Chapter 14 details the main methods used by ornamental horticulturists for reproducing plants. Greenhouse production uses some reproduction methods more than others for particular purposes:
• seed for production of bedding plants and geraniums
• runners for foliage plants like the spider plant
• bulbs for flowering perennials like tulips, daffodils, crocuses, and gladioli
• layering for foliage plants like the fig and rubber plant
• cuttings for geraniums, chrysanthemums, and many foliage plants
figure 20-8. Mums are a common plant that is begun by rooted cuttings and then transferred to pots for continued growth. (Delmar/Cengage Learning. Photo by Ed Reiley.)
• grafting for some azaleas
• budding for roses
• division of the crown for foliage plants and African violets
• tissue and organ culturing for orchids and bromeliads, and for production of disease-free stock for chrysanthemums, carnations, and other flowering plants
The greenhouse grower may propagate the crops and grow them to maturity, or buy cuttings and other propagative stock from firms that specialize in propagation. Of the numerous methods of reproduction used by greenhouse growers, seeds and cuttings are the most common (Figure 20-8). Despite the comparative ease of propagation by cuttings, many species are protected by plant patents that require new cuttings to be purchased each time from the supplier.
