How to pick the right rare flowers for your garden

The colour blue is associated with calm, cool, peaceful spaces, but show me a blue flower and I’m anything but calm. The thrill of blue comes from its rarity as a flower colour. Most of the flowers we call blue are actually purple or lavender. (Exhibit A: the misnamed “Blue Moon” rose, which is actually the tint that older ladies once used to dye their hair.)

The bluest of truly blue flowers is the Himalayan blue poppy, Mecanopsis betonicifolia, which is the colour of blue ink painted on tissue paper. It’s one of those wildly desirable flowers that lure gardeners in completely inappropriate climates to kill them in the attempt to grow them. The likely failure is right there in the name. The best patches I’ve seen are in the Edinburgh Botanic Gardens in Scotland and at Bodnant Garden in Wales: more proof that they thrive in cool, damp summers.

Also inky blue and mountain-dwelling is Puya alpestris, a bromeliad from the Chilean Andes. Its common name is sapphire tower, and the inflorescence is a pyramidal spire of teal-blue flowers up to 3m high. Though heart-stoppingly dramatic, and more climate-tolerant than the blue poppy, this is not a domestic garden subject either, as the spiky leaves of the rosette can be a metre long, requiring plenty of space. See it in botanic gardens – there’s a clump at Blue Mountains Botanic Garden at Mount Tomah, one at the Adelaide Botanic Garden and another in Melbourne’s Botanic Garden.

Our own true blue is Lechenaultia biloba, with brilliant mid-blue flowers in late winter. It’s native to south-west Western Australia, where it springs up in profusion following fires. It doesn’t like gardens much, nor east Australian weather, but it can be enjoyed in a pot or hanging basket while it’s flowering, and not mourned too severely when it rots away in summer.

In the sky-blue range, forget-me-not and plumbago are easy to come by, though both carry care warnings, as the former self-seeds prodigiously and the latter suckers. The most vivid sky blue is tweedia, Oxypetalum coeruleum, a shrubby perennial whose untidy growth habit is forgivable only because the flowers are so astonishingly blue. It prefers the colder winters and less humid summers of Sydney’s hills and west, where it can thrive in cottagey-style gardens where the dense and diverse planting disguises its form.

I have killed tweedia a number of times in a number of gardens, but have had better luck with the duck egg blue ixia, Ixia viridiflora, which is native to the Cape Province of South Africa. It grows from a corm and produces flower stems a bit like a gladioli, with flowers blooming up the stem in a delicate shade of turquoise with a dark eye.

At the moment my little clump of ixia is all leaves, but I’m hoping by the end of August the exquisitely surprising flowers will banish my lockdown blues.

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