Unwanted lughole of top cat

"A tall, gangly, annual herbaceous plant with odd-looking flowers."

That's how Lion's Ear is introduced in Kew's picture guide to the plants and flowers of the world, Plant. The brief entry ends with a warning: "it should be monitored where grown to ensure it does not get into open countryside".

Native to South Africa, Leonotis leonurus is already invasive in at least southeast USA, Hawaii and Australia. In Victoria, there is an established population near Lakes Entrance as well as occasional reports of it escaping and establishing near gardens around Melbourne.

We grow it in Melbourne Gardens and I remember during my stint as a horticultural assistant in the early 1980s, my old colleague and friend John Beetham would irritate me no end by singing "Here comes Leonardo, Leonardo Lion..." from the 1960s cartoon show when ever this plant appeared on a census or in a garden bed we might be checking.

The usually yellow, orange or orange-red flowers (see above in the Karoo Desert National Botanical Garden) produce lots of nectar at the base of a long tube, an irresistible package of colour, shape and food source for sunbirds.

Similarly with another of the Leonotis species I saw in South Africa, this one bright red flowered and growing in a weedy verge of Kirstenbosch National Botanical Garden. I think it is Leonotis neptifolia, native to tropical Africa and India and appropriately for a December post, with the common name of Christmas Candlestick.

There are 13 others species of Leonotis, all from southern and eastern Africa. Leonotis leonurus is by far the most commonly cultivated. Outside gardens in South Africa it grows naturally among rocks in grassland, as it does in the landscaped garden of Karoo. 

As you've no doubt guessed, the genus name Leonotis has something to do with lions. Leon is Greek for lion and otis means ear. Hence, Lion's Ear, a reference to the hairy upper lip of each flower. The species name leonurus provides another connection to the giant cat. Urus means coloured, so a reference to the yellowy-orange flowers of some growth forms.

Just to keep this linguistic trail warm, a compound has been extracted from the leaves called leonurine - urine originally a Latin or Greek work for liquid or water. The plant has been used traditionally for a lots of ailments, from headaches to haemorrhoids. Chemical testing of the leaves has revealed properties to treat pain and inflammation.

Indeed, as noted on this sign in the Karoo National Botanical Garden, the Khoikhoi of south-western Africa smoked the leaves of this species for a "calming and euphoric effect". In fact in South Africa, they call the plant Wild Dagga, or in Afrikaan Wildedagga, from the slang for cannibis, although the effect are apparently 'very mild and not as potent'. 

The Karoo sign text helpfully adds that this plant is in the mint rather than cannabis family. It's also worth pointing out that subsequent studies on rats have shown damaging effects on red blood cells and death, so caution has been recommended in any use. 

That said, sucking the nectar from the flowers, as South African children will do, seems as safe as sucking it from the various weedy climbers growing around Euroa, as I used to do as a kid.