'Scotch Broom' - the name conjures up images of broad, lonely moors, with constant wind crying eerily around a large mouldering mansion occupied by dark, brooding people embroiled in romances, love triangles, mysterious family curses, and lives more complicated than any modern soap opera ever dreamed of - the stuff of Victorian novels and consumptive hallucinations. But in fact, Cytisus scoparius, Scotch Broom, is a very real, delightfully cheerful and tough shrub, that is perfect for modern gardens on both sides of the Atlantic.
Scotch Broom is a multi-stemmed, fine textured shrub with many, slender, upright arching stems that are bright emerald green twelve months of the year (similar to those of Winter Jasmine, Jasminum nudiflorum). Leaves are also a bright cheerful green and are tri-partite (divided into three lobes) so that the stems appear covered with hundreds of narrow clover leaves. Cytisus scoparius will reach anywhere from 5 to 10 feet in height with a spread of 5 to 8 feet, depending on the site. The bright green stems are wonderful in the winter garden and a graceful addition to a mixed border during the summer, especially as they retain their good, fresh green color through the tail end of summer when many other shrubs have begun to look rather tired.
The time of the year when Scotch Broom literally shines is late spring when the stems are completely covered with brilliant gold to pink to red blooms (depending on the cultivar). These flowers are similar in shape to those of Sweet Peas and can be so dense that they appear to be spontaneous rockets of bloom erupting from the ground, unattached to any stem or root. There is absolutely nothing 'brooding' about Cytisus scoparius in flower, it is a fiesta of sparkling color, a shower of glowing gold that makes an incomparable statement in the garden.
Scotch Broom is a tough plant in the landscape. Native to the dry soils of central Europe, it will do very well in poor, sandy soils where other showy shrubs will remain stunted and suffering. However, this shrub has also performed well in the heavier, clay soils of the North Carolina Piedmont at The NCSU Arboretum (now the JC Raulston Arboretum). It is a good candidate for many tough sites, especially where salt and drought tolerance are required. In fact, it is so well adapted to dry, poor soils that regular water and fertilizer can actually shorten its life. Scotch Broom needs full sun and should be transplanted as a container-grown plant. If pruning is desired, stems should be cut shortly after flowering is finished. Scotch Broom is completely cold hardy from the coast to the mountains of the southeast but may suffer some dieback during severe winters in the mountains. It can be propagated from stem cuttings taken during summer and rooted under mist but cuttings should be treated with high concentrations of rooting promoter before rooting.
Scotch Broom is a very popular garden plant in Europe where there are scads of cultivars available. Here in the US however, the plant is much less commonly found with only a few of the cultivars turning up on a regular basis. However, there are increasingly more selections being produced and it is well worth the trouble to look for the wonderful range of colors available in the many named forms. Some of these cultivars include 'Burkwoodii' with light red flowers, 'Carla' with light pink flowers lined with white, 'C.E. Pearson' with rose, yellow and red flowers, 'Cornish Cream' with cream to buff blooms, 'Dorothy Walpole' with rose flowers whose wings are deep red, 'Firefly' with two tone flowers that are gold and deep burgundy, 'Goldfinch' with yellow and scarlet flowers, 'Johnson's Crimson' with scarlet blooms, 'Killeny Red' which is dwarf form with bright red flowers, 'Knaphill Lemon' with lemony yellow flowers, ''Minstead' with magenta and white flowers, 'Moonlight' with creamy yellow to white blooms, 'Nova Scotia' which is an especially hardy form with brilliant yellow flowers, 'Red Favorite' which is a compact form with fire-engine red flowers, and 'Zeelandia' with pink flowers on especially long, arching branches.
There are also a great many other species and hybrids of Cytisus that may be found with some hunting. Some that you might encounter are C. procumbens and C. decumbens, both of which are aptly named groundcover types with bright gold flowers, the dwarf C. hirsutus, Hairy Broom, which is the most cold hardy of Cytisus, C. multiflorus, a white flowered broom, and C. x praecox, Warminster Broom, which is hybrid of complex parentage with a number of named forms in a range of colors. Two closely related genera are Genista (Woadwaxen) and Ulex (Gorse). Genista, like Cytisus, is a topic unto itself, while Ulex europaeus is generally the only species of Ulex seen in gardens. Gorse is a somewhat coarse and unbelievably spiny shrub similar to Cytisus in most other aspects, except that it generally flowers earlier than Cytisus in the southeastern US.
Scotch Broom is one of the most brilliant bursts of color in the landscape during its peak br> display in the spring, but it also blooms sporadically throughout the summer and into fall adding touches of intense color to a border or corner of the garden for months. It is an absolute show stopper in combination with other flowering shrubs and perennials, and is marvelous against stone walls. Scotch Broom's masses of color stand up beautifully to the intense light of the southeastern landscape - a light that can turn a less brilliant display into a washout in full sun. At The NCSU Arboretum (now the JC Raulston Arboretum), Cytisus is dazzling in a number of gardens, including the beds outside of the Shade House. As you walk through the Arboretum, the brooms are easy to see, even from a distance, as a wonderful glow of color in the landscape - a familiar, Carolina landscape without even a hint of moor or wuthering mansion in the distance......