The lobelia which Burncoose offers are hardy clump forming perennials (and not annuals) but be careful not to get the milky sap from their broken stems onto your skin where it can cause serious irritation or a rash. Lobelia are extremely floriferous plants for the herbaceous border where they grow to different heights. These plants have strong flower colours and, in some cases, coloured leaves so you need to think carefully how to arrange the colour schemes in your border design to avoid colour clashes. All flower from midsummer on to early autumn and they thrive in moister soils in full sun. Damp conditions over winter will cause clumps to rot.
L. cardinalis propagates easily from softwood cuttings in summer. All our varieties will need tidying up when they finally go dormant in late autumn. A good mulch will improve their performance in the following year. L. tupa is hardier than other varieties but none should give much cause for concern over their frost hardiness except perhaps in the most severe winters when, again, the mulching will help. Clumps are best split and divided in the spring rather than the autumn.
L. cardinalis ‘Queen Victoria’, the cardinal flower, has reddish-purple stems and leaves and foot long racemes of flowers which are two-lipped and vivid red in colour. The overall height of the plant in flower can be up to 3ft but usually a bit less.
L. ‘Compton Pink’ has soft pink flowers with darker centres and grows to much the same size as ‘Queen Victoria’.
L. siphilitica, the blue cardinal flower, has 4-6in light green leaves and two-lipped bright blue flowers and leafy bracts. The flowers are borne in dense racemes of up to 15-18in long. The overall height of this species is about 2ft.
L. tupa is a much more robust grower and, when mature and fully flowering, it can grow up to 5 or 6ft. The plant by the conservatory at Burncoose is slow into growth in the spring but at its best in September. The flowers are narrowly tubular and red or orange-red with purple calyxes. The flower racemes can be 18in in length. The plant bulks up more slowly as a clump than other lobelia.