This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Perhaps the Balsam (see p. 133) is the best-known member of this genus, but there are a few other species worthy of note, especially I. Sultani and I. Hawkeri - both lovely bushy plants with bright-red flowers. They are easily raised from seeds or from cuttings, and require warm-house treatment, and a good loamy soil with a dash of sand and a fair sprinkling of leaf mould. Of late years a much more vigorous species - I. Oliveri, from Central Africa - has attracted some attention, and has been used for bedding out during the summer months. It may be grown like the other kinds, and will attain a height of 5 to 6 ft., making fine bushy plants covered with large pink, pale rose, or almost white flowers as large as a crown. Handsome little bushy specimens can be obtained in 5-in. pots.