This herbaceous perennial is a very old flower in this country; it came
from Carniola in the year 1594. It is very hardy, and for several months
together it continues to produce its large lively blue flowers,
beginning in July and lasting until stopped by frosts. At no time is it
in finer form than in September; at the height of from 5ft. to 7ft. it
proves richly effective amongst the blooming hollyhocks, where, as
regards colour, it supplies the "missing link" (see Fig. 23).
The flowers are a light bright blue colour, and 1in. to 1½in. across.
The corolla is bell-shaped, the five divisions being deeply cut, which
allows the flower to expand well; the calyx is neat and smooth, the
segments long and awl-shaped; the flower stalks are short, causing the
numerous erect branches to be closely furnished with bloom during
favourable weather. The leaves of the root are very large and stalked,
of irregular shape, but for the most part broadly oval or lance-shaped.
The edges are slightly toothed, having minute glands; those of the stems
are much smaller, sessile, and long egg-shaped; all the foliage is[Pg 52]
smooth, and of a dark green colour; the main stems are very stout, and
sometimes grow to the height of 7ft. Vigorous plants will send up
several of these, from which a great number of small ones issue, all
assuming an erect habit; blooming specimens are hardly anything else
than a wand-like set of flowered stems, and though it is advisable to
stake them, I have seen them bend and wave during high winds without
damage.
In the borders and shrubbery this is a very effective subject; it is
amongst herbaceous plants what the Lombardy poplar is amongst forest
trees—tall, elegant, and distinct. Its use, however, is somewhat
limited, owing to the stiffness of the stems and the shortness of the
flower stalks; but when grown in pots—as it often is—for indoor
decoration, it proves useful for standing amongst orange and camellia
trees. It has very strong tap roots, and enjoys a deep rich loam. Not
only does it look well among trees, but otherwise the partial shade of
such quarters seems conducive to finer bloom.
C. p. alba is a white flowering variety of the above species; its
other points of distinction are its smaller-sized leaves and much paler
green colour, by which alone the plants may be easily recognised from
the type. This variety may be grown with good effect in pots or the
border; it scarcely gets so tall as the blue form, but looks well by the
side of it.
The readiest way to increase these plants is to take the young and dwarf
growths from the woody crown of the roots, paring off a little of the
bark with each. If these are put in sandy loam during the warm growing
season and kept shaded for a few days, they will very soon make plenty
of roots; this method in no way damages the flowers. Another way is by
seed, but seedlings are two years before they bloom.