There are more grevillea species in Australia than there are days in the year, and every year a few more join the gang as botanists and dedicated volunteers find previously undescribed plants. In the Sydney basin alone there are more than 30 different species, most coming into their peak flower period about now. You can see them, and a few hundred other grevillea species, hybrids and cultivars at the Illawarra Grevillea Park. Ray Brown is the energy behind the park, which is maintained by volunteers, and opened to the public a few weekends a year.
Brown is a member of the Australian Plants Society’s Grevillea Study Group. Together with other enthusiasts he collects plant material and specimens in the wild, experiments with propagating and grafting plants, and trials them in the gardens at the Grevillea Park. There is plenty to learn. After 200 years what we don’t know about Australian flora totally outweighs what we do know.
One thing we know is that it is much easier to grow grevillea cultivars in the garden than the species. The garden-proven, large-flowered grevilleas are great garden plants for screening or for standing tall at the back of a border. Most popular are cultivars such as bronze-orange ‘Honey Gem’; pink ‘Peaches and Cream’ and ‘Flamingo’; yellow ‘Moonlight’ and red ‘Robyn Gordon’. ‘Robyn Gordon’ has a notorious reputation for causing screaming allergic reactions, but she shouldn’t be singled out. Gardeners who are sensitive to the tiny hairs on grevilleas will be sensitive to all of them and should stay well away, or cover up completely. Those of us who don’t come out in a rash around grevilleas can welcome these plants into gardens for the dramatic, nectar-dripping, almost-year-round flowers, and the birds they attract.
The key to having them look good in the garden is to prune annually, which will also extend the life of the plant. At the end of September cut off all the flowers and put them in a vase, then cut the plant back to waist or chest height; knee-height for ‘Robyn Gordon’. You’ll see new growth within a fortnight and the plant will soon be flowering again. Plants that have been left to grow unpruned and have become lank and straggly can be given a rejuvenation prune in spring, right back into hard wood at chest height. The only rule, says Brown, is to avoid pruning when the weather is wet or very hot.
Grevilleas, like other members of the proteaceae family, are highly sensitive to phosphorus, the plant nutrient that boosts development of flowers, fruit and seeds in common garden plants. So feed them with a low-phosphorus slow-release fertiliser developed for native plants, and water during very dry weather in the growing season.
The Illawarra Grevillea Park is open September 5-6 and 12-13. Grevillea Park Road, Bulli. There will be plants for sale, including ‘Bulli Beauty’, which appeared in the park as a seedling and has dense ferny foliage and pink toothbrush flowers. Details: www.grevilleapark.org.