Pentas lanceolata is an excellent small shrub for Sydney gardens, and belongs to the Rubiaceae family of plants. It grows to around 1 m in height, with summer and autumn flowers like neat round bouquets of tiny stars, in colours of red, white, lavender, purple, cerise and various shades of pink. Some have flowers with a white stripes on the petals, and there is a cultivar known as 'Touch of Ice' that has interesting variegated leaves - it is not as robust as most of the others. I don't know the proper cultivar names of any other sorts that I grow - I usually refer to them by the name of the person who gave them to me! There are dwarf strains that have become available in recent times, which only seem to grow to 30cm or so - I am not so keen on these as they don't really make much impact in the garden and don't seem to survive more than one season. They are probably best suited to pot culture.
Pentas shrubs are at their best in sunny spots but flower reasonably well in part-shade - the red variety is particularly reliable in this regard and is useful for providing a glow of colour in gloomy spots. They mix in very well with other warm-climate summer perennials and shrubs, such as Salvia, Dahlia and Canna.
Pentas needs just ordinary, well-drained soil and occasional watering - it seems to stand up to the summer onslaught of heat very well. The plants do look a bit sad in winter: denizens of tropical Africa, Madagascar and the Arabian Peninsula, they don't enjoy the colder months but they will generally survive an average Sydney winter, as long as they are not pruned until the warmer weather returns in September. In areas of Sydney with very cold winters, they may not survive: it is a good idea to take cuttings in autumn and plant these out in spring. I do trim them very lightly from time to time during their flowering season to promote extra blooms. They are useful as cut flowers, and strike reasonably readily from cuttings taken in spring or autumn: one of my prettiest pink cultivars (pictured above) came to me as a part of a birthday posy many years ago. From this, I learnt is that it seems to help to put the cutting in water for a week or so before it is potted up. It is a good idea to replace old, woody specimens with a freshly propagated plant every few years, as they do lose vitality eventually.