Impatiens walleriana

Impatiens walleriana in the garden of Leonie Furnell, Central Coast NSW

Often known as 'busy Lizzie', this succulent-stemmed, frost-sensitive perennial (ht 30-60 cm) comes from Tropical East Africa and is often treated as an annual in the Sydney climate. It has soft, fresh green leaves and simple, flattish flowers in a range of colours including white, pinks, salmon, red, purple, crimson, orange and lavender. It is an excellent plant for shaded or part-shade areas, and it will often self-seed when it is happy. There are some double forms that look like little roses - these do not self-seed. The plant blooms for many months from late spring to late autumn. It does best in soil amended with compost and kept reasonably moist. Pinching out the growing tips will help keep the plant compact, as will occasional pruning. Plants may survive a few years if in a sheltered position, protected from winter cold. Liquid fertiliser will enhance blooming.

For a number of years, Impatiens walleriana basically vanished from our gardens, due to 'Impatiens downy mildew', caused by the pathogen Plasmopara obducens, which became widespread in the world in 2011, and which causes the plants suddenly to lose their leaves and die. The pathogen seemed to be resistant to available fungicides. The plants no longer were no longer available in nurseries and the future for them looked grim.

Double form of Impatiens walleriana

Double form of Impatiens walleriana

However, it seems that they are back! Work by various breeders around the world over past decade has led to the development of strains that are apparently resistant to the dreaded mildew. Now some of these are available at nurseries here, in a range of pretty colours, which is great news for those who have always loved these humble yet rewarding plants. It is said that these new-generation plants still have a lengthy flowering season and need little care.

White Impatiens walleriana in the garden of Jill Fraumeni in Sydney

White Impatiens walleriana in the garden of Jill Fraumeni in Sydney

I particularly like using the white variety in shaded spots to illuminate the area. It looks good paired with white-variegated leaves, such as those of the polka-dot plant (Hypoestes phyllostachya), as illustrated at left. The other brilliant, jewel-like colours of Impatiens walleriana are also useful for creating such 'colour echoes' in shade using coleus as their foil - coleus have many different hues on their leaves that can be matched with a busy Lizzy bloom, such as pinks, reds and oranges.