Which Plants to Grow in Different Types of Greenhouses
Plants to Grow
A greenhouse greatly enlarges the scope of your gardening, but it is important to decide on the warmth you can provide and the type of crops or plants you wish to grow.
For convenience it is usual to break down the temperature ranges for a greenhouse into three groups, depending on the minimum night temperature that can be maintained:
Cool greenhouse: 7°C (45°F)
Warm greenhouse: 16°C (60°F)
Having settled on the temperature range which should be maintained even in the most severe weather it is possible to consider the best plants to grow.
Normally no artificial heat is used, protection being provided by blinds, mats or newspapers if necessary in very cold weather. Double glazing reduces heat loss, but is expensive and cuts down light at a crucial time of year. Lining with polythene may, however, be of benefit provided condensation does not become a problem in consequence.
The limitations of temperature mean that the plants you can have in flower in winter will be confined mainly to those that bloom naturally at that time, and in the early spring months.
Spring-flowering plants to grow include: juliae, P. allionii, auriculas, pansies ( x wittrockiana), violets (Viola spp), saxifragas, Kaffir (Schizostylis coccinea), and many bulbous subjects such as crocuses (Crocus spp), cyclamen, (Narcissus spp), fritillarias, hyacinths (Hyacinthus), irises, narcissi and snowdrops (Galanthus nivalis).
Showy flowering shrubs in pots include brooms such askewensis and C. praecox, forsythias, heathers (Erica carnea, now more correctly E. herbacea), and carlesii.
Summer-flowering plants to grow include: annual plants in variety, cannas, carnations (Dianthus caryophyllus),, , and verbena. Summer-flowering bulbs include hot (Achimenes spp), African corn lilies (Ixia spp), African harlequin flowers (Sparaxis spp), and vallotas.
Summer-flowering shrubs to grow include Hibiscus syriacus, fatsias, prickly heaths (Pernettya mucronata), roses (Rosa spp) and hydrangeas.
Autumn-flowering plants to grow include: perpetual carnations (Dianthus caryophyllus), eucomis, nerines, yellow star flowers (Sternbergia lutea), tritonias, and the Kaffir lilies (Schizostylis coccinea). The Chilean bellflower (Lapageriarosea) and the passion flower (Passiflora caerulea) are good .
Winter-flowering plants to grow include:(Helleborus niger), Viburnum fragrans (synV. Farreri ), winter jasmine ( ), and a wide range of bulbs including reticulata and I. Danfordiae.
Provided a minimum winter temperature of 7°C (45°F) can be maintained, :here is an almost unlimited supply of plants and shrubby subjects available which will ensure the cool greenhouse is always colourful and interesting.
A collection to provide year-round colour should include (A. indica), (both fibrous and tuberous types for flower and B. rex for foliage), the slipper flowers (Calceolaria spp), cannas, , cinerarias (Senecio cruentus), flame nettles (Coleus blumei), cyclamen, heaths (Erica hiemalis and E. gracilis), fuchsias, macrophylla, busy Lizzies (Impatiens spp), kalanchoe (particularly K. carneo, K flammea, and K. blossfeldiana ), Chilean bellflower (Lapageria rosea), pelargoniums, primulas (P. obconica, P. malacoides, P. sinensis, and P. kewensis), and the ever-popular African violet (Saintpaulia ionantha).
A warm greenhouse, where 16°C (60°F) can be maintained, is suitable for all the plants suggested for the cool house, plus many other beautiful plants.
The flamingo plant (Anthurium andreanum) has interesting flowers in shades of pink and red, and often decorative leaves. Aphelandra squarrosa also has handsome leaves and flowers.
Cymbidiums are among the easiest orchids to cultivate, and are well worth growing for their lovely flowers from March to May; they like a peatyand plenty of moisture during the growing season.
Caladiums and Cordyline terminalis (now C. fruticosa) are both notable for their coloured foliage.
Crossandras, which come in several colours, can produce spikes of flowers with showy bracts for most of the year, while Columnea banksii freely produces its brilliant red flowers on trailing stems throughout summer.
Also noteworthy for simple warm greenhouse culture are Jacobinia pauciflora, scarlet and yellow; Jacaranda ovalifolia, with-like leaves and lavender-blue flowers; Boronia mega-stigma, fragrant foliage; Hibiscus rosasinensis, rose-red; and Streptosolen jamesonii, an evergreen climber with orange-red flowers.