(Editor's Note: This article was originally published on December 27, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Leopard's-bane or Doronicum, are among some of the oldest cultivated ‘ornamental' flowers. Of the 35 species of Doronicum, surprisingly few are commonly cultivated; yet those that are cultivated have been grown for hundreds of years. The genus is native to Eurasia, growing from open woodlands, meadows to alpine regions. Depending on the species, their heights may vary from 20 cm to over 1 m. They are among the earliest-blooming ‘daisies' in our gardens, appreciated for their numerous yellow flowers which contrast and compliment the many spring bulbs that bloom concurrently with them. Leopard's-bane are also excellent cut-flowers. Please note that all are toxic.
Perhaps the most popular species is D. orientale, aka D. caucasicum or D. cordatum. This species is the most compact, hardiest (zone 4) and among the earliest-blooming, flowering in April-May. It also has the most named cultivars. Wild forms reach 30-60 cm. Some of the named selections include ‘Magnificum' (larger flowers than typical for the species; 50 cm), ‘Finesse' (narrower petals than typical for the species; 50 cm), ‘Goldcut' (single flowers on 60 cm stems), ‘Spring Beauty' (aka ‘Fruhlingspracht'; double flowers on 30 cm stems) and ‘Little Leo' (semi-double flowers; 40 cm).
Some cultivars of D. orientale include 'Magnificum' and 'Finesse'
‘Miss Mason' is perhaps the most popular leopard's-bane. It is a very old hybrid, probably derived from D. orientale and D. columnae. Plants reach 30 to 45 cm and are among the most reliable bloomers, always prolific with their floral production of single yellow flowers.
Blooming about 2 weeks after D. orientale is D. plantagineum, a species that may reach 60 to 80 cm. This one is slightly more tender than D. orientale, rated for zone 5. Its flowers are slightly larger. ‘Strahlengold' is a mildew-resistant, very floriferous selection.
Pictured above are 'Miss Mason' (left) and D. plantagineum (right)
Giants among the leopard's-bane are D. austriacum and D. pardalianches. These are often called ‘great leopard's-bane'. Both reach about 100 cm and have distinctly fuzzy foliage. They are the last Doronicum to bloom, mostly in June but sometimes into July. They may also repeat some blooms late in summer and early fall. Like D. plantagineum, these two are also rated for zone 5.
Above are the 'great leopard's-bane', D. pardalianches and D. austriacum
More obscure species well worth growing if obtainable are D. altaicum (30 cm; the hardiest species rated for zone 2), D. clusii (35 cm; zone 5), D. grandiflorum (35 cm; zone 5) and D. glaciale (most dwarf species to 20 cm; zone 5). All of these are wonderful subjects for a sunny rockery.
Wonderful rock garden subjects are D. clusii (left) and D. glaciale (right)
The culture of leopard's-bane is quite simple. They prefer evenly moist, organic-rich soil in sun to dappled shade. Soil pH does not appear to be an issue. Under hot or dry conditions, plants will go summer-dormant. The toxic nature of these plants makes them unpalatable to rabbits and deer. Leopard's-bane are useful for borders, woodland gardens, cut-flower gardens or rockeries (the smaller species and hybrids). Plants should be dead-headed immediately after flowering. This often stimulates them to produce a few blooms later in summer or early fall, especially D. pardalianches. To maintain the most vigorous plants, they should be dug and divided every 3 to 4 years. This is best done in early autumn. Besides division, plants may also be grown readily from seed.
If you don't currently grow any leopard's-bane, then I highly recommend you consider adding them to your garden. Their bright spring display is second to none!
I would like to thank "mainer" for the use of the picture of D. orientale 'Magnificum'.