A low growing shrub to about 1 metre tall, spreading to 3 metres wide.
This cultivar was introduced by Richard Tomkin at Changers Nursery in Queensland. It is reportedly a hybrid between G. nana subsp. abbreviata (a near-threatened taxon in WA) and G. ‘Sid Cadwell’. Since its creation, plants have been grafted onto G. robusta to enhance its reliability.
It has leaves to about 15 cm long x 8 cm wide, which are finely dissected (pinnatisect) with very narrow linear segments about 4 cm long and only 0.1 to 0.2 cm wide, given a fern-like appearance. The leaf-segment tips have sharp points. The foliage is densely produced.
A grevillea inflorescence is technically a cluster of paired flowers, termed a conflorescence with the overall structure forming a raceme-like appearance.
Grevillea species exhibit 3 main inflorescence structures:
1. A cylindrical to ovoid raceme (with flowers emerging around a 360° radius)
2. A single-sided raceme (with flowers produced on only one side, resembling a tooth-brush)
3. A condensed or clustered raceme (usually as long as it is wide, with species referred to as the spider-flowers).
Grevillea mostly produce the inflorescences at the terminals, beyond the foliage, which differs to the closely related Hakea.
This cultivar has cylindrical inflorescences, to about 20 cm long by about 8 cm wide. They are mainly bright metallic pink in colour. In bud, they are grey-green.
It reportedly flowers most of the year.
Individual flowers are composed of 1 carpel (female part) where the style and stigma protrude out; 4 stamens hidden away in the perianth; and the perianth (petals and sepals collectively) which connects to a pedicel. Proteaceae flowers do not have any discernible petals or sepals (having only one whorl) and so these are referred to as “tepals” of which there are 4. In this cultivar, the carpels are to 40 mm long, metallic pink with pink tips. The perianths are also metallic pink with the hairy grey-green pedicels.
A very attractive shrub, only growing to 1 metre of so tall. It has an ability to spread wide than it is tall.
It can be rounded and made very dense with light pruning and made into a short umbrella-like form.
Grow in an open sunny to part-shade position. Reported to be hardy once established if a grafted form is used. Additional watering will promote flowering. However, it tolerates dry conditions.
Can be used as a low screening hedge.
Grows best on sandy soil with fast drainage. It is frost tolerant once established. Great for attracting birds.
Grevilleas are propagated by three principal methods; seed, cuttings and grafting. To maintain desirable characteristics of a particular plant, vegetative propagation (e.g. cuttings or grafting) must be used. This also applies to propagation of named cultivars.
Grevillea is a diverse genus of about 360 species of evergreen flowering plants native to rainforest and more open habitats in Australia, New Guinea, New Caledonia, Sulawesi and other Indonesian islands east of the Wallace Line. NSW currently has about 85 species although with a lot of subspecies and some informal taxa recognised.
Grevillea flowers were a traditional favourite among First Nations Peoples for their sweet nectar. This could be shaken onto the hand to enjoy, or into a coolamon with a little water to make a sweet drink. They might be referred to as the original “bush lollies”.
This is commonly sold as a grafted plant, using G. robusta understock, on the East Coast for better reliability.
Grevillea – was named in honour of Charles Francis Greville (1749-1809), an 18th-century patron of botany and co-founder of the Royal Horticultural Society. He was also a British antiquarian, collector and politician who sat in the House of Commons from 1774 to 1790.
‘Billy Bonkers’ – reportedly named after Richard Tomkin’s pet dog.
Gardening with Angus – Grevillea ‘Billy Bonkers’ profile page https://www.gardeningwithangus.com.au/grevillea-billy-bonkers-grevillea/
Burke’s Backyard – Factsheets – Grevillea ‘Billy Bonkers’ https://www.burkesbackyard.com.au/fact-sheets/in-the-garden/flowering-plants-shrubs/grevillea-billy-bonkers/