Grevillea
( greh - vil - LAY - uh )
At-A-Glance Information
Grevillea, commonly called Spider Flower, Silky Oak or Toothbrush Plant, is a genus of evergreen shrubs and trees mostly native to Australia. Take care when planting these plants in your yard, as the leaves of some species can cause skin irritations and rashes. Use these shrubs as screening plants, groundcovers, or as subshrubs in mixed planting beds. Some species can also be used as quick-growing trees. The flowers will attract butterflies, bees, and hummingbirds to your garden.
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Grevillea Species and Varietals
The Grevillea genus is included in the Proteaceae family of plants and has 350 species. The genus is named for 18th-century botanist and co-founder of the Royal Horticultural Society, Charles Francis Greville. The ideal growing zones for Grevillea vary, depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.
Grevillea alpina (Mountain Grevillea) This species of shrub varies in size and form, and grows well in zones 9 and 15-24. These shrubs need light shade to full sun; variety 'East Grampians' is a compact selection reaching just 2.5 feet tall and twice as wide, with green leaves and yellow-red flowers that bloom from fall through springtime. |
Grevillea australis (Alpine Grevillea) This shrub does well in zones 15, 16, 23 and 24 and has an erect, spreading habit. It grows to about 7 feet tall and 9 feet wide, with small, dark green to olive green-colored leaves and off-white flowers. Not a profuse bloomer, but blossoms are strongly fragrant, blooming winter through springtime. Needs full sun to partial shade and moderate water to perform well. |
Grevillea banksii Best in zones 16-24 and H1, this shrub or tree reaches 9-25 feet tall and 6-12 feet wide with an open habit. Leaves are dark green and deeply cut, and flowers are dark red, blooming year-round (most profusely in springtime). Hardy to 24 degrees Fahrenheit. Needs full sun and moderate water. |
Grevillea 'Bonfire' This shrub is best in zones 8, 9, 14-17, and 21-24, and has an upright, rounded form reaching 4-6 feet tall and 6-8 feet wide. Leaves are bright green and somewhat feathery, and flowers are rose-red and shiny. Blooms most profusely in springtime, but flowers continue through fall. Needs full sun to partial shade. |
Grevillea 'Canberra Gem' This species takes the form as a shrub and grows well in zones 8, 9 and 14-24. It reaches 8 feet tall and 12 feet wide, and has a graceful, open habit and needlelike green leaves. Great as a barrier plant. Produces clusters of red flowers in winter and springtime, intermittently throughout the rest of the year. Needs full sun to partial shade. |
Grevillea 'Fanfare' ('Austraflora Fanfare') This shrub grows well in zones 15-24 and has a low, spreading habit to a foot tall and 10-15 feet wide. Leaves are copper-red and fuzzy when emerging, and mature to dark green. Deep red flowers bloom in winter through springtime. Great groundcover; tip prune after flowering to keep a dense habit. Can be grown in full sun or partial shade. |
Grevillea lanigera (Wooly Grevillea) This shrub is best in zones 15-24 with a spreading, mounding growth to 3-6 feet tall and 6-10 feet wide. Foliage is greyish-green and flowers are cream and crimson, blooming in winter and springtime. These shrubs are great as bank covers, and there are many varieties that do well in rock gardens or as groundcovers. These shrubs need full sun to partial shade and can tolerate extended periods of moisture. Varieties include 'Low Form' (to 2 feet tall and 4 feet wide, good for containers), 'Coastal Gem' (to 1.5 feet tall and 4-5 feet wide), and 'Mount Tabitha' (to 2 feet tall and 4-6 feet wide). |
Grevillea lavandulacea (Lavender Grevillea) This shrub has varying sizes and habits, and grows well in zones 15-24; grey foliage. Grow in full sun to light shade. Varieties include 'Billywing' (2.5 feet tall and 6 feet wide with cream and red flowers), 'Penola' (to 5 feet tall and 12 feet wide, with rose-red blooms fall to springtime), and 'Tanuda' (1.5-3 feet tall and 3-6 feet wide, with coral pink flowers). |
Grevillea 'Moonlight' This shrub is best in zones 15-17 and 21-24, and has a soft look to it. Leaves are dark grey-green and fernlike, and flowers are cream to pale yellow, blooming in winter and spring. Great as cut flowers. Shear or cut back these shrubs to encourage fresh new growth and more blooms by about a third after flowers fade. Needs full sun to partial shade to flower well. |
Grevillea 'Noelii' This shrub is best in zones 8, 9, and 12-24, and reaches 4-5 feet tall and 5-8 feet wide, with needle-like green leaves. Flowers are pink and white, and bloom in springtime. These shrubs are easy to grow and make a nice hedge when grown in full sun to partial shade. Can be sheared. |
Grevillea 'Poorinda Signet' This species grows as a shrub in zones 8, 9 and 14-24, and has a dense, spreading habit. Leaves are dark green on top, grey-green underneath, and flowers are coral-red, blooming in late spring through wintertime. Hard prune when young to encourage a bushier habit. Needs full sun to light shade. |
Grevillea robusta (Silky Oak) This tree does well in zones 8, 9, 12-24, H1 and H2 and quickly reaches 50-60 feet tall. Leaves are ferny, golden-green with silver undersides. Large clusters of bright orange-gold flowers bloom in early springtime. Wood is brittle and can be damaged by high winds; great as a tall screen or hedge. Can grow in poor, dense soils if it is not overwatered. Needs full sun to perform well. |
Grevillea rosmarinifolia (Rosemary Grevillea) This shrub grows well in zones 8, 9, 12-24 and reaches 6 feet tall and just as wide. Leaves are dark green with silver undersides, and look a bit like those of rosemary. Flower clusters are red and white, and bloom in fall and winter. Can be used as a clipped or informal hedge, and does well in heat and arid conditions. Needs full sun or partial shade. A dwarf variety is available that reaches 3 feet tall and 6 feet wide, with pink and cream flowers. |
Grevillea 'Ruby Clusters' This species takes the form of a shrub that reaches 6-10 feet tall and 9-15 feet wide, with dark green leaves. This species grows well in zones 9 and 14-24, and has deep red flowers that bloom throughout the year (most profusely in early springtime). Takes pruning well and needs full sun to partial shade to perform well. |
Grevillea sericea This shrub grows in zones 8, 9, and 14-24 and reaches 5-6 feet tall and wide. Flowers are lavender-pink and spidery, blooming heavily in late winter to early spring, and intermittently through the rest of the year. Easy to grow species that needs moderate water in hotter areas. Needs full sun to partial shade. Variety 'Collaroy Plateau' has deep rose-pink flowers on a more compact shrub. |
Grevillea 'Sylvia' This shrub is upright, and grows well in zones 16-24. Leaves are dark green on top, silver underneath, and flowers are raspberry-pink in color. Great cut flowers. Shear or cut back by a third after flowers fade to keep compact. This shrub is disease-resistant and tolerant of strong winds Needs full sun to light shade. |
Grevillea thelemanniana (Hummingbird Bush, Spider-Net Grevillea) This shrub is best in zones 9, 14-17 and 19-24 and has a graceful, open habit. Flowers are bright red, tipped with yellow and foliage is blue-green and soft to the touch. These shrubs prefer the climate of southern California over northern California, but can be grown in either place successfully. Needs full sun to partial shade. Varieties include 'Baby' (a dwarf selection with light green leaves reaching 6-8 inches tall and 3-4 feet wide, with a trailing habit), and 'Magic Lantern' (also called 'Gilded Dragon', with feathery greyish foliage to 2-3 feet tall and 4-6 feet wide). |
Grevillea victoriae This shrub grows well in zones 8, 9, and 14-24, and reaches about 6 feet or more tall and just as wide. Leaves are grey-green and flowers are orange-red during late winter and springtime. Provide with occasional summer water during dry spells to prevent bud drop. Can take sun but prefers part shade. Variety 'Murray Valley Queen' has profuse blooms and new growth that is covered with rust-colored hairs. |
Caring for and pruning Grevillea shrubs
Grow Grevillea in a sunny location in well-draining soil that is acidic to neutral and low in phosphates. They are considered easy-care plantings and do not need irrigating once established. Grevillea do not need to be fertilized, and will actually be damaged if the soil they are grown in is too rich in nutrients. Prune to shape; otherwise allow these shrubs to take on their natural habit. These shrubs can be grown in pots (either indoors in bright indirect light or outdoors), but will require some additional water in this situation. Provide protection from frosts, either by bringing a potted shrub indoors during cooler temperatures or by growing it in a protected spot next to a building or under an overhang.
Propagation
Grevillea can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:
Propagating Grevillea by Cutting
Propagating Grevillea by Seed
Propagating Grevillea by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming semi-hardwood branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.
Propagating Grevillea by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
- Harvest your seeds. The seed pods on Grevillea plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
- Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Problems and Pests
Grevillea shrubs and trees are generally pest- and disease-free, but can suffer from the following issues:
- Leaf Spot
- Cinnamon Fungus
- Honey Fungus
- Sooty Mold
- Scale
Gallery
Videos
Creating a Grevillea garden.
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All about Grevillea shrubs.
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Why to plant Grevillea in your yard.
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How to prune Grevillea plants.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 347 - 348, Grevillea
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