This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
This Japanese shrub is largely forced into early bloom during the winter months, and is valued for sprays of pure-white flowers. It is raised from cuttings or layers in the open air or in cold frames, and when the plants are well established, and large enough, they are lifted and potted in early autumn, and placed in frames. From November onwards batches are introduced to a warm greenhouse as required, and growth is promoted by daily syringings and watering until the flowers appear. The plants are then placed in a cooler place to become hardened off for market. Old plants, if pruned hard back after flowering, will throw out strong young shoots for blooming the following season. Deutzias flourish in a loamy soil with a little sand and well-rotted manure or leaf mould. Such kinds as crenata, discolor, parviflora, and the hybrid Lemoinei are stocked by nurserymen.