There are two different sorts of plants that I grow that are colloquially called 'butterfly bushes', and both are blooming now. The first one gets its name from the shape of its flowers, which really do resemble beautiful blue butterflies. This is Clerodendrum ugandense, a warm-climate plant which hails from tropical East Africa. It grows to about 2-3m tall and flowers in late summer and autumn. The charming flowers are not large so it is best to appreciate them at close quarters: they have several tones of blue on the 'wings' and the stamens look like the antennae of butterflies. It grows best in sun (though will cope with part-shade), in reasonably fertile soil with adequate moisture. Like many warm-climate shrubs, it may look a bit untidy through winter, but it is best not to prune it until around the end of August. It mixes easily into any colour scheme, but I am currently enjoying it with the pale lemon trumpets of the so-called 'Cape Fuchsia', Phygelius x rectus 'Moonraker'.
There are other plants in the Clerodendrum genus that do well in our gardens, given a position sheltered from winter cold. These include Clerodendrum wallichii (syn. C. nutans), ht 2m, which has stunning pendulous white flowers in autumn, and the pretty climbers C. x speciosum , which has pinkish-red blooms in summer and autumn and C. splendens, which has bright red flowers in mid-autumn and winter. Some, however, are to be avoided, including C. bungei, a shrubby form that suckers terribly. Others need a warmer climate than ours to thrive properly.
The second of my 'butterfly bushes' gets its name because it attracts butterflies: this is the genus Buddleja davidii, of Chinese and Japanese origin, which does as well in Sydney gardens as it does in much cooler areas. In late spring and throughout summer, its arching branches bear long, tapering panicles are made up of dense clusters of tiny, fragrant flowers, in colours of white, mauve, deep purple, magenta and pink. They are generally medium to tall shrubs growing to 2-3.5m; however, there are also dwarf cultivars, such as 'White Ball', for smaller spaces. My favourite of the taller cultivars is 'Pink Delight', with mid-pink blooms. There are a couple of interesting variegated-leaf cultivars, such as 'Harlequin', which has cream-margined foliage and deep red-purple blooms. Butterflies feast on the scented nectar of the blooms, and when 'blue triangle' butterflies, with their stunning turquoise-coloured wings are hovering around the flowers, it is an amazing sight!
Buddleja 'Lochinch (ht 2.5m) is a lovely hybrid and has handsome silvery leaves and highly scented lilac flowers. The first flush of blooms occurs around November, and if the plant is dead-headed, further flowerings will occur through summer. I also have a Buddleja (which I think is B. farreri) with large, broad silvery leaves, quite unlike the usual long, narrow leaves of the genus. It rarely flowers but is worth growing as a foliage plant. B. 'Silver Anniversary' (also known as 'Morning Mist'), ht 1.5cm, is a new hybrid with lovely felted silver foliage and rounded trusses of white flowers. The flowers are not very interesting and tend to go brown quickly so I often cut them off and simply appreciate the lovely leaves. I enjoy growing this in a border devoted to silvery leaved plants contrasted with very dark purple/black foliage plants and white-variegated ones.
Buddleja flower best in a sunny, well-drained spot. They are quite tough once established, and survive dry spells very well. I cut mine back very hard around mid-August, reducing each one almost to a stump! New growth will soon emerge and a nice shape will form. Left unpruned, they can become very straggly. They make a good statement in any mixed border, with companions such as Salvia, Abutilon, perennial Aster, Dahlia and Canna.
Cuttings of both Buddleja and Clerondendrum strike fairly easily and late summer and autumn are good times to try them. Note that Buddleja may self-seed, so make sure they are not planted nearby bush reserves and that you pull out all unwanted seedlings in your garden, so that you don't end up with a forest of Buddleja!
18 Oct 20
Although my garden is semi-tropical in nature now, I still have some vestiges from my cottage garden days!
11 Oct 20
Consider training a shrub into a small tree.
04 Oct 20
October is iris time in Sydney gardens: the best are the tall bearded irises and Louisiana irises.
One crowded hour
27 Sep 20
Much can be achieved in regular short stints in the garden.
20 Sep 20
We may not be able to grow massed displays of tulips in our climate, but try some of these South African corms instead.