Cultivars
Note many of the cultivars do not have fragrant flowers. 

'Burkwoodii'
This plant has garnet red and yellow flowers.

'Donard Seedling'
This plant has purple-rose and pink flowers.

'Firefly' 
This plant has yellow tinted with bronze flowers.

'Johnson Crimson'
This plant has crimson flowers on arching stems.

' Lord Lambourne'
This plant has bicolour yellow and maroon flowers.

'Windlesham Ruby'
This plant has ruby-red flowers.

'Fragrans'
This plant has bright yellow flowers that are fragrant.

'Lilac Time'
This plant has soft lilac flower.

'Alba'
This plant has small white flowers.

Cytisus x spachianus “Cytisus”, from Greek Kythnos, an island where several species are found; “spachianus” commemorates nineteenth century French botanical author Edouard Spach.
It was derived from Cyisus canariensis x Cytisus stenopetalus.

This cultivar forms a rounded shrub with a short trunk; the alternate trifoliate leaves are shiny dark green and pubescent on the underside. 

It flowers during early to late spring with deep golden pea-shaped flowers that occur in terminal racemes and has simular environmental requirements as Cytisus scoparius. 
In some areas it has become a serious weed problem and it is advised to remove the pods from the plant as they appear. In Australia it is not recommended to be planted.  Warning if the pod or seeds are eaten it will cause stomach upset.

Weed Potential 
As a weed Common Broom is a highly invasive in cool high rainfall regions invading habitats including alpine grasslands or moist woodlands and forests or along water courses. It inhibits the development of native tree or shrub seedlings and prevents ground flora from growing. The shrub grows in fertile moist well drained soils and prefers an open sunny position but will tolerate some shade. 

Plants produce seeds with in 2-years and may live for up to 25-years. The very viable seeds are released explosively up to 4.5m (14ft) from the parent and can remain dormant in the soil for up to 20-years. 

Disturbance of the soil under the shrub encourages a mass of seeds to germinate and Common Broom fixes nitrogen in the soil adding fertility and encouraging seedling growth. The seeds are dispersed by birds, ants, animals or on machinery and in garden waste or in soil.

Control methods include physically digging out seedlings checking that all the roots are removed. Shrubs with fruiting branches should be bagged and removed off site. 

They may also have the trunk scraped or drilled, then paint with a non-selective herbicide. Small plant or seedlings may also be sprayed with a non-selective herbicide but a follow up spray will be required as it take many years to eradicate accumulated seeds in the soil.