Lobelia x gerardii
The Blue Lobelia that most gardeners know is a tiny edging plant that is unparalleled for its intensity of blue. There are few other flowers that can match it. Now imagine the same blue-coloured flowers, only larger and borne on 90cm tall flowering spikes. This is the Lobelia x Gerardii and it is simply breathtaking in a mixed border.
The Lobelia x Gerardii is a garden hybrid originating from the Eastern USA and Canada, and is a cross between Lobelia Siphilitica (which bears blue flowers) and Lobelia Cardinalis (which bears red flowers). It is a low-growing, clump-forming perennial that starts flowering in early summer and continues throughout summer.
The masses of flowers are purple-blue, with some darker than others. As is the case with most perennial Lobelias, it likes a moist but well-drained soil and, although it is said to grow in full sun or semi-shade, in hotter areas it is more suited to semi-shaded areas whereas in the cooler mountainous areas it can be grown in full sun.
It is excellent as an accent or border plant and even for mass planting in a large garden. It can be propagated from seed, cuttings or root division in late autumn, with plants grown from seed performing better in their second year.