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. 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 the garden. Take care when planting these plants in your yard, as the leaves of some species can cause skin irritations and rashes and ingestion of plant parts can cause a toxic reaction.

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, Alpine Grevillea, Cat's Claws, Downy Grevillea, Quoll's Claws)
This species of shrub varies in size and form, and grows well in USDA hardiness zones 8-10 or Sunset 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 asplenifolia (Fern Leaf Grevillea, Fern Leaved Grevillea, Asplenium Grevillea)
Best in USDA hardiness zones 9a-11b or Sunset growing zones 15-24, this shrub reaches between 9 and 15 feet tall and 9 to 20 feet wide, with long, linear green leaves. Flowers are deep red, blooming in clusters from late winter through springtime. Great as a screening plant, and can take full sun but prefers partial shade.

Grevillea australis (Alpine Grevillea, Southern Grevillea)
This shrub does well in USDA hardiness zones 7a-10b or Sunset growing 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 (Bank's Grevillea, Byfield Waratah, Red Flowered Silky Oak, Dwarf Silky Oak, Kāhili Flower)
Best in USDA hardiness zones 9b-11 or Sunset growing 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. This species is considered invasive in Madagascar and Hawai'i.

Grevillea spp. Hybrids (Hybrid Grevillea)
This group of Grevillea plants vary in size, form, foliage, and flower colors, and were generally bred for garden cultivation.

'Allyn Radiance'
To a foot tall and 5 feet wide.

'Apricot Charm'
To 5 feet tall and 6.5 feet wide.

'Apricot Glow'
To 6.5-10 feet tall.

'Billy Bonkers'
To about 3-5 feet tall and 6-9 feet wide.

'Birdsong'
To 6.5 feet tall.

'Bon Accord'
To 13 feet tall and wide.

'Bonfire'
To 4-6 feet tall, 6-8 feet wide with rose-red blooms.

'Bonnie Prince Charlie'
To 3 feet tall and 4 feet wide. Bicolor red and yellow blooms.

'Boongala Spinebill'
3-5 feet tall and 15 feet wide. Red flowers year-round.

'Border Red'
4 feet tall and wide.

'Bronze Rambler'
Ferny foliage is bronze when new. 1 ft. tall, 10 ft. across

'Calounda Gem'
Honey-colored flowers on a 6.5-16 foot tall shrub.

'Canberra Gem'
To 8 feet tall and 12 feet wide; open habit and red flowers.

'Carpet Layer'
Dense groundcover with pink flowers.

'Carpet Queen'
With apricot-colored flowers on a prostrate shrub.

'Clearview David'
To 10 feet tall and 13 feet wide.

'Coastal Dawn'
To 13 feet tall and 6.5 feet wide.

'Coastal Gem'
To 1 foot tall and 4-5 feet wide; good groundcover.

'Coconut Ice'
To 5-6.5 feet tall with pink flowers.

'Cooroora Cascade'
With cascading branches and yellow flowers.

'Copper Crest'
With copper new foliage, good groundcover.

'Desert Flame'
Compact with yellow and pink flower inflorescences.

'Dorothy Gordon'
With mauve blooms and grey-green foliage.

'Evelyn's Coronet'
6.5 feet tall and wide, with compact pink flowers.

'Fanfare'
Low, to a foot tall and 10-15 feet wide. Deep red flowers.

'Firesprite'
To 9-12 feet tall and 15 feet wide.

Grevillea 'Firesprite'
This species does well in zones 8, 9, 14-17 and 21-24 and reaches 9-12 feet tall and 6-8 feet wide. Leaves are bright green and divided, and flowers are yellow and red, blooming in spring and summer. Needs full sun to perform well.

Grevillea 'Ivanhoe'
Best in zones 14-24 with a dense, spreading habit reaching 6-15 feet tall and 9-15 feet wide with finely divided leaves. Flowers are pink-red and bloom in clusters at branch tips from late winter through summertime. Needs full sun or light shade.

Grevillea lanigera (Wooly Grevillea, Rusty Spider-Flower)
This shrub is best in USDA hardiness zones 8-11 or Sunset growing 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 USDA hardiness zones 8-10 or Sunset growing zones 15-24. It produces 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 'Long John'
To 8-10 feet tall and 12-15 feet wide, with long, needle-like leaves. Best in zones 15-24, and blooms in early spring with pink and red flowers. Easy to grow and useful as a screening plant; best in full sun exposure.

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 'Red Hooks'
This shrub or small tree reaches 12 feet tall and 18 feet wide, with fine-cut foliage. It is best in zones 16-24 and needs full sun to light shade. Prune hard when young to encourage bushy growth. Flowers are coral-red, blooming from late winter through late springtime.

Grevillea robusta (Silky Oak, Southern Silky Oak, Australian Silver Oak, Silver Oak)
This tree does well in USDA hardiness zones 9b-11 or Sunset growing 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. This species is considered invasive in Hawaii, South Africa, certain areas of Australia, New Zealand, Jamaica, French Polynesia, and Florida (United States).

Grevillea 'Robyn Gordon'
This shrub does well in zones 16-24 and reaches 4-6 feet tall and wide. Leaves are light green and divided, and flowers are bright red, forming in dangling clusters through most of the year. Needs full sun.

Grevillea rosmarinifolia (Rosemary Grevillea, Coastal Gem Spider Flower)
This shrub grows well in USDA hardiness zones 8-11 or Sunset growing 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. This species is considered invasive in south Australia.

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 'Scarlet Sprite'
Reaches 3-5 feet tall and about as wide, and grows well in zones 8, 9, and 12-24. Flowers are bright red and bloom almost year-round. Can be sheared into a low hedge; needs full sun to partial shade.

Grevillea sericea (Pink Spider Flower, Silky Grevillea)
This shrub grows in USDA hardiness zones 9-10 or Sunset growing 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 'Superb'
This shrub grows well in zones 16-24 and reaches 3-4 feet tall and 6 feet wide, with apricot colored flowers. Best in full sun.

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 USDA hardiness zones 9a-11b or Sunset growing 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 (Royal Grevillea, Mountain Grevillea)
This shrub grows well in USDA hardiness zones 7-10 or Sunset growing 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.

Grevillea 'White Wings'
This shrub is best in zones 15-24 and reaches 6-9 feet tall and 10-15 feet wide with finely divided bright green leaves. In springtime, fragrant white blooms appear in numbers. Great as a bank or slope planting for erosion control, and takes full sun to partial shade.

Caring for Grevillea

Take care when planting these plants in your yard, as the leaves of some species can cause skin irritations and rashes and ingestion of plant parts can cause a toxic reaction. Grow Grevillea in a sunny location in well-draining soil that is acidic to neutral and low in phosphates. Provide shelter from frost and high winds. Grevillea prefer well-draining, somewhat poor soil that has a pH of between 5.5 and 6.5. If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention.

Water new plantings regularly as they establish a strong root system in their new home. At maturity, these shrubs are considered to be drought-tolerant, able to get by for much of the year on rainwater alone, with supplemental irrigations during extended periods of drought. As a general rule of thumb, water deeply when the top 2-3 inches of soil feels dry to the touch. Avoid overwatering, which can lead to root rot issues. These trees and shrubs are well-adapted to poor soils, and do not generally require fertilization. Grevillea can be pruned as needed to maintain shape and size, and to remove dead, dying, damaged, crossing or diseased branches. Prune to shape; otherwise allow these shrubs to take their natural form. These shrubs and trees have a typical lifespan of between 10 and 20 years in the landscape.

Caring for Grevillea in Containers
Grevillea shrubs are wonderful in the ground, but can also be grown in containers. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a well-draining potting mix amended with organic material and perlite, and top with a layer of mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Grevillea plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

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

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. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
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. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
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.

Grevillea seed pods are left behind after flowers have faded.

Grevillea seeds are produced in pairs within seed pods, and are often winged.

Problems and Pests

Certain Grevillea species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Grevillea shrubs and trees are generally pest- and disease-free, but can suffer from the following issues: