On a truly horrible hot day like yesterday was in Sydney, we can be very thankful for those stalwarts of the summer garden that don't faint at the first sign of a 40° day. There are a number of compact shrubs which plough on regardless to continue to give us flowers in summer despite the heat. Many of the smaller Salvia shrubs, for example, seem to positively relish hot weather. Salvia microphylla, which comes from Arizona and Texas, and the ones which hail from South Africa (or are cultivars or hybrids of South African species) - such as Salvia scabra, Salvia 'African Sky' and Salvia muirii - are all very robust plants. The cultivar 'Wendy's Wish' has also coped with the heat well.
Another toughie is Pentas lanceolata, growing to around 1m in height, with flowers like neat round bouquets of tiny stars, in colours of red, white, lavender, purple, cerise and various shades of pink. They are at their best in sunny spots but flower reasonably well in 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. They are useful as cut flowers, and strike very readily from cuttings: one of my prettiest pink cultivars (pictured above) came to me as a part of a birthday posy many years ago.
Another very tough little shrub blooming all summer long is pink may (Spiraea japonica 'Anthony Waterer') from China and Japan - it may grow to 1.2 - 1.5m. A cousin of the well-known white may (Spiraea cantoniensis), it is deciduous, with narrow, toothed foliage. It bears clusters of tiny deep pink flowers. If the deadheads are removed after a flush of blooms, the shrub will re-flower several times in the warmer months. It needs no special care and seems to survive dry periods very well.
I have often mentioned the Acanthaceae family of plants as having many shrubby members very suited to our Sydney climate - they flower in various seasons, but summer sees the blooming of several examples. Asystasia salicifolia is an unusual small plant that I obtained at the local village fete many years ago and have never seen anywhere again. It has little bell-shaped flowers of plain white or lilac with a deep purple throat, and grows to 50 - 100cm tall. Like many others in the Acanthaceae family, it will tolerate shade and dry conditions. Belonging to the same family, Justicia brandegeeana, the shrimp plant, flowers almost all year round with its strange reddish-pink or greenish-yellow prawn-shaped flowers.
It is reassuring to think that though there will be inevitable fatalities of this searing summer, there are some resilient plants that will keep on blooming cheerfully despite the heat!
Tall summer volunteers
24 Jan 21
These will provide colour and form in your garden every summer.
A neon rainbow revisited
17 Jan 21
Hot-coloured flowers still feature in my summer garden
The zucchini files
10 Jan 21
Zucchini can be a rewarding summer crop.
Random musings on a walk
03 Jan 21
Lots of plants caught my eye on a walk.
13 Dec 20
Cut flowers for Christmas vases