Foxgloves

14. June 2020 by Isabelle Van Groeningen
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Foxgloves - Digitalis opportunisten © Isabelle Van Groeningen
Foxgloves – Digitalis opportunisten

– zur deutschen Version – One of our most charming wildflowers are without doubt the foxgloves. This is the time of year when their impressive tall flower stems, clad with luminous purple nodding flowers bring great drama to shadier areas. These are much loved by a variety of bees and bumblebees who busily crawl deep into the spotted throats of the pendulous thimbles. The botanical name Digitalis, comes from the Latin digitus, or finger.

Opportunists

Our lovely foxgloves are not alone: There are about 25 different species, many of which occur in Europe and the near east, mostly in woodland clearings or along woodland margins in partial shade. They are true opportunists: they make themselves at home there where sufficient light is available, and where they have enough space to grow and develop. Where a tree falls down, they will quickly colonise the area, making the most of the extra light. As neighbouring plants start to encroach again, they will move to a new area.  This way communities can migrate through the garden as conditions change.

Plant two years after another!

Most Foxgloves are biennial or short-lived perennials. This is important to remember. So often garden owners complain that their plants have disappeared, not realizing that this is normal. In the first season the plant develops a rosette of leaves, the following spring a flower spike will emerge from this rosette. After the seeds have set and ripened, most plants will die. Their seeds are scattered and will germinate and develop into a new rosette the following year. Therefore, it is important to plant them two years in a row in order to establish two parallel communities.

Toxins of foxgloves

Digitalis is a poisonous plant, but as with many poisonous plants, when the poison is administered in the right dose, it becomes a cure. They contain several substances, but the most relevant to both traditional herbal and modern medicine are the glycosides Digoxin (extracted from Digitalis lanata)  and Digitoxin (extracted from Digitalis purpurea). They are widely used as medication to treat heart conditions.

Foxgloves - Digitalis purpurea © Isabelle Van Groeningen
Digitalis purpurea

Digitalis purpurea – Common Foxglove

This is the best known one. The tall flower spikes, reaching 1,8 to 2m in height are truly biennial. The most common form is purple, but paler pink to white forms occur too. If you want to have (and keep) white flowers you have weed out all purple ones as soon as they start flowering.  White is genetically recessive, so that in mixed communities, the bees will spread pollen from purple flowers. The result is an ever-increasing proportion of purple seedlings.

They occur on acid soils in association with woodlands throughout Western Europe, from Portugal, France, Belgium Netherlands, western Germany, the British Isles to Norway.

Digitalis grandiflora – Large Yellow Foxglove

Foxgloves - Digitalis grandiflora © Isabelle Van Groeningen
FoxDigitalis grandiflora

The flowers are almost as large as those of the more common Digitalis purpurea but scattered much more loosely along the flowering stem, reaching 0,70 to 1,20m in height.  The soft, pale yellow colour is an appealing colour for the garden, but the plant does not add the drama that common foxgloves create.

From the Alps, spreading north-east through Germany, Poland, Austria, reaching as far east as Siberia, they are often seen springing up on recently deforested slopes. 

Digitalis lutea – Straw Foxglove  

Foxgloves - Digitalis lutea © Isabelle Van Groeningen
Digitalis lutea

Barely reaching one meter, this is a dainty, elegant plant that normally occurs along woodland edges in more calcareous soils. The slender flowers are a pale, sulphur yellow colour, that can be used in many different colour combinations. It originates from France, Switzerland and Italy across to north Africa.

Digitalis ferruginea – Rusty Foxglove

Foxgloeves - Digitalis ferruginea © Isabelle Van Groeningen
Digitalis ferruginea

This biennial or short-lived perennial grows naturally in Italy, Croatia into Turkey, down to Syria and Lebanon. It will tolerate partial shade, and acid, as well as slightly alkaline soils.  It grows to about 1.2m in height, from a rosette of narrow basal leaves with tightly packed flowerspikes of rusty coloured small flowers. Of all the species described here, I find this one creates the best silhouette in a planting, with its pointed, slender erect outline. 

Hybrids

Over the years, a number of hybrids have been raised. Digitalis purpurea ‘Alba’ is a naturally occurring white form, with the usual dark spots in the flower’s throat. A pure white form, devoid of any markings is ‘Lucas White’. Digitalis purpurea ssp. heywoodii ‘Siler Fox’ has beautiful silvery foliage, topped with the purest white Flowers. This is smaller and more delicate than the normal foxgloves. 

Digitalis ‘Pam’s Split’ has split petals, creating an unusual effect. ‘Polkadot Polly’ has a soft apricot colour with numerous small dots, whereas ‘Limoncello’, which I first discovered at the Chelsea Flower Show three years ago, has refreshing pale lemon-yellow flowers. We added it to our herbaceous border this summer as one of the “annual gap-fillers” we use to enhance the flowering season throughout the borders. ‘Beauty of Roundhay’ is a sterile hybrid with rather delicate, slender flowers, which is more reliably perennial than most others.

Digiplexis

Fingergut - Digitalis 'Glory of Roundway' © Isabelle Van Groeningen
Digitalis ‘Glory of Roundway’

A new intergeneric hybrid was raised a few years ago between Digitalis and a tender relative form the Canary Islands Isoplexis. The result is a long-flowering Foxglove-like plant with warm colours. Sadly, the hardiness gene of Digitalis seems to have been the recessive one. But as it is such a long, prolific flowerer, one can forgive its frost-sensitivity.

Propagating Foxgloves

Fingerhüte selbstaussähend © Isabelle Van Groeningen
Fingerhut selbstaussähend

Most are easily grown from seed. I like to raise my seedlings in pots, until large enough to be planted out. This way I can monitor their watering requirements closely, and keep an eye out for possible pests and diseases (slugs may be an issue with young plants.) It is possible to plant them, with the hope that they will self-seed. The success of this less predictable, and you have no control of where they will appear. 

Have a go at this delightful genus – it always puts a smile on my face!

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