Pentas lanceolata

Though it is officially autumn (according to some calendars, anyway), we can still expect some hot days this month. On such days, I find myself drawn to white flowers - just as someone wearing a white linen dress immediately gives the look of coolness. Some of these plants in my garden have been catching my eye over this past torrid week. A tall Pentas (ht 1 m) with clustered heads of pure white starry blooms is unfazed by the heat, and will plough on till May. These worthwhile shrubs are stalwarts of my summer garden, and I have various colours of them - the icy white one is a favourite, however. These taller versions are not really sold in nurseries these days, where only the very low-growing ones that are really just annuals are stocked. These larger beauties have to be grown from cuttings begged from friends fortunate to have them growing in their gardens! Pentas do best in sun but will tolerate part shade.

Mussaenda frondosa sepal

Mussaenda frondosa sepal

From the same Rubiaceae plant family as the Pentas, Mussaenda frondosa (ht 2 m) is an unusual shrub from India, with small, orange, star-shaped flowers in summer accompanied by large, white individual sepals that look like leaves. The sepals last well into autumn. One common name for the plant is the white flag bush, and the sepals do look as if bunting has been draped amongst the branches. They look effective grown near dainty, white flowered plants like their relative the Pentas, or underplanted with a large form of white-spathed Spathiphyllum to echo the form of its sepals. Mussaenda frondosa will grow in sun or part-shade - a site protected by trees will provide frost protection in winter.

Begonia undulata

Begonia undulata

The shrubby Chinese lantern plant (Abutilon hybrids (ht 1-2 m) comes back into bloom this month, and there are various white-flowered forms. They are best in a part-shaded spot with morning sun. Cane-stemmed Begonia have been in flower for months but I always think they are at their peak around now. One of most commonly seen is Begonia undulata (ht to 2 m) and it simply drips with trusses of waxy, white flowers. It is perfect for a shaded border and asks for very little from the gardener!

Perennial Cleome Senorita Luna

Perennial Cleome Senorita Luna

Amongst perennials, refreshing white blooms are offered by Euphorbia 'Diamond Frost' (ht 50 cm), which is basically always in flower, offering a smattering of tiny inflorescences that soften any planting scheme. The low-growing forms of Alstroemeria (ht to 30 cm) have white varieties, which bloom for many months. The so-called perennial Cleome hybrid (ht 1 m) has a crisp white cultivar - though the plants often exhaust themselves after a year or so. The spidery blooms provide an interesting contrast to other floral shapes.

Catharanthus rosea

Catharanthus rosea

Annual flowers also come in whites: such as busy Lizzie Impatiens walleriana (ht 30-60 cm), which have returned to our shady gardens in recent times; Catharanthus rosea (ht to 60 cm), sometimes known as vinca, has rounded white flowers rather similar to those of the Impatiens but it prefers to grow in a sunny place; Calibrachoa, or trailing petunia (ht 15-30 cm), is also a sun-lover, with a profusion of bell-shaped flowers, seeming to do best in a pot. The white form of annual Salvia coccinea (ht 50-80 cm) self-seeds in my garden, adding its dainty spires here and there. The white star-like flowers of Zepyranthes candida (ht 15-25 cm) appear around this time, after rain, adding a fresh note to the garden.

I think that white flowers surrounded by lush green foliage are one of the most cooling sights in the garden. I also like the flowers grown nearby white-variegated leaves, to provide a 'colour echo'. White flowers also look delightful when nestled in with silver foliage. Let's hope this hot, humid spell will soon be over, and we can then look forward to the very best time of year in the Sydney garden: autumn!