In Sydney, we garden at a crossroads between temperate and subtropical climates. I think of it as the ‘cool subtropics’, and in more ways than one – we are famed as the ‘Emerald City’ after all. Our humid summers and very dry springs make our growing conditions quite different to the more mediterranean climates of southern Australia. Of course Sydney is a big, big city of around 1,700 square kilometres (650 sq miles) with any number of microclimates between the coastal suburbs and the foot of the Blue Mountains in the west, but its sticky, sweaty summers, scandalously short winters and late-summer peak rainfall are quite distinct.
That’s not to say we don’t have frosts and occasional below freezing temperatures, but in general what we can grow well in this coastal zone has more in common with the southern end of the subtropics than it does with the northern-most extremity of Australia’s cooler or dry summer Mediterranean climates. The problem is that most of us have learned our gardening styles from devouring beautiful English garden books, or those written by those talented gardening ‘Mexicans’ in Victoria. Believe me, I’ve had my share of lusting after cool climate beauties. Oh to grow a peony! Or a host of daffodils. Or a drop-dead gorgeous clematis – mine quickly lost the ‘gorgeous’ but was stand-out successful at the ‘drop-dead’.
Instead of thinking of these as restrictions, let’s embrace our ‘cool’ subtropical opportunities with these easy-to-grow plants from both the humid and dry subtropical regions of the world. NOTE that this is NOT the same as saying we should all have a subtropical garden style. I love them too, like Peter Nixon’s exquisite Sydney courtyard garden.
But the plants I’m recommending here will fit into any garden style – subtropical, cottage, formal – or just that eclectic mix we could call ‘Sydney suburban’. With minimal care, they won’t cark on you after heat, drought, light frost, torrential downpour, or day after day of high humidity. So whether you’re gardening in Bondi, Blacktown, Beecroft or Belrose, forget many of the salvias, the roses and the herbaceous perennials and go with the sub-troppo flow.
My best subtropical plants for a Sydney garden
Justicia brandegeeana – Shrimp plant from tropical Mexico has been around in Sydney gardens for decades but it’s surprisingly hard to find at a nursery. There are 2 common forms, one with rusty-red bracts and my favourite, Justicia brandegeeana ‘Lutea’, the yellow form. They tend to be somewhat lax shrubs (sounds a bit like me) so snip them now and then during spring and summer and then cut them down harder before their spring growth begins. They’ll flower away most of the year with very little interference on your part. There are other cultivars around like the one below in Helen Curran’s garden).
Murraya Min-a-min – If you’re sick of buxus (and especially the tom-cat smell of English box on a spring day – talk about eeuww), dwarf Murraya Min-a-min makes a small hedge or neat clipped mound. I love mine so much I need to pat its plump, dumpling shape every time I pass by. Full sun to semi shade, extremely drought tolerant and it’s not fussy about soil or drainage. It is slow growing but be patient, as once it’s at the size you want, a twice-yearly shear will keep it just right.
Megaskepasma erithroclamys – Brazilian Red Cloak is a giant shrub but easily controlled to a couple of metres each way if you prefer, and from autumn through to winter it rewards you with tall crimson-red bracts held above glossy green foliage. Prune it after flowering and strike more cuttings. There are many clumps of it through the Sydney Botanic Gardens and it’s often available from Growing Friends at the Botanic Gardens.
Strobilanthes dyerianus – Persian shield is another Acanthaceae plant. Usually sold as Strobilanthes dyerianus (although Deirdre Mowat of igarden questions that species name) it’s grown for its rich metallic purple foliage. Next to other plants with purple flowers, or alongside a contrasting yellow cordyline, it’s certainly got some zing. I cut mine down in late winter and then pinch out the new growth for several weeks through the spring to get it nice and bushy. Then I prune it back lightly a couple of times during the summer as I like mine compact.
Alectryon tomentosus – Hairy Alectryon (or just ‘Alec’ as it’s know in my family) is an everygreen tree native to the dry rainforests of northern NSW and Queensland that you can see growing along many roadsides in the Ku-ring-gai area of northern Sydney. Some clever arborist on council chose it as a street tree years ago, where it has performed extremely well, surviving prolonged drought, attack by passing truck and the regular butchering of electricity wire pruning. I had to get mine trucked down from a northern rivers nursery as I couldn’t find it for sale anywhere in Sydney. I believe it can self-seed in warmer climates but in the 4 years I’ve had mine it hasn’t, and I’ve never seen seedlings on the footpath under a mature specimen. New growth is downy and bronze-red, and the mature size in Sydney seems to be about 5 metres, although it’s easily pruned smaller. There are other species of Alectryon you might locate that look very similar – Alectryon coriaceus and Alectryon subcinereus.
Pentas lanceolata – Yeah, I know, here I go on about Pentas AGAIN, but it is the backbone of my garden from late spring through to early winter. The smaller varieties don’t over winter as well as the larger forms. Flower colours are white, through all the pinks to a vermilion red and also a lavender purple, and I’ve found pentas to be very drought hardy. Make yourself wait for the flowers and pinch prune off the top pair of leaves during its growth spurt in spring to get a nice bushy shrub. Regular deadheading keeps it more compact and also flowering for many months. Being part of the ‘grow fast, flower a lot and then die young’ club, a pentas plant won’t last more than 3-4 years, so you should strike some cuttings in late summer. Bunnings often sells this as cheap potted colour.
Epidendrum ibaguense – Crucifix orchids are epiphytic like most orchids but you can grow them in the ground in a very light, well-drained soil. I filled a small area behind a low retaining wall with a mix of equal parts by volume of pine bark fines, vermiculite and sand and they love it. I bought a collection of dwarf crucifix orchid cultivars from Coachwood Nursery at Somersby and there is ALWAYS one of them flowering at any time of year! It’s so lovely to open my front door and see their pretty heads of apricot, orange, white, pink and yellow. Plant them and leave them alone to slowly clump up.
Davidsonia pruriens – Davidson’s Plum hails from the Queensland rainforests but loves our Sydney climate. In a shady position it will grow into a narrow small tree with whorls of large, dark green leaves, or you can keep it cut to a tallish shrub like I do. Mine grows in underneath my Nyssa so it’s in complete shade in summer but enjoys the winter sunshine. Davidsonia is surprisingly drought tolerant and although mine doesn’t flower and fruit a lot, I have harvested some of the dark bluish ‘plums’ with which you can make a very tasty bushtucker jam.
Breynia disticha – Confetti bush (also called Breynia nivosa or with an additional cultivar name of ‘Roseopicta’) is one of those fabulous tri-coloured leaf plants that lightens up any garden. Hailing from Pacific Islands (various), it likes a humid climate but is still quite drought hardy. I grow mine as a background plant to my pink pentas and a lilly pilly hedge. Its long, graceful, arching branches with a distinctive zig-zag shape have pink, green and white leaves. In the depths of a very cold winter it loses some of its leaves and many take on a more bronzey hue, but through this mild winter it looks just as good as it did through the summer.
Mandevilla Sun Parasol White Fantasy – I bought this white-flowering Mandevilla vine for my daughter’s new garden in the Inner West and it has romped away, and never stopped flowering. The light green, deeply-veined leaves are also very attractive but those huge, white trumpet flowers with a yellow throat are divine. Unlike other climbers, it seems pretty happy to be a bit shrubby and hang about and flower where you can enjoy them, rather than racing away to dizzy heights. It’s growing in full summer sun but is part shaded during the winter without any ill effects.
Iresine herbstii – Bloodleaf plant’s leaves positively glow a vibrant crimson-red in the garden. It attracts attention wherever you put it and I have one either side of my front door to make a welcoming entrance. It’s very easy to grow from cuttings which will strike roots in just a glass of water. I cut mine back several times during the summer and pinch out new growth to keep it bushy, otherwise it will become leggy and flop over. There’s a pretty, multi-coloured red, green and cream leafed version which my friend Bernard Chapman charmingly refers to as ‘chicken gizzards’ that I find dies back during the winter but leafs up again quickly during spring.
Alcantarea species – OK, I have to confess I’m in two minds about these bromeliads. On the one hand, I see a luscious huge rosette of Alcantarea commanding attention in a Sydney garden and I think “double wow!” They look brilliant. And there’s no doubt these plants from the elevated subtropics of Brazil grow well here. But on the other hand, I bought a large and very expensive Alcantarea glaziouana which looked spectacular in a pot on my back deck. And then it promptly flowered. And you know what happens after a bromeliad rosette flowers? It dies. ‘Yes!’ its fans cry, ‘but it PUPS! And now you’ve got 15 Alcantareas where you only had one before!’ The trouble is I don’t want 15 small ones. I want the great big one with huge leaves that I started with. I know nothing is forever in the plant world, but really. I also grow quite a few small, colourful bromeliads and, although the same thing happens, it’s not really an issue as there’s no large hole left to fill. But with these big ones, I want to have at least a couple of years before I lose it!
So Sydneysiders, what other subtropical plants would you recommend?