Herbaceous Plants

Clarkia tenella (Cav.) F.H. & M.E.Lewis

Frost tender, erect, sometimes decumbent, perennial with branched stems, elliptical leaves to 6cm, and lavender to blue or deep red-purple flowers in summer.  To 50cm.  [RHSD].

Clematis heracleifolia DC.

This is a hardy, herbaceous, woody-based perennial of open habit with toothed, deeply 3-lobed leaves and scented, tubular, purple flowers, produced in whorled racemes in summer.  [RHSE, Hortus, Don].

Clitoria ternatea L.

Frost tender, slender, evergreen, short-lived perennial twiner with pinnate leaves composed of 5 leaflets, and usually solitary flowers, each 2.5cm long, clear blue in colour, marked on the standard with yellowish white.  The flowers are somewhat variable in markings and white and double-flowered forms are known.  To 4m.  [RHSE, Hortus].

Cobaea scandens Cav.

Frost tender, very vigorous, evergreen, perennial climber, with fragrant flowers, opening white and ageing to purple, from summer to autumn.  To 20m.  [RHSE, Hortus].

Columnea scandens L.

Frost-tender trailing sub-shrub with 5cm long leaves, with red hairs at the margin, and sparsely hairy, red or yellow flowers, singly or in pairs, from spring to summer.  To 15cm, trailing to 1m.  [RHSE].

Columnea schiedeana Schltdl.

Frost-tender trailing shrub or climber with dark green leaves, crimson beneath, and numerous long yellow-brown flowers, blotched and banded dark red, all along its stems, which tend to root at the joints.  [RHSD].

Consolida ambigua (L.) P.W.Ball & Heyw.

Fully hardy annual with fern-like leaves and tall spires of flowers in pink, white or violet-blue.  Many garden cultivars exist.  To 1.2m.  [RHSE, Hortus].

Convolvulus althaeoides L.

Fully hardy, vigorous, slender, climbing or trailing perennial with heart-shaped, lobed, hairy, silvery-green leaves and axillary clusters of 1-3 widely funnel-shaped, clear pink flowers to 4cm across, in summer.  To 15 cm.  [RHSE, Hortus].

Convolvulus tricolor L.

Fully hardy, bushy, upright, then spreading perennial, usually grown as an annual, with funnel-shaped royal-blue flowers with a lighter centre in succession throughout summer.  Many cultivars are available.  To 40cm.  A very useful bedding and edging plant.  [RHSE, Hortus].

Coreopsis lanceolata L.

Fully hardy, clump-forming perennial with upright, solitary flower heads with brighr yellow daisy-like flowers from late spring to mid-summer.  To 60cm.  [RHSE, Hortus].

Coreopsis tinctoria Nutt.

Fully hardy erect annual, bearing solitary, bright yellow flower heads, shading to brown red at the bases.  Darker colour variants are available.  In early Victorian gardens the darker flowered forms, in shades of scarlet purple, edged with yellow, were often known as Calliopsis bicolor.  To 1.2m.  [RHSE, Hortus].

Cymbopogon schoenanthus (L.) Spreng.

Frost tender tufted grass with erect stems and a much-branched, ornamental inflorescence.  To 30cm.  [RHSD, Hortus].

Cyperus papyrus L.

A frost tender, stout perennial reed, the leaves in a drooping umbel at the top of the stem.  To 3m.  [RHSD, Hortus].

Datura metel L.

Datura metel is a frost tender annual species with greenish stems in yellow-flowered plants and purplish in darker forms, and upright, dark purple, blue, white or yellow trumpet-shaped flowers, white to pale violet inside, frequently double or triple, in summer.  To 1.5m. [RHSD, Hortus]. Fastuosa has dark foliage and double or triple flowers, purple on the outside, paler within.

The RHSD [1951] commented that Datura fastuosa was perhaps a hybrid of D. cornigera with D. chlorantha but I have not seen this substantiated.  

Datura metel L. var. elegans

See Datura metel L. for a discussion of the species.  Datura metel is a variable species, this is probably a cultivar or form with improved flowers.  I have found no specific description.