There is no mistaking the greenhouse in which a flowering gardenia is growing; as soon as the door is opened the scent is almost overpowering. This evergreen shrub bears its whitein spring, summer and autumn, and it is the double-flowered forms of Gardenia jasminoides which are usually grown. The best flowers are borne on one- to two-year-old specimens but older plants flower very freely. This is a lime-hating plant and if one is making up one’s own John Innes compost the ground limestone or chalk must be omitted. If the compost is bought, half as much peat should be added, measured by bulk.
The plants should be potted or planted in February or March and be pruned for shapeliness during the same two months. The temperature from September to March should be between 13 and 18°C. (55 and 65°F.), and from March to September 21 to 24°C. (70 to 75°F.). Water moderately in winter but more freely at other times with daily syringing except in winter or when the plants are in flower.
Once the plants are established in their final pots (of 5- or 6-in. size), feed once a week with liquid or soluble fertiliser in spring, summer and autumn and once a fortnight during the winter months. If a minimum temperature of 13°C. (55°F.) is maintained the plants will flower in winter as well.
Heel cuttings can be rooted in February in a propagating frame with a temperature of 21°C. (70°F.). When rooted, these are potted into 3-in. pots and then into 5- or 6-in. pots. Pinching out the growths once will make the plants bushy, and flowering is likely to occur later in the same year.