Scotch broom

Synonyms: Жарновец метельчатый, Жерновец метлистый, Ракитник веничный, Ракитник метельчатый, Саротамнус метлистый, Cytisus scoparius (L.) Link, Sarothamnus vulgaris Wimm., Spartium scoparium L., Genista andreana Puiss., Genista scoparia (L.) Lam., Sarothamnus bourgaei Boiss., Sarothamnus oxyphyllus Boiss., Sarothamnus scoparius (L.) Wimm. ex W.D.J.Koch., Scotch broom, common broom, Scot’s broom, English broom.

Scotch broom (Cytisus scoparius (L.) Link) — a species of deciduous plants in the genus Cytisus of the family Fabaceae. The species was first described by the German naturalist and botanist Heinrich Friedrich Link in 1821-1822 in the book «Enumeratio Plantarum Horti Regii Berolinensis Altera» («Enum. Hort. Berol. Alt.»).

Photo: V. Kudelya. Germany

The native range covers practically all of Europe. Naturalized in Australia, Asia and North America. Grows in sunny locations near rocks, on sandy soils and heathlands, and at roadsides.

It is a shrub up to 3 m in height. Shoots are thin, green, pubescent when unfolding and later glabrous. Branches are angular and narrowly winged, erect or ascending.

Photo: A. Kovalchuk. Netherlands.

Leaves alternate, trifoliate, petiolate. Leaflets are oval or oblong-lanceolate, blunt, entire, 5-5 мм in length and 2-5 мм in width. Upper leaves often have a single leaflet.

Photo: S. Odinets. Ukraine

Flowers solitary or paired, located in the leaf axils, zygomorphic, papilionaceous, up to 2 cm long, pale yellow, fragrant. Flowers sit on long pubescent peduncles with underdeveloped, deciduous bracteal scales. The calyx is campanulate-funnel-shaped, pubescent, 4-5 мм in length, shallowly two-lipped. The upper lip has two closely set, short, ciliate teeth; the lower lip has three. The standard (with a claw) is 2-2,3 cm long, flat-helmet-shaped, glabrous, reflexed, broadly and almost rounded-heart-shaped, emarginate. The wings are equal in size, bluntly acuminate at the tip. The keel is broad, blunt at the apex, densely pubescent along the keel. Flowers abundantly and for an extended period in May–June.

Photo: S. Odinets. Ukraine

Fruits are narrowly oblong flattened pods 4-5 cm in length and 8-10 мм in width, hairy-white-ciliate along the sutures and glabrous on the sides. Seeds in the number of 2 or more, elliptic-ovoid, up to 3 mm in length, yellowish-gray.

Cultivars: «Dukaat», «Moonlight», «Andreanus», «Firefly», «Pendula», ’Burkwoodii’, ’Andreanus Splendens’, ’Killiney Red’

Subspecies:

· Cytisus scoparius subsp. maritimus (Rouy) Heywood
· Cytisus scoparius subsp. reverchonii (Degen & Hervier) Rivas Goday & Rivas-Martinez
· Cytisus scoparius subsp. scoparius

Hybrids: Cytisus × dallimorei Rolfe = Cytisus multiflorus (L’Her.) Sweet × Cytisus scoparius (L.) Link

Hardiness zone: zone 5-8 (-20°C).

Location / Site: very light-demanding. The best place for planting is an open area with southern exposure, preferably in locations protected from cold winds. Not recommended to plant near ponds with fish.

Pruning: after flowering it is recommended to cut back the faded shoots by half, without cutting into old wood.

Propagation: by seeds, which are sown in spring after a 2-month stratification, and also by softwood cuttings in summer. Cultivars can be propagated by grafting onto laburnum.

Soil: drought-tolerant, does not tolerate prolonged water stagnation or waterlogging. Does not like clay soil. Not demanding regarding soil fertility, can grow on any garden soil, including very poor soils. Prefers slightly acidic soil. Optimal soil pH is 6.5 — 7.5.

Planting: soil mix — one part sand and one part turf soil, peat-compost or humus; you can add a complete mineral fertilizer or Kemira-Universal (120 g per 1 m2). Does not like transplanting. Recommended spacing between plants — 30-50 cm. The root collar should be at ground level. Drainage is mandatory (on heavy soils — a layer of 15-20 cm, on light soils — 10 cm). After planting, mulch the root circle with soil or peat in a layer of 3-5 cm.

Care: does not require watering. For better flowering it is recommended to fertilize the plant twice a year — first in spring, second before flowering. In spring apply urea (20 — 30 g per 10 l water), in summer — 60 g of granular superphosphate and 30 g of potassium sulfate. To stimulate growth you can apply wood ash — 200 g per bush. Loosening not deeper than 8-12 cm.

Diseases: Powdery mildew (treat dormant buds with copper sulfate (5%); in summer regularly treat alternately with Fundazol, copper-soap solution, colloidal sulfur (0.8%)), Black spot (treat dormant buds with iron or copper sulfate; in summer spray with Fundazol, polikarbatsin (0.2 — 0.4%), copper oxychloride (1%), Captan (0.5%), Bordeaux mixture (1%)).

Pests: broom moth (spray with Chlorophos (0.2%)), broom looper (treat with organophosphorus or bacterial insecticides).

Companion plants: deutzia, birches, weigelas, mock orange, heather.

Uses: a good honey plant. One of the most popular species in Europe in areas with a mild climate. Used in large rock gardens, as solitary specimens on lawns, and when designing forest edges.