‘Genista etnensis’ in its native habitat

My garden’s best shrubs of the moment are yellow flowered and minimally leaved. I do not think the family of broom bushes has many champions nowadays and the related family of gorse has even fewer. Nonetheless my winner this weekend looks like a broom and is botanically classed with gorse. It has no thorns or prickles and it throws off a great shower of bright flower. It is Genista etnensis, the Mount Etna broom, from the hot, volcanic Sicilian mountain. No wonder it likes excessive heat and drought. It was in its element in the recent days of debilitating heat in European gardens.

I first saw how good this tall shrub can be when I came across it in the early 1990s in the once-famous Irish garden at Malahide, a short bus ride from the centre of Dublin. Emerald Ireland was suffering in one of those hot Augusts of the early 1990s but the Etna broom was quite untroubled. In its heyday Malahide was celebrated for its collection of rare shrubs from Asia, Australia and New Zealand, amassed by Lord Talbot. They had dwindled over time but Genista etnensis remained a star in the diminished pack.

Shortly afterwards I visited Mount Etna and understood why this plant is such a survivor. The lower slopes of the volcanic mountain are covered in fine black grit, the lapilli of previous eruptions. The conditions are dry but surprisingly friendly to the right types of plant life. Genista etnensis is exactly the right type. Its thin, wiry leaves lose little water and do not need much more. The plants grow up to 15ft tall and erupt into their shower of yellow flowers when the Sicilian summers are starting to hit the heights of heat.

Back in Britain this genista was a favourite of Vita Sackville-West at Sissinghurst. She planted it cleverly in the back row of one of the narrow beds below her castle’s old brick walls and recommended it to her many readers for its cascades of flower, which reminded her of a Golden Rain firework. Not many readers followed her in this enthusiasm, possibly because the flowers were yellow at a time when strong yellows were becoming unfashionable. Worse, genistas belong to the dreaded family of gorse.

How restricting such fashions in flowers are. Gorse was thought to belong on down-at-heel hillsides in Ireland or Britain’s Celtic fringe. Actually, its strong orange-yellow flowers are extremely pretty there in early May. It was also thought to belong with hunting, not gardening. “There is never a story about foxhunting,” remarks a sceptical lady in one of the best short stories by the master-artist Saki, “which does not have gorse bushes in it.” Foxes still shelter from the wind in thick gorse coverts but a single bush in a garden is not going to interest them.

I was delighted to read that the Swedish founder of botanical naming, Carl Linnaeus, went down on hands and knees with delight when he first encountered gorse bushes on landing on the English coastline. “Swedes are always a bit odd,” said an American gardener when I told her this story but in this case they had kept their wits. I learned only recently, in Linnaeus’s centenary year, that the story of his thanks to God for prickly British gorse is a later legend. The expert historian Brent Elliott of the Royal Horticultural Society Lindley Library has even pointed out that Linnaeus would have seen masses of gorse in flower all along his route through Germany before he ever took ship for England.

Genista does not need any help from a Swede on his knees. It is the Planta genista of the old Plantagenet kings of England. As a result the related seedpods of broom-flowers are wonderfully visible on the robes of the courtiers and angels in the National Gallery’s great “Wilton Diptych”, the double painting of King Richard II and his earthly and heavenly attendants. My favourite genista, the Sicilian etnensis, has no prickles, no strong orange to its golden-yellow flowers and no appeal for foxes up on Etna either. It is simply a great shrub, ideally suited to a warming world and extraordinarily free with its little yellow flowers. It can be pruned, as I have found, by taking out the central stem and letting it spray sideways at a height of only 5ft or 6ft. Alternatively it will eventually make a tall, widely branched tree, up to 20ft but never so dense that it blocks out the light.

The biggest and best, in my experience, used to belong to a former professor of English architectural history in Oxford and in hot summers we would sit beneath its wiry curtain of leaves and flowers, beside the banks of limestone tufa-rock in which he grew alpines, his substitute for Sicilian lava. Wind can eventually knock a branch or two off a big tree but they are light and thin and do no damage if they snap. I think that an Etna broom would be an excellent choice for many other sunny back gardens.

Perhaps it has suffered by being muddled with a lesser substitute. Similar pea-shaped flowers, bigger and brighter, are found on a shrubby Spanish plant, Spartium junceum, known as Spanish broom. This item is only a shrub, never a tree, and has much more solid, pointed stems. It is good in its own right, especially in hotter summers and Mediterranean holiday gardens but it is not nearly so fine as the real genista.

I was surprised to hear from a nursery man that Genista etnensis had suffered from the recent cold winter. Outdoors it is totally hardy and I can only ascribe any losses in the trade to its over-wintering in vulnerable plastic pots. For nearly 20 years I have failed to kill it. I can give it no better recommendation for you all.