Walking through London’s Kew Gardens on a winter’s day, the botanist Prof Tim Entwisle was struck by the sight of a Persian ironwood tree. The tree was leafless but not lifeless. While others in the gardens were bare-branched and stark, the ironwood’s vibrant red blossoms stood out against the snow.
The image stayed with Entwisle. It prompted him to plant a Persian ironwood (Parrotia persica) at his home in Melbourne, where it thrives, out of place, in the heart of an orderly garden.
“It’s an interesting, intriguing tree,” he says. “It doesn’t fit, but growing it reminds me of that time at Kew.”
As the director and chief executive of the Royal Botanic Gardens Victoria, Entwisle is surrounded by well-planned plantings, specimen trees and 170 years of development. Botanic gardens select their plants according to strict collection policies. Species might be chosen for their place of origin, rarity, cultural or economic importance, or because they belong to a specific group. Every acquisition is backed by a documented reason.
But home gardens are different. They are places of relaxation and self-care, a source of food and flowers, and a shield from the noise and chaos of the city. They range from courtyards and cottage gardens to lush backyards barely restrained with secateurs.
So what do professional botanists grow in their gardens?
In far north Queensland, Stuart Worboys climbs mountains to save rare plants. On those highest peaks, climate change is herding species closer to the edge, so Worboys and his colleagues at the Australian Tropical Herbarium in Cairns gather seeds to grow in botanic gardens. Some are stored for the future, while others are planted in living collections.
Among the mountaintop species are the exquisite native rhododendrons (Rhododendron lochiae and R viriosum), which have been in cultivation for many years. A more recent introduction to home gardens is Wilkie’s leatherwood (Eucryphia wilkiei). Its natural habitat is the windswept granite boulders on top of Queensland’s tallest mountain, Chooreechillum/Mount Bartle Frere.
“Eucryphia grows beautifully in gardens, but I can’t grow it in Cairns because it would melt,” Worboys says.
Instead, he grows more rugged species.
On moving to a new house, his first change was to thin out the clumping palms that crowded the front garden. He replaced them with a golden bouquet tree (Deplanchea tetraphylla), native to north-east Queensland and New Guinea. When it blossoms, the tree fills with lorikeets and honeyeaters.
He also planted banksias, the red-flowered form of broad-leaved paperbark (Melaleuca viridiflora), and Senna magnifolia, a tropical dry-country species that carries incandescent yellow flowers for nine months of the year. What connects these plants are their sculptural forms – “gloriously gnarly,” Worboys says – and their appeal to birds and insects.
In Sydney, Dr Cathy Offord, the principal research scientist and manager of the Australian PlantBank at the Australian Botanic Garden Mount Annan, also works with endangered species, including those collected by Worboys in far north Queensland. She is involved in conserving the Wollemi pine (Wollemia nobilis) and macadamia (Macadamia tetraphylla), which is vulnerable to extinction in the wild.
In Offord’s own garden, “I like to mix it up,” she says.
Alongside a dragon fruit (Selenicereus) scrambling up a tibouchina (Tibouchina), there are orchids, succulents and a bonsai collection that includes a native rhododendron – “the species really lends itself to bonsai” – and a Wollemi pine.
Vertical surfaces provide opportunities for high-rise plantings. A hardwood fence, built to hide a shed, is covered in bromeliads.
“One of my secret passions,” she says. “Not everyone loves them, but I do.”
Dr Dale Dixon also loves bromeliads. Since retiring from his position as curator manager at the Royal Botanic Garden Sydney, he has had more time to devote to his collection of tillandsias, a group of bromeliads also known as air plants.
“I was given my first tillandsia when I was 13 or 14,” he says. “It was Tillandsia usneoides – Spanish moss – but I didn’t know what it was at the time. While studying botany at university, I started to collect them.”
Dixon has about 360 species. He follows a policy to ensure his collection develops in the right direction. Wherever possible, plants are accompanied with data about their place of origin and collector. Not all of the species have been described and given a scientific name, and provenance is vitally important to that process.
Dixon’s garden is filled with palms and cycads for a tropical feel, and he selects other plants for their flowers and shape “to add different texture”.
As senior curator at the Botanic Gardens of South Australia’s nursery, Matt Coulter works with a wide variety of species. But he is especially interested in the titan arum (Amorphophallus titanum). When a titan arum blooms, it makes the news. This rare species from the rainforests of Sumatra produces a three-metre flower spike wrapped in a dark purple collar. It also stinks of rotting meat to bring in its pollinators – blowflies and carrion beetles.
Coulter has spent 14 years working on the cultivation of the titan arum and related species. He exchanges information with other experts around the world.
“I’m lucky to have all these interesting plants at work,” he says.
But at home, Coulter’s passion is growing fruit and vegetables. His small garden is packed with heirloom crops and rare varieties. To maximise space, he grows his fruit trees as espaliers, pruned and tied to frames.
“I love plants and I love cooking, and I can bring those two things together at home. If I have any free time, I’m in the garden.”