This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
For backing up many flowers used in wreaths, crosses, bouquets, etc, it is sometimes essential to have foliage that will throw the blossoms into greater relief, and a large number of plants are grown for this purpose. Until the various kinds of Asparagus were introduced, the fronds of the Maidenhair Fern were used in enormous quantities for almost everything. Of late years, however, the foliage of other plants has been utilized, and florists now stock in the proper season the leaves of such plants as: Crotons, Maples, Holly-leaved Barberry (Berberis Aquifolium), Copper Beech, Ivy, Copper Hazel, Purple Plum, Scarlet Oak, Galax aphylla, large-leaved Myrtle, etc, to which must be added for winter work sprays of Mistletoe and of Holly in leaf and berry. There is still a great trade done in what is known as "French Fern" (Asplenium adiantum-niqrurri), the fronds of which are sold in bunches. The old conventional ideas, however, are gradually vanishing, and it is now customary to use the natural foliage of any flower that may be used in floral work. Thus violet leaves are most appropriately used with violet blossoms, as holly leaves are the most suitable adjuncts to the scarlet berries. Indeed there is no end to the methods employed by the modern florist to produce a charming effect; and the plant and flower grower who will introduce a new plant, or suggest a novel idea, is looked upon as a floral friend.