This genus includes the ever-popular hardynasturtium (Tropaeolum majus), canary creeper (T. peregrinum) and the Scotch flame flower (T. speciosum). Nasturtiums do best on thin, sandy soils, as on rich land they are apt to make foliage at the expense of . The semi-double Gleam varieties grow to about 16 in. They are of trailing habit, throwing out short runners. The fragrant blooms come on fairly long held well above the and are excellent for . Varieties include Golden Gleam, Mahogany Gleam, Orange Gleam, Gleam, Salmon Gleam and Scarlet Gleam. Fiery Festival is a luminous geranium-scarlet; Golden Globe is more compact with no runners. Mixed hybrids are available, as well as a semi-double strain growing to about 10 in. This includes shades of orange, gold, crimson, scarlet, maroon, salmon etc. There are also single and double varieties with dark foliage, and climbing nasturtiums which are suitable for clothing tree trunks, trellis work, old walls etc. Keep a watch for black fly on all tropaeolum and dust with gamma-BHC. Tropaeolum peregrinum (canary creeper) is an extremely rapid annual climber to about 10 ft. It bears small yellow flowers and is useful for covering an unsightly fence, shed etc., tolerating some shade, unlike other nasturtiums.
The perennial T. speciosum (Scotch flame flower or Scotch creeper) is often seen flourishing in cottage gardens in the north and Scotland. Elsewhere it is unreliable although there is a good chance of success if the following points are noted. Plant in a bed of cool soil enriched with peat andmould at the foot of a north wall or better still, on the north side of an evergreen hedge such as yew, the main object being to protect etc. from hot sunshine. The scarlet flowers are followed by the red capsules containing the large blue , the light green leaves forming a pleasing contrast. Never allow this plant to become dry at the roots.
T. polyphyllum is tuberous-rooted and does particularly well on a hot, sunny bank. Perfectis essential. It is of prostrate habit with grey-green foliage and thick bearing vivid yellow or orange flowers.