Aconite has long been a stalwart in our cottage gardens, presenting adorable flowers in early summer and fall depending on the species. We take a look at this poisonous beauty and give you some tips for planting and care.
Aconite (Aconitum) is part of the buttercup family (Ranunculaceae) and has long been a stalwart in our cottage gardens. In total, the genus contains around 300 species of which many come from Asia. Some are native to central Europe, mostly growing in nutrient-rich soils in shade, on moist meadows, at the edge of woodland and on mountain slopes. Both flowering in June, protected Aconitum napellus and Aconitum lycoctonum are both native to Europe.
All species have one thing in common: All parts of the aconite plant are toxic. Wolfsbane toxin (aconitine) used to be used to make poison arrow tips. Even intense skin contact with the plant’s sap can lead to symptoms of poisoning, such as temporary numbness and nausea. Although aconite is beautiful, it should therefore never be planted anywhere where children might come close to it. It’s also toxic to pets.
Appearance and Growth
Wolfsbane species include upright growers as well as ramblers. Depending on the species, they can grow to between 3.94 inches and 10 feet tall. Aconite leaves are dark green, more or less round and may feature deep serration in some species.
Some of the 300 aconite species bloom in early summer, such as Aconitum lamarckii and Aconitum napellus. Some bring color to summer beds and others, such as Chinese aconite (Aconitum carmichaelii “Arendsii”), wait until September and October to impress with their majestic flowers. Most wolfsbanes have striking blue panicles made up of lots of individual hood-shaped flowers. There are some wolfsbane species and garden varieties that have white, pink, delicate yellow or even red flowers, such as the white Aconitum napellus “Schneewittchen” or Aconitum hemsleyanum “Red Wine”. The latter boasts bold, dark burgundy flowers and can even climb, unlike other aconites.
Location and Soil
All aconite varieties have similar needs. They prefer nutrient-rich humus soil that is not too dry. A semi-shaded location under the leafy shade of trees and shrubs is ideal. If aconite is exposed to more sun, the soil must always be moist – groundcover ensures cool soil. If the soil is too warm and dry, this perennial is vulnerable to diseases such as mildew.
The best time to plant wolfsbane is in the spring. This way, the plant can successfully establish roots by winter. Wolfsbane can also be planted in summer and fall. As aconite prefers nutrient-rich soil, it will appreciate a little compost in the planting hole. Its love of nitrogen can be met with the addition of horn shavings into the planting hole. As wolfsbane plants vary greatly in height, the space required for each plant varies from species to species. You can generally find this information on the plant label. Monkshood is best suited to planting in beds or along the edge of woodland in sun to partial shade.
In the wild and in the garden, aconite is nutrient-hungry and enjoys regular fertilization with compost and horn shavings. Aconite seed heads should be removed immediately after flowering. The stalks should be removed as soon as the flowers have wilted completely.
After six to ten years in the same place, the plant should be divided in spring or fall - Chinese aconite (Aconitum carmichaelii “Arendsii”), however, should only ever be separated in spring. Some wolfsbane species (A. lycoctocum) have long lives so must only be separated in spring to propagate. To do so, dig up the turnip-like rootstock and separate the smaller roots from the main root. These root pieces can be simply planted with an inch or so of soil to cover. Put compost into the planting hole first - so this mysterious beauty can unfurl its full flower power in the following year. When dividing these particularly toxic roots, it’s best to wear gloves or wash your hands thoroughly after coming into contact with the plant.
Tall species and varieties of aconite in particular tend to fall over due to their long inflorescences. Metal obelisks or bamboo canes with ties provide the required stability.
As already mentioned, wolfsbane does best in sunny to partially shaded locations, so is great for combining with other perennials with the same needs. With its distinctive appearance and height, it’s especially suitable for growing alone and is often used as the main plant in a planting group. The mostly blue flowers form an attractive contrast to light-flowered shrubs. Popular partners in sunny beds include black cohosh (Cimicifuga), scarlet bee balm (scarlet monarda) or garden phlox (Phlox paniculata), while partial shade is ideal for white false goat’s beard (Astilbe) or light purple Japanese anemones (Anemone) as an excellent complement to the blue flowers. In cottage gardens, wolfsbane is often combined with foxgloves (Digitalis) or bellflowers (Campanula). White or light yellow aconite varieties, such as A. lycoctonum or A. lamarckii, look best in front of a dark background like a hedge. As the bottom leaves of an aconite plant often wilt during flowering, they should always be combined with companion plants that will cover up the base of the stem with thick foliage
Important species and varieties
4 foot tall Aconitum napellus and lesser-known Aconitum lycoctonum bloom as early as June. It has small, creamy yellow flowers and grows to just 31.5 inches tall. 4 foot tall Aconitum x cammarum follows in July with not just blue but also white-blue flowers. Sparks variety monkshood (Aconitum henryi) displays its deep purple flowers from July as well. This cherished summer flowerer can grow up to 5 feet tall and is well suited to semi-shaded locations. The dark blue-purple of its flowers gives Chinese aconite (Aconitum carmichaelii “Arendsii”) a touch of mystery. The best-known member of the aconite family grows to around 4.5 feet tall and brings up the rear with its late flowers in September/October.
The best way to propagate monkshood is by dividing its tuberous rootstock. All species, but not their varieties, can be grown from seed. You should be aware that aconite is a cold germinator, so needs low temperatures first to activate the seeds. The best time to sow is therefore between November and March.
Diseases and Pests
In some cases, bacterial leaf spot diseases, powdery mildew and, rarely, downy mildew may appear. If this perennial is planted in a location that is too wet, it may fall foul to verticillium wilt or sclerotinia sclerotiorum. The only option here is usually to remove the infected rootstock completely. In a very warm, sunny and dry location, black bean aphids can be a problem. Additional pests include leaf miners and cyclamen mites.