Plants from the genus Wahlenbergia (family Campanulaceae [bellflower] family) are found throughout the temperate Southern Hemisphere. Australia has around 25 species of Wahlenbergia out of a total of some 200.
The genus includes annuals and perennials both evergreen and deciduous. The flowers are generally some shade of blue and are borne on the ends of branched stems. The leaves may be notched or smooth-edged.
Wahlenbergia communis (also called W.bicolour) has the common names of Australian bluebell, grass-leaf bluebell or tufted bluebell). As the name suggests, it is tufted and a deciduous perennial found throughout the continent. The leaves are slender and may reach 8cm in length. They can sometimes be toothed. The pale blue flowers are star-shaped with thin stems. The flowering season is spring to summer.
Also known as the Australian bluebell is Wahlenbergia gloriosa. It is also known as alpine bluebell or royal bluebell and comes from the alpine areas of New South Wales, the Australian Capital Territory (ACT) and Victoria. It has been chosen as the flower emblem of the ACT. It is a prostrate deciduous perennial which spreads to about 1 metre. It has dark green leaves of a rather broad lance shape and 2 to 3cm long. The edges may be wavy or toothed. The bell-shaped flowers are dark blue to purple and appear in summer on slender stems. It likes a sunny but moist position and will spread by suckering.
Wahlenbergia stricta is also known as W.consimilis, native bluebell and tall bluebell. It grows to 60cm tall and has pale blue flowers up to 25mm wide. The flowering season is from spring to summer. At the base of the plant the leaves are oval and hairy but higher up the stems they become linear in shape and smooth in texture.
Westringia kydrensis (Kydra westringia) occurs south-east of Cooma, New South Wales, specifically on rocky areas at Kydra Reefs. It is regarded as endangered. Kydra westringia grows to about 40cm tall and is an erect shrub with groups of three leaves arranged in whorls round the stems. The leaves are hairy when young reaching about 8mm long by 3.5mm wide at maturity. The flowers are white with sparse reddish spots at the lobe bases.
Wahlenbergias are generally easy to grow. They will grow in most soils, although species native to mountainous areas prefer a peaty acid soil. They like full sun. The creeping varieties are ideal for rock gardens. Because of the small size of the flowers, those with an erect habit will make a more conspicuous display if planted en masse in garden beds. An additional bonus for those gardeners growing Wahlenbergias is that the plants will attract butterflies to the garden.