This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Adexophora is a genus closely resembling, in all superficial features, Campanula, from which it was separated on account of the glandular cylindrical tube or disc that surrounds the base of the style. The generic synonym Campanula is therefore common to all the species, and under that name they are sometimes circulated in Continental lists. They are very useful hardy herbaceous plants, but possessing very little variety of colour, stature, and habit - blue, in lighter and darker tints, being the colour of all. They will be found most useful for the shrubbery and mixed border, and are easily cultivated in almost any kind of garden soil, if not wet and stagnant.
Adexophora Liliifolia is perhaps the best and most useful species in the family. It grows to the height of about 2 feet or 2 1/2 feet, with narrow lanceolate leaves and rather erect stems, terminating in panicles of pale-blue flowers, which appear in the end of May, and last till the middle or end of September. Native of Siberia and Dahuria.
Adexophora Suaveolens reaches the height of about 2 feet, with erect stems and spreading terminal panicles of pale-blue flowers, appearing in June and July, often also throughout August. Native of Siberia. This species appears to be a dwarf and more compact form of the Adexophora communis from the same country, but a taller and coarser plant every way than the Adexophora suaveolens. It is also sometimes confounded with Adexophora liliifolia and vice versa, from which, however, it is distinct; and at present in this country it is more plentiful.