Plant profile: Cytisus scoparius (Scotch Broom)

Latin name: Cytisus scoparius ("sigh-TISS-us sko-PAR-ee-us") 
Common name: Scotch Broom, Common Broom
Originally from: The UK
Blooms: Covered in yellow flowers in spring.
Light: Full sun to part shade
Water: Rain is plenty. No summer water!
Height x width: 3' to 9' tall x 3' to 5' wide
USDA Zones: 5-9
Where to find in P. Garden: One appeared in the brights bed.... and flourished.

As a legume, these shrubs fixes nitrogen in the soil by a symbiotic relationship with Rhizobium bacteria. When their leaves fall they improve the quality of your soil, which helps other plants to grow. How nice, you think!

Sadly, not everyone is happy to see a broom growing. Cytisus scoparius has been introduced into several other continents and is classified as a noxious invasive species in California and the Pacific Northwest in North America, in Australia, New Zealand and India.

It is estimated that it is responsible for $47 million in lost timber production each year in Oregon. In New Zealand broom the species estimated to cost the forestry industry NZ$90 million and farmers NZ$10 million. Biological control for broom has been investigated since the mid 1980s with a number of species being tried out, like the broom twig miner (Leucoptera spartifoliella), the broom seed beetles (Bruchidius villosus) the broom gall mite (Aceria genistae) the sap-sucking broom psyllid (Arytainilla spartiophila) and recently the broom leaf beetle (Gonioctena olivacea) and the broom shoot moth (Agonopterix assimilella).

All with limited success.

Several cultivars selected for variation in flower color, including "Moonlight" with pale yellow flowers, "Andreanus" and "Firefly" with dark orange-red flowers, and growth habit, including "Pendula" with pendulous branches. Our one is the plain yellow type - nothing fancy.


UPDATE: Sadly this plant died after 5 years of drought. It was darn tough though! 

UPDATE TO THE UPDATE: It didn't die! It grew back the next year... wow.