Plant of the Month: August

Lobelia tupa Common name: devil's tobacco Family: Campanulaceae Vital statistics Height and spread: Up to 2m (6ft) high by 90cm (3ft) wide Form: Clump-forming perennial Soil: Deep, fertile, moist soil Aspect: Full sun to partial shade Hardiness: Hardy in some regions; need frost-free protection in winter

Along with many other Lobelia species and cultivars, L. tupa thrives at Rosemoor and is well represented throughout the garden.  A particularly attractive orange-flowered form has been selected and can be seen with its terracotta flowered cousins growing in both the Plantsman's Garden and Lady Anne's Croquet Lawn Garden.

Genus Lobelia
With over 300 species Lobelia shows a huge diversity of habit and form from montane trees through to a range of perennials of varying hardiness to small species commonly grown as annuals.

Lobelia species are found world-wide in tropical and temperate areas but especially in North, Central and South America where their habitats range from marshes, wet meadows and riverbanks to woodlands, hilly and mountainous slopes and desert.

Notably 2 Lobelia species are native to Europe and occur in England. L. urens occurs in rough pasture, on grassy heaths and at the margins of woodland, on damp acid soils from Cornwall to Hampshire and East Sussex.  L. dortmanna is an aquatic species found in stony lakes and tarns with acid water and is locally common in Wales, the Lake District and most of Scotland and Ireland.

Lobelias are valued for their often brightly coloured flowers which are unusually twisted through 180° and the style will push through the anther tube thus forcing out the pollen and ensuring that when the stigmas separate the receptive surface will be pollen free and so ensure cross pollination.

Perennial Lobelia species make good herbaceous border plants while the annual species are often used in bedding and hanging baskets or window boxes.  Aquatic species make ideal plants for ponds and pools.  Care should be taken when growing any Lobelia species in any situation as the acrid, milky sap may irritate the skin.

Lobelia was named by Linneaus after Matthias de l'Obel (1538-1616) a Flemish botanist and physician to King James I of England.

Lobelia tupa
A native to Chile Lobelia tupa is one of the hardier Lobelia species being able to withstand temperatures of -10°C over winter.

Lobelia tupa is grown for its beautifully felted leaves and narrow tubular brick-red to orange flowers which are borne from mid or late summer in racemes up to 45cm long.  It is naturally robust, upright, clump-forming perennial with attractive red-purple stems and lance-shaped, downy, grey-green leaves.

Cultivation
Lobelia tupa should be grown in full sun in an open position, with some shelter from the wind.  The soil should be deep, fertile and permanently moist.

To aid establishment and to help ensure survival in frost prone areas Lobelia tupa should be protected over the winter months with a dry bracken mulch.

Lobelia tupa is relatively free from pests and diseases though like most herbaceous plants the crowns may be attacked by slugs.  In mild damp winters the crown is susceptible to crown rot.

Propagation
Propagate by fresh seed in the autumn, sown at 15°C, and overwintered in a frost free frame.  It should be remembered however that Lobelia species readily hybridise and may not come true.

Lobelia tupa rosettes can be divided in the spring though in cold areas they should be lifted in the autumn and potted up in a cold frame as insurance against winter losses.