Ipomoea tricolor: Morning Glory
Most species belonging to the family Convolvulaceae are grown as annuals and are often planted in window boxes, but many are perennial, including members of the genus Ipomoea. When one considers that it includes some 400 species distributed chiefly in tropical America, then it is evident that it offers countless opportunities for growers.
Ipomoea tricolor (syn. Pharbitis rubro-coerulea) does best if grown in a window-box in rich, well-drained compost, such as John Innes potting compost No. 2 and full sun. Similarly cultivated are other beautiful species, for instance Ipomoea hederacea with pale blue; I. Nil with flowers varying in colour from pale blue to deep purple; and I. purpurea, which besides the purple form occurs in many lovely colour deviations.
Perennial species are readily grown in warm, cen-trally-heated homes in rather heavy, rich compost, such as that already mentioned, in full sun or in a lightly shaded spot by a window. Ipomoea horsfalliae has a profusion of beautiful pink flowers (particularly ‘Lady Briggs’) and palmate leaves; I. learii has many-flowered clusters of rose-purple blooms edged with pale blue and measuring about 10 cm (4 in) across. I. Purga with its large, deep pink to red flowers is also beautiful, and excellent for a sandy spot beside water in the paludarium is I. pescaprae with leaves cut out at the tip and large deep pink flowers. All the species can be readily propagated by cuttings.
A special group is formed by the xerophilous species, for example Ipomoea arborescens from Mexico — a tree reaching a height of up to 4 m (13 ft) in the wild (but much smaller in cultivation) with large white flowers; and I. stans, likewise from Mexico, which is of shrub-like habit with a short stem, but with a large underground woody rhizome and pink flowers. These species should be grown in full sun in poor, stonyand kept in a cool spot without water during the winter rest period.