Grevillea (Grevillea species)
Grevilleas are popular garden plants due to their showy blooms, long flowering and ability to attract nectar-feeding birds and other wildlife. Those with dense, prickly foliage provide perfect habitat for small birds. Flowering peaks in winter and spring, but continuous blooming is possible. Colours include red, crimson, pink, peach, orange, mauve, white, yellow and bicolour blooms. Grevillea, banksia, hakea and acacia make good companions as they are all intolerant of excess phosphorous, prefer sunny positions and generally demand good drainage.
There are over 450 species and subspecies, plus in excess of 140 registered cultivars to choose from. Check with staff at your local hardware or garden centre to find a grevillea that will thrive in your region.
- Pots, groundcovers and smaller gardens ‘Scarlet Sprite’, Royal Mantle, Grevillea lanigera Mt. Tamboritha.
- Shrubs and taller growers Robyn Gordon, Dorothy Gordon, Ned Kelly, Peaches and Cream, Ivanhoe, Loopy Lou, Molonglo, Misty Pink, Moonlight, Honey Gem, Superb and Grevillea banksia.
- Trees Grevillea robusta, Grevillea baileyana, Grevillea pteridifolia.
Growing conditions
Climate Breeding has resulted in varieties widely adapted to a range of climates. Ask staff at your local hardware or garden centre to recommend varieties if frost or summer rainfall and high humidity occur in your region. Ideally these beauties are sun lovers, so plant in full sun and keep sheltered from strong winds.
Aspect Full sun is preferred, but spiky, small-leafed selections (often G. rosmarinifolia and G. juniperina cultivars) tolerate light shade. Move potted plants during the year to ensure maximum sunshine. Good air circulation is essential. Plants with hairy or felt-like foliage are more susceptible to leaf disease. Stake young plants and shrubs in windy positions to prevent them blowing over.
Soil Grevillea generally demand perfect drainage. Mounding the soil to improve drainage is generally not a viable, long-term option on clay sub-soil (plant bottlebrush as an alternative). Where drainage is poor, grow in pots using a premium potting mix suitable for phosphorus-sensitive plants. Grafted plants have more robust root systems, extending successful cultivation across a wider range of climates and soil types. Grevilleas are sensitive to phosphorous found in poultry manure, mushroom compost and standard fertilizers and potting mix.
General Care
Watering Young grevilleas in well-drained soil enjoy regular watering. Seasol and Seasol Super Soil Wetter & Conditioner are beneficial during plant establishment; when it is dry or during other periods of stress. Mulch plants to keep the roots cool and retain soil moisture. Established plants require supplementary watering during long dry periods to promote healthy new growth and flowering.
Feeding Grevilleas are easily killed by excess nutrition. Avoid using poultry manure, mushroom compost and standard fertilisers due to excess phosphorous. Apply iron chelates to plants you think may be affected. PowerFeed with Troforte Plant Food All Purpose including Natives is suitable for grevilleas, apply once a season during the growing period or in the lead up to peak flowering and after pruning. Alternatively, you can boost growth with liquid PowerFeed PRO SERIES Plant Food All Purpose including Natives.
Pruning Tip prune young plants and lightly prune after each flower flush to remove spent flower stalks and seed pods. Where harder pruning is required, cut plants back by one-third immediately after peak flowering. Avoid severely pruning established grevilleas as they often lack the stored food reserves to support a new flush of growth.
Watch for Grevilleas endemic to your local area are likely to be longer lived than many cultivated varieties bred from species native to other regions.
Red leaf discolouration, leaf drop, interveinal yellowing and tip dieback are symptoms of phosphorous-induced iron deficiency. Apply iron chelate to assist in recovery.
Fungal leaf diseases occur on plants grown in shade or where soil or nutrition is unsuitable. EarthCare Rose Black Spot & insect spray will limit disease spread, but consider how you might make growing conditions more suitable so that plants become naturally more resistant.
Macadamia flower caterpillars attack grevillea blooms and hawk moth and looper caterpillars feed on foliage. Scale infestations are uncommon, but can occur. Apply Earthcare Natural Pyrethrum insect spray where pests occur. Take advice before using oil-based sprays as some sensitive grevilleas are prone to burning.
