Cytisus scoparius Seeds | Broom
LATIN NAME: Cytisus scoparius
COMMON NAME: Broom
Plant Profile
Broom is a deciduous shrub of one to three metres with long green angular stems that carry out most of the photosynthesis, small trifoliate leaves that fall early, and yellow pea flowers in late spring. The whole plant is stiff and brush-like, which is exactly what the name describes.
It grows on heathland, railway banks and sandy ground across Europe, and it was carried to New Zealand, Australia, South Africa and the American west, where it became one of the worst scrub weeds of pasture and plantation. In Britain it is a native of the heath and a plant of the railway cutting. The flowers are set in the axils of the previous year’s growth, and a hard cut in winter removes the wood that would have carried them.
Science & Biotechnology
The green stems are the plant’s answer to drought and to poor soil: they are ribbed, waxy and carry the stomata in grooves, and they keep working through a dry summer when the leaves have dropped. That is also why the plant is flammable, since the stems contain resins and burn hot even when green.
Seed survives in the soil for decades, and a single plant can produce thousands of seeds that are ejected from the pod with a audible pop on a hot day. Fire and disturbance trigger germination, so clearing a stand by burning guarantees the next generation. Biological control with the psyllid Arytainilla spartiophila and with seed beetles has had partial success in New Zealand.
Uses & Benefits
The stems were cut and bound for brooms and brushes, and the plant gives the English word. The flowers and tops were used in country medicine as a diuretic and for heart complaints, a use that rested on the alkaloid sparteine, which is now a prescription antiarrhythmic and is toxic in the wrong dose.
The plant is grown in gardens for its early yellow flower on poor, acid soil, and it is one of the best shrubs for a sandy bank. The branches are also used for thatch pegs and for kindling. It fixes nitrogen, which is why it colonises bare ground so effectively. The seed is also roasted as a coffee substitute in some districts, a use that goes back to the years when real coffee was out of reach.
Growing from Seed
Scarify or soak the seed, since the coat is hard, and sow in spring at eighteen to twenty degrees. Germination is fast and uneven, and the seedlings should be potted on before the taproot coils.
Plant out in full sun on acid, sandy or stony soil, and do not add compost, which makes the plant leggy and short-lived. Cut the stems back by a third after flowering to keep the bush dense, but never cut into old wood, which does not reshoot. The plant is short-lived at ten to fifteen years and should be replaced from seed or cuttings.
Our Take
A bright, fast, short-lived shrub for poor acid ground, and a serious weed wherever it has been introduced. Grow it where it can be cut back.
Related Reading
More species in the same orbit as Broom: