Brooms Are Beautiful: But Difficult To Tell Apart

One of the perpetual perplexities of my garden existence is how to tell a Genista from a Cytisus.

Beautiful BroomsPin

So when is it a broom and not a broom? 

Cytisus And Genista

It seems that in Cytisus, the flower parts (the “butterfly”) can be pulled apart separately, while in Genista, the petals are somewhat joined at the base. 

So that is the real key.

Cytisus is never spiny, but some Genista species are as spiny as gorse, Uk, another pea family member. 

And both have tiny simple leaves (or nearly none), like the false foliage of asparagus in summer, while others of either genus have three leaflets, like a woody clover. So it is quite confusing, right?

All brooms are native to Europe, but some have escaped this New World. Many are very hardy, but some cannot endure much-frozen ground. Cytisus may be 3′ feet or taller, but Genista species are never taller than two feet. 

The green foliage of Genista in some species has been used for a green dye, while the yellow flowers of both groups have been used for a yellow dye.

Most Common “Greenweeds” 

The most common of the “greenweeds” include:

  • Genista tinctoria
  • Dyers-greenweed or common woadwaxen 
  • A very slender shrub having green
  • Little twigs
  • Narrow, small, slender leaves, 
  • Always simple and narrow, 
  • Little terminal spires of yellow pea flowers were borne in June at 2′ feet. 

Used for both green and yellow dye, it was planted in Salem, Mass., by the first settlers, at the example of the wife of Governor Endicott, in 1830. 

Genista: Common Escaped Plants

It is a common escaped plant in sandy sunny fields north of Boston, even into New Hampshire.

Similar are Genista pilosa and Genista cinerea, with fewer flowers scattered among the narrow leaves. 

Genista Sagitialia: Flat And Two-Winged Twigs

Genista sagitialia is nearly flat to the ground, the twigs two-winged, with many deep yellow flowers in terminal clusters appearing in June. This is an excellent small rock shrub, like a depressed woody yellow clover. 

Other simple-leaved species are spiny, differing from the usual woad-waxen because of sharp spines, and are as companionable as a wild rose or a gooseberry bush. 

Genista Germanica And Genista Anglica

Genista germanica and Genista anglica have narrow terminal clusters of flowers, while Genista hispanica has flowers in a dense head, like a yellow clover.

Other species have the same three leaflets as do many Cytisus. 

Genista Nyasana, Radiata, And Horrida

Genista nyasana has flowers in narrow racemes (somewhat like Genista tinctoria), but with three leaflets, and is not spiny. 

Genista radiata has 3 leaflets, the twigs horizontal like a tiny pin oak, and the flowers in clover heads. 

Genista horrida is the climax, with three leaflets, very spiny twigs, and clover heads of little yellow flowers. It is a pin-cushion full of needles and is less hardy than most species.

Genista: Simple Leaves

Nearly all these are growing in the Arnold Arboretum, confusingly alike, with yellow flowers in June. 

Some have simple leaves; some have three leaflets. Sonic is spiny; others are unarmed, and Genista sagittalis has winged little twigs. All are suitable for a sunny, sandy rock garden.

Cytisus: Brooms

Cytisus, the true brooms, are more variable and often taller.

But, by far, the most common is Cytisus scoparius, Scotch broom, very slender and erect to 6′ feet and more, the twigs, very green, with few small leaves of three leaflets, remaining green all the year. 

In May-June, many rather large yellow flowers are solitary along the stems.

Although a European plant, it is now wild in New England and our northwest Pacific Coast, usually in sandy fields and often near the sea. 

So popular is it for its Spring bloom and evergreen twigs that there are forms with pale yellow flowers, crimson wings, or double flowers.

It is one of the tall species, and the golden flowers are as large as the blossoms on garden peas.

Cytisus Multiflorus

Cytisus multiflorus is similar in growth but bushier, and while many of the leaves are three-parted, the upper ones are simple. 

The flowers are small, white to palest yellow, in great profusion along the slender arching stems, with a pronounced “boiling beans” odor. 

This shrub can reach 10’ feet, with widely spreading branches. It is not too hardy in zero weather.

Cytisus Purgans: Very Bushy Dark Shrub

Cytisus purgans is a very bushy dark shrub to 3′ feet or more, and as much in the spread, the stems dark green, and the small, simple leaves absent or son falling. 

The plant has the color and form of a stunted mugo pine. Many deep yellow bean flowers are all over the stiff dark twigs in May, with the usual bean odor. 

In sandy soils, it gives the bulk of the taller dwarf junipers and blooms in a sea of custard yellow.

Cytisus Decumbens And Procumbens

Cytisus decumbens is flat on the ground (Cytisus procumbens is a lot taller), with stiff stems and simple leaves. 

There is more than the normal amount of foliage, and the foliage hides the scattered flowers. 

Varieties Of Flower Clustered Cytisus

With flowers clustered at the ends of leafy shoots, with 3 leaflets, at 6 feet, are: 

  • Cytisus nigricans with the flowers in slender racemes or 
  • Cytisus sesibfains with flowers in more clover-like heads.

Slender Tubular Flowers

With more slender tubular flowers in narrow terminal, spires are such as:

  • Cytisus supinus, at 3′ feet., with the usual three leaflets very silky or 
  • Cytisus austriacus with shorter hairs, while Cytisus albus has white flowers. 

Yellow Clovers Leaves

These three looks like yellow clovers grown into shrubs, or the flowers are scattered along the twigs among the leaves, including:

  • Cytisus hirsutus
  • Cytisus elongalus
  • Cytisus ratisbonensis

The clover leaves are more abundant than the flowers, or we have the tender Genista canariensis, often called a “genista,” which is grown in northern greenhouses for Easter bloom, hardy in lands of little frost.

Show-Off Flowers

These I have tried to list somewhat in order of show-off flowers.

Cytisus scoparius and Cytisus multiflorus (and their hybrids) really are loaded with flowers. 

Cytisus purgans is a bushy juniper with many pea flowers and the usual bean odor. 

The others are less important as producers of flowers, but all are showy and worthy.

Cytisus Purpureus

There remains as climax Cytisus purpureus, scarcely a foot tall, with clover foliage, but the flowers are deep purple, pale purple or pink, or nearly white, all with little odor. 

Since all brooms supposedly have yellow flowers, this plant must be a mistake on the part of nature, but it is an excellent small shrub for the sunny rock garden.
44659 by Stephen F. Hamblin