Synonyms: Warminster broom, Cytisus osbornii R. N. Notcutt, Cytisus praecox var. albus T. Sm., Cytisus purgans (L.) Benth.
Early broom (Cytisus praecox Beauverd) — a species of deciduous plants in the family Fabaceae. An interspecific hybrid Cytisus multiflorus × Cytisus purgans. It was obtained by the American entomologist and myrmecologist William Morton Wheeler in 1867 in Warminster (England). It was first described by Swiss botanist Gustave Beauverd in 1897 in the journal «The Gardeners’ Chronicle». In cultivation since 1867.
Cultivar 'Hollandia'. Photo by V. Kudelya. Germany
It is a perennial deciduous shrub with a spreading, flat, irregular and densely branched crown. It reaches 0.7-1.5 m in height and 1.2-2 m in width. Branches are very numerous, erect from the base, spreading or ascending, later becoming pendulous to sprawling, thin, ash-green in color, glabrous. Shoots are initially pubescent.
Cultivar 'Allgold'
Leaves simple, alternate, 0.8-2 cm in length, obovate-lanceolate, linear-spathulate to almost linear, silky-hairy, herbaceous green, falling early. Stipules absent or caducous.
Cultivar 'Allgold'
Flowers borne singly or in pairs in leaf axils, densely arranged along the entire length of the shoot, very fragrant. Calyx 5-lobed, bilabiate, glabrous. Corolla small, papilionaceous. Petals clawed, orange or yellow, the standard broadly rounded. Wings narrow, obovate-lanceolate to oblong, wing tips blunt or rounded. Stamens 9-10. Blooms in May-June.
Fruits elongated to elliptical pods, with 11 seeds inside. Seeds ovate, olive, brown or black in color.
Cultivars: ’Warminster’, ’Allgold’, ’Boskoop Ruby’
Hardiness zone: zone 5-8 (down to -29°C).
Location: very light-loving. The best place to plant — an open area with southern exposure, preferably in locations sheltered 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, avoiding old wood.
Propagation: by seed, sown in spring after a 2-month stratification, and also by green cuttings in summer. Cultivars can be propagated by grafting onto broom.
Soil: drought-tolerant, does not tolerate prolonged water stagnation or overmoisture. Does not like clay soil. Not demanding in soil fertility, can grow on any garden soil, including the poorest. Prefers slightly acidic soil. Optimal soil pH 6.5 — 7.5.
Planting: soil mix — one part sand and the other 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 at ground level. Drainage is mandatory (on heavy soils — layer of 15-20 cm, on light soils — 10 cm). After planting, mulch the trunk circle with soil or peat in a layer of 3-5 cm.
Care: does not require irrigation. For better flowering it is recommended to fertilize the plant twice a year — the first time in spring, the second — before flowering. In spring apply urea (20 — 30 g per 10 l of 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 shrub. 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, Polycarbacin (0.2 — 0.4%), copper oxychloride (1%), Captan (0.5%), Bordeaux mixture (1%)).
Pests: broom moth (spray with chlorophos (0.2%)), broom geometrid (treat with organophosphate or bacterial insecticides).
Companions: deutzia, birches, weigelas, mock orange (Philadelphus), heather.
Uses: a good honey plant. Widely used for decorating sandy slopes, creating protective hedges and borders. Shows well in solitary and group plantings.
