Plant Portraits: Digitalis sceptrum

Digitalis sceptrum, July 2013

For the most part, the experience of gardening is a succession of small triumphs and minor failures, all of which make us stronger people and better gardeners.  Of course our patience is sometimes tried by storm and pestilence, then just occasionally we get to enjoy a major achievement.

It may not be a big deal to anyone else, but at long last my Digitalis sceptrum (formerly Isoplexis sceptrum) has flowered. It’s been a five year wait and at times I doubted it would happen, but now that it has I am very proud of myself.  The photograph above was taken on July 13th 2013 as the flowers started to emerge from the emerald green foliage.

Two species of Isoplexis were originally identified by Linneaus in 1753 as being part of the genus Digitalis, which also gives us our humble native foxglove Digitalis purpurea.  The two species were Isoplexis sceptrum and Isoplexis canariensis.  Since 1753 Isoplexis has been moved around endlessly in botanical terms, but in 1999 was finally proven to be a true Digitalis.  I think I’ll always prefer Linneaus’ name for sounding like a new type of plastic or rehydrating drink!

Both species grow in woody habitats in Madeira and will grow outdoors in milder parts of the UK, like fellow natives Echium pininana and Geranium maderense.  In the wild, D. canariensis favours  humid woodland whilst D. sceptrum inhabits cloud forest, growing near streams and on steep slopes.  In our seaside garden the latter grows at the front of a raised bed, where the drainage is sharp and it catches the sun for a few hours each day.  My experience is that D. sceptrum tolerates frost and cold very much better than Echium pininana, retaining green, fresh foliage throughout the worst of the winter.  Unlike Echiums,  D. sceptrum can also grow well in a pot, making it accessible to anyone with an unheated greenhouse or conservatory.

Leaves are produced year-round, with older ones turning yellow and dropping in spring.  My first flowers are appearing now, in July, but might perhaps emerge earlier given some decent spring weather.

Digitalis sceptrum, July 2013

The flowers of both species are adapted for bird pollination in their natural habitat, although our sparrows have shown no interest so far in their sweet nectar! The blooms bear more than a passing resemblance to our native foxglove and the fashionable but small-flowered rusty foxglove, Digitalis ferruginea.  The spikes emerge about 10 inches long and are topped by downward facing, rusty orange flowers beautifully netted with chocolate brown. The top of the spike is rather like a pineapple – long acid green leaflets forming an attractive topknot.

I’ve been told that D. sceptrum responds well to pruning after flowering or being cut back by frost, forming several new shoots.  Mine however is producing a neat, rounded bush about 75cm tall without any help.  It might eventually attain about 120cm, by which time it will have outgrown its current space.  In the wilds of Madeira, where this is an increasingly rare plant, D. sceptrum forms an umbrella-shaped small tree about 4 metres high.  The photograph below is credited to Mapa-73, showing a specimen much larger than mine – perhaps in a couple of years’ time I’ll be able to get a similar shot.

Isoplexis sceptrum

If you are a patient gardener with a thirst for the exotic I’d thoroughly recommend giving D. sceptrum a try.  As well as being beautiful, it’s also amazingly pest and disease resistant.  Mine has never entertained so much as an aphid and looks healthy and presentable year-round.   Perhaps in its natural home it suffers, but clearly with bugs that don’t travel well.

I purchased my plant from Hardy Exotics in Cornwall, by mail order following a visit (the car was already too full of plants to squeeze another in!) and I would highly recommend this nursery as a source of all things wild and tropical looking.  Nothing I bought from them has ever failed.

I’d love to hear your experiences of growing this fabulous plant, so please leave a comment below with any comments, hints or tips.