Strobilanthes dyeriana, right, with Plectranthus argentatus

Around this time of year, certain plants that have been waiting patiently for warmer weather to kick in, start to strut their stuff and become an important presence in my garden. The Sydney climate is such that our mild winter enables many semitropical plants to survive, even though they may look quite woebegone for a while. Luckily, we can be distracted by the many lovely spring-blooming specimens that do well in our region. Once these are over, the semitropical ones can take centre stage and provide interest and colour throughout summer and well into autumn, thus having great value in the garden.

Coleus provide brilliantly coloured foliage

Coleus provide brilliantly coloured foliage

Many of these plants are grown for their beautiful foliage. Coleus (Solenostemon hybrids and cultivars) have myriad colours and patterns on their soft leaves, some of which have frilled edges, and they can get up to a metre high during summer. There are so many to choose from but some of my own favourites include one with brilliant yellow leaves with a dark burgundy centre and veining; a dark green version with an alluring dark edge; one with orange and yellow markings; and single-hued forms of burgundy and lime. They are ideal for shaded spots and offer many opportunities for creating colour echoes with the leaves or flowers of other plants. They look very sad in winter but - like most of the shrubby plants mentioned in this blog - should not be cut back until around early September, as late cold snaps can kill them. I often take cuttings of my best ones in autumn, just in case they succumb to winter cold. Their blooms are insignificant, and it's best to remove the flower stalk when it appears.

Iresine herbstii Brilliantissima

Iresine herbstii Brilliantissima

Other attractive warm-climate foliage plants include Iresine herbstii, which has cultivars in brilliant cerise, yellow-and-green stripes, and deep purplish-brown. All do well in shade but can be grown in sun as well. Alternanthera dentata is another plant with purplish-brown leaves that starts to fill out in late October and can become a large mound by the time summer comes around. Its cultivar 'Little Ruby' is a good compact form. Alternanthera does best in sun.

Xanthosoma Lime Zinger with Colocasia Black Magic

Xanthosoma Lime Zinger with Colocasia Black Magic

Colocasia esculenta (elephant's ears) are plants that also look pretty miserable in winter, and may even die back completely, but they reappear in spring and sport their large velvety arrowhead-shaped leaves once more, sumptuous deep purplish-black in the cultivar 'Black Magic'. A related plant is Xanthosoma 'Lime Zinger', which has similarly shaped leaves that are a glowing lime green. The foliage looks superb all summer long. These plants are best suited to shade, and grow well in pots.

Modern form of Hypoestes phyllostachia

Modern form of Hypoestes phyllostachia

Members of the Acanthaceae family of plants come mainly from warm-climate parts of the world, so they may look a bit wretched in winter but come good once summer is within sight. Some excellent foliage plants from the family include Strobilanthes dyeriana, with its large, shiny silver and green leaves overlaid with a lustrous purple sheen, vivid veining, and an attractive texture (pictured at the start of the blog). Its flowers are nondescript, as are those of another family member, usually called the polka-dot or freckle-face plant (Hypoestes phyllostachya). The original species had green leaves with small white or pink dots, but recently bred versions have larger splashes of colour, and last week I bought pink-, white- and red-variegated plants that have quite an impact.

Dark pink form of Justicia carnea

Dark pink form of Justicia carnea

The Acanthaceae family also has flowering plants that are gearing up for the warmer weather: Justicia carnea is already bearing its tousled plumes of pink or white; Ruellia elegans has its red or bright pink funnel-shaped flowers from now until autumn Justicia betonica will soon be covered in spires of white-bracted flowers that will remain attractive for months; and Odontonema tubaeforme will display its blood-red blooms in late summer.

Dahlias from the garden of Sandra Wilson in Sydney

Dahlias from the garden of Sandra Wilson in Sydney

Dahlia have filled out rapidly over the last few weeks and are beginning to show their pretty daisy-like blooms in many hues. Their tubers lie dormant all winter and sprout only once warmer weather kicks in. They will flower for months, until the end of autumn, if deadheaded regularly and given regular feeds of liquid fertiliser. Canna also are quiescent during winter and push up their bold, paddle-shaped leaves once spring arrives, followed soon after by a long succession of blooms in in brilliant colours ranging from soft cream through pinks to deep red. Some cultivars, such as 'Striata' and 'Tropicanna' have highly decorative striped leaves and are worth growing for those alone.

Growing some of these plants in your Sydney garden will ensure colour and interest for many months ahead. Note that in colder suburbs, many of these plants will need shelter over winter, or should be grown anew each year from cuttings.