Foxglove - A 'Foxy' Flower for Shady Gardens

GardenLine | Yard & Garden | Foxglove - A 'Foxy' Flower for Shady Gardens

Brian Baldwin

Of the limited number of flowers that perform well in shade, fewer still are large and showy. One of the best flowers available for shade is foxglove (Digitalis). Where several of these old-fashioned flower are grouped toward the back of a dimly lit spot, their bold 45 to 120 cm floral spikes almost seem to radiate light, bringing life to what could otherwise be a colourless site. Flower colours range from white, yellow, pink, rose, lavender, and purple, and in all cases the individual flowers are about the size and shape of a thimble. On each thimble, one inside wall is mottled by crimson, burgundy or chocolate spots, set in the centre of a larger white spot creating an extremely handsome effect.

Folklore suggests that this plant was originally called "folk's glove," with "folks" referring to the little people or fairies of the woodlands. A variation on that theme suggests that the forest's little people distributed these flowers to foxes to wear as gloves during raids on chicken coops. The idea probably held some appeal to the local farm population, as a gloved fox could easily be held responsible for any raids where the culprit escaped without a trace. A third suggestion for the name is based upon "fox's glew," with glew being an ancient musical instrument to which the flowers bore a resemblance.

The origin of the botanical name, Digitalis, is more certain; it is based upon the Latin word digitatus for finger. This is because the thimble-like blossoms fit a human finger almost perfectly.

With such distinct thimble-like qualities, a child would almost certainly feel obliged to poke a finger inside the flower. While this act alone is not unsafe, parents should be warned that all parts of the foxglove plant contain highly toxic alkaloids. In fact, the woolly foxglove (Digitalis lanata) is commercially grown as the source of digoxin, the widely- used heart drug which is administered to strengthen or normalize an irregular heart beat. The common foxglove of flower gardens (Digitalis purpurea) contains digitoxin which is also poisonous, but not widely used as a heart drug.

Common foxglove is biennial. Since biennial plants live for two growing seasons, but flower only in the second, survival of the first winter is crucial for flowering. This is a major problem for prairie gardeners as our winters are somewhat more formidable than those the plant would face in its native habitat of Europe, western Asia and northern Africa. To overcome the problem of winter losses, the `Foxy' strain of foxglove was developed. Unlike most biennials, `Foxy' flowers during its first growing season. It can therefore be treated as an annual - or if you are lucky enough to have it survive the winter - as a biennial. The plants are said to prefer acid soil, but seem to do well on our less-acidic prairie soils. Because of their tall floral spikes, they also benefit from a somewhat sheltered location where they are protected from wind. On more exposed sites, plants can be staked. A spike that is blown over will usually continue to flower along the ground, but will turn abruptly upward near its end, giving it an undesirably contorted form.

Because they require a growing season of five or more months to fully complete their blooming, seedlings of `Foxy' should be started in early winter and maintained in a greenhouse until spring transplanting. Or, well-established seedlings may be purchased in spring. Since these seedlings are usually sold in the nursery's perennial section, however, they can represent a somewhat pricey bedding plant if used in large numbers.

In regions where the growing season is at least 150 days, the plants will set large quantities of seeds and naturalize in ditches and other non-mowed spaces. Since our season is usually not quite long enough to permit volunteer seedlings to complete their full life cycle, your chances of getting a `Foxy' foxglove to survive a second season is best if you remove the flower stalks immediately upon completion of the first season's flowering. This will halt the movement of energy toward seed production, and focus energy where it will promote winter survival. Mulching will also be beneficial where an early reliable snow cover is not assured.

Only one type of foxglove survives reliably as a perennial on the prairies. The perennial foxglove is known as either Digitalis grandiflora or Digitalis ambigua, and flowers in June, producing multiple spikes of butter-yellow thimble-shaped flowers with brown to purple markings in the throats. Flowering spikes reach about 100 cm and bloom for several weeks. A hybrid perennial foxglove was produced by the late Dr. Frank Skinner and named `Dropmore Yellow.' The plant is attractive and reliable, yet remains an infrequently seen specimen in prairie gardens. If you're lucky enough to know someone with this plant, you may wish to remind them that it can be propagated either by seed or careful division in spring.

Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.