GARDENS ON THE MOVE

Global Warming is having a similar effect as putting my Brisbane garden on a trailer and slowly dragging it to Townsville.

I planted my Brisbane garden in 2004 with plants I expected would grow successfully into our emerging new climate: palms, cycads, pandanus, ferns, bromeliads, succulents, bulbs and other perennials. I planted a few for food and medicine, others for fragrance and ornamental foliage.

I anticipated conditions predicted for Brisbane 2030: hotter, more humid, reduced cloud cover, heavier and more widely separated falls of rain, reduced winter chill – and seriously dodgy hail storms. I was guided by the report ‘Climate Change: An Australian Guide to the Science and Potential Impacts’, published by the Australian Greenhouse Office, in December 2003*.

In November 2004, I planted 150 different kinds of plant to start a Climate Change Ready garden.

Planting native trees in Brisbane? My Queensland bottle tree is a dry rainforest species, and this plant community includes many pretty and tough species. Capable of withstanding greater climate stresses than wet rainforest species, I regard them as climate change ‘winners’. Kumbartcho Sanctuary and Nursery is a good source of dry rainforest species not found in commerce.

If you want to grow a native tree, consider its natural distribution. The Atlas of Living Australia is a useful reference. If your chosen species has a natural distribution that extends north of Brisbane, gather seed or buy stock originating from its northernmost location. Those northern plants will already be better adapted to a more extreme climate and their seed will be primed and ready for the stresses and strains of Brisbane’s emerging new climate.

For example, Pandanus cookii is a tropical tree which occurs from Mackay northwards. I sourced a seedling from Cairns in far northern Queensland in 1995. It turned out to be a female and she is very at home here. Planted before a succession of record breaking hot Brisbane summers, she’s looking great. Instead of carrying fruit in autumn, she now carries fruit all year round.

Horticulture has no option but to keep up with climate change and even certain Australian botanic gardens have realised they can no longer ignore the need to adapt their collections as I did here in Brisbane in 2004.

In 2019, ABC News published a good illustrative guide showing how global warming has already and will continue impacting horticulture, food production and the general liveability of Australia.

“We estimate that the shift in climate has cut average annual broadacre farm profits by around 22%, which is an average of $18,600 per farm per year, controlling for all other factors.

The effects have been most pronounced in the cropping sector, reducing average profits by 35%, or $70,900 a year for a typical cropping farm.

At a national level this amounts to an average loss in production of broadacre crops of around $1.1 billion a year,” Australian Bureau of Agricultural and Resource Economics and Sciences, December 2019.

Some of the plants illustrated below were removed because even with just natural rainfall during the Millennium Drought they grew too big, too fast. Others did too well during the floods in 2011, 2012 and 2013.

The Jubaea chilensis, the Chilean wine palm, was purchased as a tubestock seedling in 1995 and planted here in 2004. Since 2009, it started flowering and it has never stopped growing, flowering or producing miniature coconuts. In Sydney, this palm fruits each autumn. Here in Brisbane it requires a flood year to fruit. Fruit taste something between a sweet apricot and a slightly under-ripe peach; quite delicious if de-seeded and cooked with pandan leaves and sugar before bottling.

As of January 2020 there remain 135 different kinds of plant.

Clicking on each image opens the notes.

Euphorbia tithymaloides subsp. tirucallii var. smallii ‘Harlequin’. Copes with winter drought drought and hot, humid summers.

Female Pandanus cookii. Queensland endemic, native from Mackay northwards. Highly successful.

Euphorbia graminea. Nectar attracts zebra butterflies.

Euphorbia geroldii, a critically endangered succulent from dry tropical rainforest in Madagascar. Needs dappled shade.

Bulbine frutescens, burn jelly plant. Sap used like Aloe vera. Attracts stingless bees.

Plumeria filifolia. Resistant to frangipani rust and only stops flowering in July and August. Produces viable seed.

Acalypha reptans ‘Summer Love’. Dies back during drought.

Rough adiantum, Adiantum hispidulum. Dies back during drought.

Aechmea gamosepala ‘Variegata’. Needs a splash of water during drought.

Agave mexicana ‘Variegata’. Suckering perennial succulent with fierce spines. Removed because it grew too fast even during drought.

Allamanda cathartica, a slightly weedy Venezuelan vine. With vigilance it’s manageable and flowers throughout the warm season.

Planted with a soft-spined cultivar of Aloe vera in 2007. The Aloe vera border has been highly popular with passersby who regularly help themselves to cuttings. Highly popular.

Ananas bracteatus ‘Variegatus’. Sold as an ornamental, but the fruit taste good. Needs some watering in drought.

Ananas comosus ‘Queensland Rough’ pineapple. Prickly plants produce sweet, aromatic, flavoursome fruit with cores soft enough to eat. Needs some watering.

Ananas comosus Accession No: 34-76 from Maroochy Research Station in 2003. Needs some watering in drought.

Dwarf pineapple, Ananas nanus. A vicious little perennial prefers semi-shade. Produces autumn fruit that are just about edible.

Aneilema acuminata is a well-behaved native rainforest plant and relative of weedy wandering jew. Dies back during drought.

Aspidistra elatior grows well in semi-shade under the east-facing front steps. Flowers are slug-pollinated.

Aspidistra elatior may be called the Cast Iron plant, but it needs an occasional splash to look lush in drought.

Bambusa sp. Murray Island. This native was removed because it grew too well and made too much mess, even during drought. A potential fire hazard which filled gutters with dead leaves.

Banksia aemula, Wallum Banksia, beloved by bees, but sensitive to ongoing drought. In the wild, plants tap into the water table.

Billbergia nutans flowers in mid-winter. Needs bright light, but direct sunshine burns the foliage.

Brachychiton bidwillii, Little Kurrajong. Cut annually to the ground after flowering is finished to encourage vigorous, decorative foliage. May be trained into a small tree. Very successful.

Brachychiton rupestris, Queensland bottle tree. A seed grown specimen pictured a year after planting. Flowers annually. Very successful.

Brachychiton rupestris, Queensland Bottle tree at five years old. In good years, produces two flushes of extension growth.

Calliandra haematocephala, prostrate form. Also does well in Brisbane kerbside plantings.

Natal Plum, Carissa macrocarpa. Makes an impenetrable, prickly hedge or shrub with edible fruit ideal for jams. Removed because it grew so fast during drought.

Canistrum aurantiacum. Grows large and I restrict growth by keeping it in a pot.

Crinum x powellii ‘Alba’ requires protection from midday and afternoon sunshine. Spray with neem oil to prevent amaryllis caterpillar attack.

Dioon spinulosum. Purchased 1995, planted 2004. A spectacular alternative to Cycas revoluta which is attacked by cycad blue butterfly.

Encephalartos ferox. Leaves may be burned in ongoing drought.

Plumeria rubra ‘Irma Bryan’ syn ‘Blood Red’. Susceptible to frangipani rust, but otherwise successful.

Tillandsia usneoides. Needs an occasional splash of water when summer humidity drops.

Euphorbia splendens ‘Fireworks’.

Neoregelia x ‘Fireball’. Foliage exposed to midday sunshine burns in heatwaves.

Hyophorbe lagenicaulis, bottle palm. Excellent and attracts native Homalictus bees which help it set seed.

Hyophorbe verschaffeltii, spindle palm. Excellent, flowers are fragrant and produced all year round.

Salvia discolor from Chile. Hasn’t stopped flowering since being planted in Sept 2004.

Portea petropolitana. Very successful.

Macrozamia spiralis. Very successful and will drop leaves to survive extreme drought.

Kalanchoe orgyalis. Flowers attract birds. Very successful.

Dianella caerulea ‘Variegata’. Requires an occasional splash of water to keep looking fresh during ongoing drought.

Alpinia zerumbet ‘Variegata’. Variegated shell ginger is very successful. If they look shabby in drought, cut them down and let them resprout after rain.

Encephalartos altensteinii thrives even in drought. Very successful.

x Cryptbergia ‘Red Burst’ tolerates light frost, extreme heat and drought, but does best given bright light, not all day sunshine.

Plumeria obtusa var. sericifolia is resistant to frangipani rust. Very successful.

Zamia furfuracea, aka cardboard fern, is one of the most successful cycads for a warm, dry, sunny position.

* The Australian Greenhouse Office was initially independent of government interference, but subsequent reshuffling brought it under direct control and its functions have now been diluted by other government departments.