It might feel increasingly cold and grey as we slide into autumn, but one species is in its full glory right now: the blowsy ivory flowers of gardenia (Gardenia jasminoides). Yet this exotic houseplant has much more to offer than mere visual appeal. Its creamy-white petals house structures that generate sweetly scented compounds which not only fill a room with their rich, jasmine-like fragrance, but according to recent trials may also have a profound effect on your mood.
Research on mice cells at Heinrich Heine University and Ruhr-Universität in Germany found that two of the compounds responsible for the scent of gardenia flowers could have a similar mechanism to commonly prescribed barbituates and anaesthetics such as propofol. They may even be of a similar strength under laboratory conditions.
Publishing their findings in the Journal of Biological Chemistry, the team further reported that in behavioral tests, simply inhaling such chemicals could markedly relieve anxiety and promote sleep (at least if you happen to be a lab mouse). The study’s authors are doing more research into this area, to establish if such findings may be replicated in humans, which could pave the way to the development of scent-based anxiety medications.
Remarkably, another scented compound found in gardenia, known as methyl jasmonate, can also be picked up by the nearby houseplants in your living room, through sensors in their leaves. The chemical was developed by plants as a warning signal to flag up to their neighbours that they were being attacked by pests such as aphids, so others could respond by boosting their defences.
A stunning flower that might just perk up both people and plants at this dingy time of year? I for one am getting out this week to pick up my own horticultural happy pill.
Growing gardenias
Gardenias make excellent houseplants as long as you can pander to their two simple (but nevertheless fussy) demands: ericaceous compost (like that sold for rhondodendrons and camellias) and a bright spot away from direct sun. A west-facing window in an average living room is perfect. Keep them well fed when in active growth (spring and summer) and on the dry side in winter. There are even a few hardy varieties resistant enough to be grown outdoors in some parts of the UK. ‘Kleim’s Hardy’ is my favourite.
Inside information
Eighty per cent of sugars are produced in tomato leaves, not fruit. Although thinning a few leaves can allow light and air to the fruit to assist ripening, I promise you total defoliation will knock flavour for six every time.
Email James at james.wong@observer.co.uk or follow him on Twitter: @Botanygeek
