Boronias are the most delightful evergreen plants with very fragrant flowers but they are most definitely frost free greenhouse or conservatory plants even if they do go outside in pots on the patio for the summer months.
Boronia megastigma may survive the occasional frost in a sheltered border. Boronia heterophylla, which perhaps looks more robust at first sight, will not tolerate any frost.
Boronias are Australian plants which grow in the wild on sandy heaths and the edges of woodland. B. heterophylla has pink bell shaped flowers while B. megastigma and B. crenulata have more cup shaped flowers.
These plants require ericaceous compost (ie no lime) and like to be in well lit rather than shady areas although their leaves can scorch in the greenhouse without some sun shading or protection.
No pruning is necessary but B. heterophylla grows quickly and can be chopped back each year when potted on. Liquid fertiliser should be applied monthly in the growing season and the plants need to be watered sparingly over winter.
Cuttings root easily in a mist bench with bottom heat when taken from the semi-ripe new growth in summer.
Boronias can be susceptible to the pests which are often a problem in the greenhouse. Most notably red spider mite.
