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

Last week, in the garden of a friend on the Central Coast of NSW, another friend and I spied a colourful display of 'busy Lizzie' (Impatiens walleriana, ht 30-60 cm) plants in full bloom. She told us she had bought them from her local nursery in a punnet a few weeks ago. It's more than 11 years since I wrote a blog entitled 'The disappearance of Lizzie', bemoaning that one of my favourite annual plants for shade had 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 were no longer available in nurseries and the future for them looked grim.

White Impatiens walleriana in the garden of Jill Fraumeni in Sydney

White Impatiens walleriana in the garden of Jill Fraumeni in Sydney

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 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. Indeed, when my friends and I visited the local nursery last week, I was able to buy a punnet with busy Lizzies in colours I had never had before in my garden! It is said that these new-generation plants still have a lengthy flowering season and need little care.

Double form of Impatiens walleriana

Double form of Impatiens walleriana

It will be interesting to see how these seedlings perform (especially if we have any periods of humid, damp weather) and whether they self-seed like the old busy Lizzies did - I used to encourage this in shaded areas of my garden! There are cute double forms, like little roses, that don't self-seed. Compact forms grow well in pots. I particularly liked using the white variety in shaded spots to illuminate the area and I have just now popped in a couple of them in a long, shaded border where I grow ferns, Begonia, Hydrangea, Plectranthus and other plants that can tolerate low light levels. They do best in soil amended with organic matter, and sufficient water.

The brilliant, jewel-like colours of Impatiens walleriana are so useful for creating 'colour echoes' in shade using various coleus types as their foil - coleus have many different hues on their leaves that can be matched with a busy Lizzy bloom. The white form looks good paired with white-variegated leaves, such as those of the polka-dot plant (Hypoestes phyllostachya), as shown earlier in the blog.

New Guinea Impatiens hybrid in the garden of Kathryn Hipkin in Sydney

New Guinea Impatiens hybrid in the garden of Kathryn Hipkin in Sydney

Other species and cultivars of Impatiens were never affected by the pathogen. The New Guinea Impatiens (Impatiens hawkeri and its hybrids) are very attractive plants, with larger flowers in a range of lovely colours. Some also have interesting dark-coloured or variegated leaves. They do reasonably well in shade but they don't self-seed, and eventually need to be replaced by cuttings when they get tired - but they should last a few seasons, except in very cold suburbs.

Impatiens bicaudata

Impatiens bicaudata

I used to grow quite a tall, shrubby species, called Impatiens sodenii (ht 1-3 m), which had soft pastel lilac flowers. Impatiens bicaudata (ht 1.8 m) is another shrubby species with curled orange flowers almost all year round. Impatiens niamniamensis 'Congo Cockatoo' (ht 1 m) has very unusual curved red and yellow blooms.

In any case, let's hope Lizzie is back to join her resilient relatives and will be with us for a long time to come!