A friend posted a photo of Backhousia citriodora on Facebook, asking if anybody knew what it was. I was promptly reminded of my plant and rushed out to pick some of the leaves to flavour the batch of kombucha I was just preparing. For it has one of the strongest lemon scents of any plant I know – eclipsing even grated lemon peel – and is edible.
It is an Australian tree, the lemon myrtle. Its natural habitat is tropical rainforests of central and southern coastal Queensland but it is also an important commercial crop, grown for its very essence of lemon. Fortunately for us, it is not so tropical that it needs to be grown in frost-free conditions though it is presumably happier in milder areas of this country. Apparently it can reach 20m in height though that may be it stretching itself to reach the light in forest locations. In a more open position, ours is hovering around 3 metres but I do cut it back from time to time to keep it more compact. It does not seem to mind being trimmed.
There are more distinctive trees, if I am honest. We used to grow both B. citriodora and its relative B. anisatum (now Syzygium anisatum) and the less popular aniseed flavoured myrtle had the more attractive foliage. But at this time of the year, the lemon myrtle is in full flower and I came across this specimen in the Te Henui cemetery yesterday. It was alive with bees and a wondrous sight and sound. The fluffy clusters of flowers and stamens have their own charm, in a gentle sort of way.
I have used the lemon scented leaves to flavour milk-based dishes that lemons would curdle and added it to my fresh harvest of green tea. The kombucha won’t be ready for another five days so I can’t comment yet on how strongly lemon flavoured it is but I see no reason why it will not be effective. I have not tried drying the leaves but the ever-handy internet tells me they retain their lemon aroma when dried. Indeed, Wikipedia gave the following helpful advice: “The dried leaf has free radical scavenging ability”. So now you know.
It appears that lemon myrtle is particularly vulnerable to the dreaded myrtle rust in Australia which has implications for commercial growers and for the plant in its natural habitat. It remains to be seen whether rust-resistant varieties appear but I have not heard reports of it being spotted in NZ yet. Mind you, it is not a common tree here but it is worth growing one in the edible garden alongside the more common but dull bay trees – Laurus nobilis. Unlike the bay, which gets thrips, I have never seen anything much attack the backhousia and I find I need lemon flavouring way more often than I cook with bay leaves.