mid-green.
The hooded, violet-blue flowers are borne 4 to 8 in inflorescences during late summer into early autumn.
Hardy zones 4 to 9 in full sun to partial shade on just about any well drained soil. It prefers moist soil but will tolerate drought once established.

Aconitum fischeri ( Azure Monkshood )
A moderate growing perennial, reaching up to 6 x 3 ( rarely over 3 ) feet, that is native to grasslands and open woods in eastern Siberia, Manchuria and Korea.
The glossy leaves, up to 5 x 6 inches in size, resemble that of the Silver Maple in shape.
The showy, blue flowers are borne 4 to 6 on inflorescences all summer long.
Hardy zones 3 to 6 in partial shade.

Aconitum henryi 'Spark's Variety'
A tuberous rooted, upright perennial, reaching up to 6 x 3.3 feet, the parent species is native to Sichuan & Hubei Provinces in China.
The 7-lobed leaves are glossy deep green.
The large, vivid deep violet-blue flowers are borne during mid to late summer.
Hardy zones 2 to 6 in partial shade.

Aconitum x hybrida ( Hybrid Monkshoods )
Also called Aconitum x cammarum. These Monkshoods mostly bloom on sturdy, upright spikes during summer.
Hardy zones 3 to 6 in partial shade.

'Bi-color'
Reaches up to 5 feet in height, with showy blue and white flowers borne during summer.

'Bressingham Spire'
Compact and very upright in habit, reaching up to 3.3 x 3 feet, with deep purplish-blue flowers borne on long sturdy spikes during mid to late summer, often persisting into autumn. It does not need staking.

'Eleanor'
Compact in habit, reaching up to 4 x 3 feet, with white ( variegated with narrow blue edge ) flowers, borne all summer long.

'Ivorine'
Creamy-white flowers.

'Newry Blue'
Reaches up to 5 feet in height, with bright violet-blue flowers borne during early summer.

'Spark's Variety'
Reaches up to 6 feet with purplish-blue flowers borne on branching stems during mid to late summer.

'Stainless Steel'
Reaches a maximum size of 3.5 x 2 feet, with gray-green foliage and intense blue ( with white center ) flowers borne all summer long.

Aconitum napellus ( Common Blue Monkshood )
A vigorous, long-lived, upright perennial, reaching a maximum size of 6 x 3 ( rarely over 4.5 ) feet, that is native to Europe and western Asia.
The toothed, 5 or 7 lobed leaves, up to 6 inches across, are lightly hairy and glossy deep green.
The bright purplish-blue flowers are borne in dense racemes during early to mid summer.
Hardy zones 2 to 6 in partial shade.

* photo taken by Milan Havlis, owner of central Europe's premier plant nursery

'Album'
Pure white flowers, otherwise identical.

'Rubellum'
Reaches up to 3.5 feet in height, with pale pink flowers borne early to mid summer.
It is sometimes mixed in plantings with the regular blue flowering species.

Aconitum pyrenaicum ( Yellow Monkshood )
Also called Aconitum lamarckii.
A perennial, reaching a maximum height of 5 feet, that is native to Europe.
The pale-yellow flowers are borne all summer long.
Hardy zones 2 to 6 in partial shade. It is very easy to grow.

Aconitum raddeanum
A perennial, reaching up to 4.5 feet in height, that is native to far eastern Russia as well as the far northern China.
The deeply-lobed palmate leaves shaped like that of the Silver Maple are up to 3.5 x 4 inches in size.
The purplish-blue flowers are borne on upright spikes during mid-summer.
Hardy zones 3 to 6 ( est ) in partial shade on well drained soil.

Aconitum septentrionale 'Ivorine'
Also called Aconitum vulparia 'Ivorine'. A compact perennial, reaching a maximum size of 7 x 3.3 feet, with creamy-white, hooded flowers borne on short spikes during late summer into early autumn. The parent species is native from Europe through Siberia, Mongolia and Manchuria. It is usually found in birch forests in the wild.
The leaves are up to 9 inches across.
Hardy zones 2 to 6 in partial shade.

Aconitum tauricum ( Taurus Monkshood )
A perennial, that is native to mountains in Italy.
The attractive foliage is finely dissected.
The purple flowers are borne on dense clusters.