Broom is a native plant that flowers in spring a few weeks after the gorse sets the countryside ablaze with its warm yellow flowers. The colour of broom is yellow too but a brighter, lighter shade of yellow, and it is just beginning to flower these days.
The ordinary broom, Cytisus scoparius, is a very impressive wild plant in flower, and it is not surprising that it has been brought into gardens.
Occasionally, among the general run of yellow-flowered plants, a red-flowered form arises. Some of these have been selected for use in gardens. 'Killiney Red' is one of these, with reddish flowers and darker red lower flower parts, sometimes also called the red broom.
It is a very good variety, bringing a blast of colour that can be used very effectively with other spring shrubs. It gets its name from the Watson nursery that once operated in the Killiney area of Dublin.
'Firefly' is another Irish variety with yellow and red flowers, raised in Co Down. 'Lena' has dark yellow and red flowers. A lovely variety with cream and pink flowers, 'Hollandia' is a softer colour, more subtle, and very abundant in flower.
The earliest of the lot to flower is 'Allgold', well-named for its all-yellow flowers which are produced in masses in mid-spring. There is a lovely pale yellow form called 'Warminster' which perhaps fits into the spring garden more easily.
A white-flowered form is sometimes seen and this is the Portugese broom, also called the white Spanish broom, Cytisus multiflorus. It looks the same as the wild broom but with manes of white flowers and it flowers a little earlier.
Broom is not long-lived. It is an opportunist plant in the wild, colonising bare ground, shedding seeds and dying out again when the competition from other trees and shrubs builds up.
In the garden after a few years it makes a big floppy bush, often splitting apart as soon as it grows to full size. But broom can be kept going for more years by pruning each year after flowering. If the green, rush-like shoots are shortened back to about five centimetres after flowering, the bush will take much longer to become straggly, and it will flower for many more years.
Broom likes dry sandy soil in full sunshine and it is a good choice for dry banks where it can be used to make some fast impact and allow slower growing trees and shrubs to take over the space after a decade or so.