Can the iconic boab be grown in your own backyard?

This striking tree could be the perfect solution for those of us searching for a unique feature in our gardens.

Boab trees can grow up to 12m tall with trunks that swell massively during the wet as their spongy tissue absorbs water.

Bottle tree or boab? There’s lots of confusion as both common names refer to trees with trunks that swell to a bottle shape to store water. Australia has two, unrelated, species. The Queensland bottle tree, Brachychiton rupestris (pictured), is well known as it’s adaptable enough to grow all over Australia. While it can reach 20m in the wild, in cultivation it’s usually less than 10m, with a succulent taproot and fine fibrous roots that don’t spread far, making it a suitable specimen tree for smaller spaces. The glossy green, narrow leaves change in shape as the tree matures and it’s mostly evergreen. The boab trees that are iconic in the Kimberley region are Adansonia gregorii. This is the sole Australian species; there are six from Madagascar and one from Africa. Genetics of our species suggest seeds drifted from Madagascar millions of years ago and evolved here into a new species. First Nations people are thought to have gradually spread it inland but it struggles to survive outside its northwest habitat. The trees can grow up to 12m tall with trunks that swell massively during the wet as their spongy tissue absorbs water. In the dry, boabs lose their palmate-shaped leaves and are dormant. For more: Australian Bottle Trees and Boabs by Attila Kapitany.

Camellia Season

Camellia japonicais a winter flowering shrub with glossy dark green leaves, ideal for semi-shaded spots.

Camellia 'Hawaii'.

Camellia japonica 'Roger Hall'

Mature plants produce hundreds of blooms, yet are low maintenance. There are hundreds of varieties, ranging from white to red and every shade of pink.

Camellia japonica ‘Desire’

Camellia japonica ‘Silver Waves’

Q&A

Tomato plants have started to appear all over our vegie boxes after a bumper season. Will they grow over winter?

Leigh Stacey, southwest Victoria

Self-seeded plants are often the strongest so it’s worth a shot. Tomato seedlings won’t survive frosts, so if you get frosts you’ll need to pot up the seedlings and overwinter them in a greenhouse, warm courtyard or a sunny spot indoors. Give them Seasol fortnightly to strengthen them. If you can nurture them through winter, the traditional time for planting tomato seedlings in the garden in Victoria is the first week of November, when the soil has warmed up. In coastal Queensland, winter is the preferred growing season.

The loose pebbles around my pool coping are a nightmare for weeds. There was weedmat underneath but organic matter has built up so the weeds flourish in it. Any solutions?

Dave Hayes, by email

Organic weedkillers such as Slasher should kill small, self-seeded weeds, or pour boiling water on them, but this will be a constant job. You could lift and wash the pebbles, then re-lay them on top of new weedmat. You can also pour over a clear or amber resin to bind and stabilise clean pebbles or gravel (of 6-20mm diameter) through companies such as Stone Set.

What largish plants will survive in planter boxes without a lot of water or TLC on a west-facing, sometimes windy, second-floor balcony?

Jan Kendall, Melbourne

Some plants to consider include oleanders in various colours, silverberry (Elaeagnus x ebbingei), olives, spineless yucca (Yucca elephantipes) and New Zealand Christmas bush (Metrosideros). All plants will grow better with care, such as regular water, fertiliser, good quality soil mix and mulch.

Send your questions to [e-mail] The best question for July wins a bundle of three stylish Le Sac gardening belts, valued at $228, to keep your tools, phone, and accessories at hand while gardening. June’s winner is Anne Ruwald of Murrumbateman for her question about Confidor.

Le Sac gardening belt.