BLOOMS TO DRAW BIRDS
YOU’RE GUARANTEED MORE VISITORS TO YOUR BACKYARD IF YOU PLANT SOME OF THESE NECTAR-RICH NATIVE FLOWERS
The nectar-rich flowers of grevilleas attract honey-eating birds to the garden. Grevilleas range from low-growing ground covers to rounded shrubs, small bushy trees and even large trees like grevillea robusta.
They are generally fast growing and benefit from pruning, but many gardeners seem unsure of the timing and amount to remove.
There are three major types of grevilleas – and many hundreds of species.
Grevilleas interbreed freely and commonly produce “accidental” cultivars, or they are sometimes hybridised by human intervention.
Plant breeders then introduce them into nursery cultivation for garden use. Many new cultivars are registered with the Australian Cultivar Registration Authority, and those registered under a national Plant Breeders Rights Scheme are protected by a type of plant copyright.
Limited to commercial propagation and sale by selected growers, home gardeners will know these grevilleas by a small symbol representing the letters PBR on the plant label.
Like all members of the Proteaceae family, grevilleas have evolved on soils deficient in the nutrient phosphorus and applying fertilisers with more than very minimal ratios of phosphorus will either kill them or set their growth back seriously.
Grevilleas from Western Australia or inland are sometimes grafted onto a tough rootstock such as grevillea robusta to provide the extra vigour necessary to grow in the different environmental conditions of the eastern states.
A waterborne soil fungus called phytopthera cinnamomi is also an unfortunate risk to grevilleas, especially where drainage is poor.
This should not deter those keen to enjoy stunning flowers and the visiting birds.
Most grevilleas have their main flowering in late winter, spring and early summer. Pruning is best done at the end of the major flower flush, after rain or irrigation to ensure rapid regrowth. Pruning should be staggered to ensure birds don’t starve. Also prune off spent flowers from time to time to maintain a tidy habit. It is also important to maintain density and keep an even foliage weight distribution to prevent fast growing grevilleas from becoming top heavy and blowing over. Different forms require different pruning methods.
Grevilleas with needle like or prickly foliage and spider flowers make excellent hideouts for small birds but resent heavy pruning.
Maintain density by removing no more than 10 to 15 per cent of the growth at any time and cutting off spent flowers throughout the flowering time. Some grevillea flowers are one sided like a toothbrush, and should only be pruned up to a third if necessary to remediate their shape, but it’s preferable to trim about 10 to 20 per cent regularly.
Large brush-like grevilleas are grown for their spectacular flowers, sometimes literally dripping in nectar and a feast for birds.
Trim these after flowering, but avoid trimming prior to the late winter or early spring flush or the best of the flowering will be lost.
These grevilleas can be hard pruned, but it’s only necessary if they have become too large or misshapen, or following storm damage.
Some individuals are sensitive to grevilleas, so as a precaution gloves and long sleeves are recommended when pruning.
Grevilleas should have a place in every garden for their colourful flowers and the birds they attract. Regular care and sensible pruning will make their displays even more spectacular. Kate Heffernan is a horticulturalist, educator and honorary life member of Friends of the Gold Coast Regional Botanic Gardens. You can listen to her radio show Garden Talkback on ABC 91.7FM every Saturday from 9am. She has designed a tour for garden lovers in September 2018, including a cruise along the vine-clad rivers of Portugal and the South of France, stopping at historic villages and visiting gardens. Details at kateheffernan.com.au