Grevilleas are evergreen shrubs and trees in the Proteaceae family, known for their distinctive flowers, diverse foliage, and value to nectar-feeding wildlife. Native primarily to Australia, the genus includes nearly 400 accepted species.

Depending on the species or cultivar, Grevillea flowers may be red, pink, orange, yellow, cream, or white and often appear in distinctive spider-like or toothbrush-shaped clusters.

In this guide, you’ll discover popular Grevillea cultivars and learn how to grow and care for them, including their soil, sunlight, watering, fertilizing, pruning, and propagation needs.

Flower Lovers Want to Know

How many species of Grevillea are there?

The genus Grevillea includes nearly 400 accepted species. Most are native to Australia, although the genus also occurs naturally in New Guinea, New Caledonia, and parts of Malesia.

Are Grevilleas drought tolerant?

Many Grevilleas become reasonably drought tolerant once established, but water needs vary by species, climate, and soil conditions. Newly planted Grevilleas generally need regular watering while their root systems develop. Good drainage is important because persistently wet soil can cause problems.

What fertilizer is best for Grevilleas?

Grevilleas generally do not require heavy feeding. If fertilizer is needed, choose a low-phosphorus product formulated for Australian native or phosphorus-sensitive plants. Many members of the Proteaceae family are sensitive to excessive phosphorus.

Can Grevilleas tolerate frost?

It depends on the species or cultivar. Some Grevilleas tolerate significant frost, while others perform best in warm, frost-free climates. Check the cold tolerance of the particular Grevillea you plan to grow rather than applying one temperature range to the entire genus.

Are Grevilleas safe for pets?

Reliable veterinary information establishing the safety of Grevillea species for dogs and cats is limited. It is therefore best to prevent pets from chewing or ingesting the flowers, leaves, or other plant parts. Some Grevilleas can also cause contact dermatitis in sensitive people.

Can you eat Grevillea flowers?

Nectar from certain Grevillea species was traditionally used as a food source by some Aboriginal Australian peoples. However, this does not mean that all Grevillea species or ornamental cultivars are safe to consume. Avoid eating unidentified Grevilleas or assuming that garden cultivars are edible.

Why isn’t my Grevillea flowering?

Insufficient sunlight, unsuitable growing conditions, inappropriate fertilization, or pruning that removes developing flower growth can reduce flowering. Most Grevilleas bloom best in a sunny position with well-drained soil. Flowering patterns also vary considerably among species and cultivars.

Grevillea Flowers: Varieties, Growing & Care Guide

Grevilleas combine unusual flowers with an impressive range of growth habits, from spreading groundcovers to shrubs and trees. Understanding those differences is key to choosing the right Grevillea and providing the conditions it needs to thrive.

Quick Facts About Grevillea

Feature	Grevillea
Botanical name	Grevillea spp.
Family	Proteaceae
Plant type	Evergreen shrubs and trees
Native range	Primarily Australia; also parts of Malesia, New Guinea and New Caledonia
Flower colors	Red, pink, orange, yellow, cream, white and combinations
Light	Generally full sun
Soil	Well-drained; many prefer acidic conditions
Water	Regular while establishing; many become drought tolerant
Fertilizer	Low-phosphorus fertilizer if needed
Propagation	Seed for species; cuttings commonly used for cultivars
Wildlife value	Nectar source for birds and insects
Caution	Some Grevilleas may cause contact dermatitis

What Are Grevillea Flowers

Grevillea is a genus of flowering plants that belongs to the Proteaceae family. With nearly 400 accepted species, the genus includes plants ranging from spreading groundcovers to substantial trees. These plants are commonly known as spider flowers, silky oaks, and toothbrush plants.

• Botanical Classification – Grevilleas are predominantly shrubs, although some species develop into substantial trees. They have simple or compound leaves that are arranged alternately along the branchlets. The flowers are bisexual and usually have four tepals in a single whorl. They are zygomorphic and typically arranged in pairs along a sometimes branched raceme at the ends of branchlets.
• Geographical Distribution – Most Grevillea species are native to Australia, although the genus also occurs naturally in New Guinea, New Caledonia, and parts of Malesia. They are adapted to a wide range of climates and soil types, from tropical rainforests to arid deserts. Some species are also cultivated as ornamental plants in other parts of the world.

Growing Grevillea

Planting Guidelines

Choose a planting location with good drainage and enough space for the Grevillea’s mature size. Growth habits vary considerably across the genus, from spreading groundcovers and compact shrubs to large shrubs and trees, so check the expected height and spread of your particular species or cultivar before planting.

Plant when conditions are mild enough to allow the roots to establish without severe heat, drought, or frost stress. The best planting season will therefore depend on your local climate.

Dig a hole approximately twice as wide as the root ball but no deeper than the root system. Position the plant at approximately the same soil level at which it was growing in its container, backfill gently, and water thoroughly after planting.

Keep the surrounding soil well drained and avoid burying the base of the stem. Space multiple Grevilleas according to their expected mature width rather than using a single spacing recommendation for the entire genus.

Soil Requirements

Grevilleas generally grow best in well-drained soil, and many species prefer slightly acidic conditions. Good drainage is particularly important, as prolonged waterlogging can contribute to root problems.

Depending on the species, Grevilleas can grow in sandy, loamy, gravelly, or other relatively free-draining soils. If your soil is heavy or drains poorly, improving drainage or planting in a raised area may provide better growing conditions.

Avoid heavily enriching the soil or routinely applying high-phosphorus fertilizers. As members of the Proteaceae family, many Grevilleas are adapted to relatively nutrient-poor soils and can be sensitive to excessive phosphorus.

Water

Water newly planted Grevilleas regularly while their root systems establish, allowing excess water to drain freely. Once established, many species and cultivars are reasonably drought tolerant, although supplemental watering may be needed during prolonged hot or dry periods. Avoid keeping the root zone continuously saturated.

Sunlight and Temperature Needs

Most Grevilleas grow and flower best in full sun, although some species and cultivars can tolerate light or partial shade. Providing plenty of sunlight generally encourages denser growth and more abundant flowering.

Temperature tolerance varies considerably among Grevillea species and cultivars. Some are well adapted to cool conditions and can tolerate significant frost, while others perform best in warm, frost-free or subtropical climates.

Choose a Grevillea suited to your local climate rather than relying on a single temperature range for the entire genus. In colder regions, frost-tender varieties may need a protected location or container culture that allows them to be sheltered during winter.

Varieties of Grevillea

With nearly 400 accepted species and numerous horticultural hybrids and cultivars, Grevilleas vary considerably in size, flower color, growth habit, and flowering season. Here are several distinctive cultivars to consider.

Popular Cultivars

1. Grevillea ‘Robyn Gordon’ – A bushy shrub growing to about 1.5 m (5 ft) tall and wide. It produces distinctive deep red flowers and can bloom throughout much of the year in suitable climates. Its flowers are also attractive to nectar-feeding birds.
2. Grevillea ‘Moonlight’ – A large, spreading shrub that can reach about 5 m (16 ft) tall and 4 m (13 ft) wide. Its large flower clusters are bright cream to yellow and may appear over much of the year.
3. Grevillea ‘Honey Gem’ – A vigorous shrub reaching approximately 4 m (13 ft) tall and 3 m (10 ft) wide. It produces large golden-yellow flower clusters during much of the year, often with a particularly strong display in late winter and spring.

More Grevillea Cultivars to Consider

1. Grevillea ‘Poorinda Royal Mantle’ – A vigorous, spreading groundcover that can reach 3 m (10 ft) or more across. Its bright red, toothbrush-shaped flower clusters contrast with its broad foliage, making it useful for covering banks and other open areas.
2. Grevillea ‘Pink Surprise’ – A tall, open shrub producing large pink flower clusters with contrasting cream styles. It can reach around 4 m (13 ft) tall and flowers over an extended period. This cultivar is better suited to warmer or protected locations than frost-prone sites.
3. Grevillea ‘Superb’ – A bushy shrub growing to about 1.5 m (5 ft) tall and 2 m (6.5 ft) wide. It produces large apricot-orange flower clusters throughout much of the year and performs best in a sunny, well-drained position. It can also tolerate moderate frost once established.

Grevillea Care

Grevillea care varies somewhat by species and cultivar, but good drainage, appropriate fertilization, and regular light pruning can help many garden varieties remain healthy and vigorous.

Pruning

Grevilleas generally respond well to light, regular pruning, which encourages branching and helps maintain a dense shape. Pruning requirements vary by species and cultivar, so avoid cutting heavily into old, leafless wood unless the particular Grevillea is known to tolerate hard pruning. When in doubt, leave healthy green foliage on each branch.

Fertilization and Nutrition

Grevilleas generally do not need heavy feeding. Because they belong to the Proteaceae family, many are sensitive to excessive phosphorus.

If fertilizer is needed, choose a low-phosphorus fertilizer formulated for Australian native plants or phosphorus-sensitive plants and follow the label directions carefully. Avoid routinely applying high-phosphorus fertilizers around Grevilleas.

Propagating Grevillea

Grevilleas can be propagated from seed or cuttings, although the best method depends on whether you are growing a species or a named cultivar.

Growing from Seed

Seed propagation is commonly used for Grevillea species. Because seedlings can vary genetically from their parent plants, this method is less suitable when you want to reproduce the exact characteristics of a particular cultivar.

Sow fresh seed in a well-draining propagation mix and keep it lightly moist rather than waterlogged while germination occurs.

Propagating from Cuttings

Cuttings are generally the better choice for named Grevillea cultivars because vegetative propagation produces plants with the same characteristics as the parent plant. Seedlings from hybrids and cultivars such as those in the ‘Robyn Gordon’ group may not come true to type.

Take healthy young stem cuttings and place them in a free-draining propagation medium. Keep the medium lightly moist and provide a protected environment while roots develop. Once well rooted, young plants can gradually be acclimated to their normal growing conditions.

Pest and Disease Management

Grevilleas are generally not affected by serious pest problems when grown in suitable conditions, but several pests can occasionally cause damage.

• Scale insects: These sap-feeding pests may appear as small bumps on stems and leaves. Heavy infestations can weaken growth and produce sticky honeydew.
• Sooty mould: This dark fungal growth can develop on honeydew produced by scale and other sap-feeding insects. Controlling the insect responsible for the honeydew usually addresses the underlying problem.
• Caterpillars: Some caterpillars feed on Grevillea foliage and may cause noticeable leaf damage. Minor feeding can often be tolerated without treatment.
• Borers: Wood-boring insects can damage stems and branches, particularly on stressed plants. Look for declining branches, holes in stems, or other signs of boring activity.

Root problems can also occur when Grevilleas are grown in poorly drained or persistently wet soil. Providing good drainage and avoiding unnecessary overwatering can help reduce the risk.

Check plants regularly and identify the cause of damage before applying a treatment. Minor pest activity may not require intervention, particularly when it does not threaten the overall health of the plant.

Skin Irritation

The foliage of some Grevilleas can cause contact dermatitis in sensitive people. Cultivars in the ‘Robyn Gordon’ group are among those commonly associated with reactions. Wearing gloves and long sleeves while pruning can help reduce skin contact.

Landscaping with Grevillea

Grevilleas range from spreading groundcovers to large shrubs and trees, making them useful in many landscape settings. Choose a species or cultivar whose mature size and growth habit suit the available space.

Design Ideas

• Hedges and screens: Dense, shrubby Grevilleas can be planted as informal hedges or privacy screens. Regular light pruning can help maintain a fuller shape.
• Containers: Smaller Grevilleas can be grown in containers with excellent drainage. Choose a cultivar suited to container culture and avoid keeping the potting mix continuously wet.
• Mixed borders: Shrubby Grevilleas can provide colorful flowers, distinctive foliage, and structural interest in mixed beds and borders.
• Groundcovers and rock gardens: Low-growing and spreading Grevilleas work well on slopes, in rock gardens, and as groundcovers where drainage is good.

Companion Plants

When choosing companion plants for Grevilleas, look for species with similar preferences for sunny conditions, good drainage, and relatively low water and fertilizer needs.

• Kangaroo paw (Anigozanthos spp.): Its upright, colorful flowers contrast well with the foliage and spreading forms of many Grevilleas.
• Lomandra (Lomandra spp.): Tough, grass-like foliage provides texture and works well in low-maintenance Australian-inspired plantings.
• Blue fescue (Festuca glauca): Compact blue-gray foliage can provide contrast along borders and in rock gardens.
• Succulents: Drought-tolerant succulents can work alongside Grevilleas in sunny, well-drained sites, provided their soil and watering requirements are compatible.

Avoid pairing Grevilleas with plants that require consistently wet soil or frequent applications of high-phosphorus fertilizer.

Grevillea Uses

Grevilleas are valued primarily as ornamental plants, but their nectar-rich flowers can also provide an important food source for wildlife.

Ecological Benefits

Grevillea flowers provide nectar for birds and insects. In Australia, honeyeaters are frequent visitors to many Grevillea species and can contribute to pollination as they move between flowers.

Including suitable Grevilleas in a garden can therefore provide both ornamental value and a nectar source for visiting wildlife.

Traditional Uses

Nectar from certain Grevillea species was traditionally used as a food source by some Aboriginal Australian peoples. However, this traditional use should not be interpreted to mean that all Grevillea species, cultivars, flowers, or other plant parts are safe to eat.

Because the genus contains hundreds of species and reliable food-safety information is not available for every Grevillea, gardeners should not consume unidentified plants or assume ornamental cultivars are edible.

Ornamental Uses

Grevilleas are widely grown for their distinctive flowers, attractive foliage, and diverse growth habits. Depending on the species or cultivar, they can be used as specimen plants, groundcovers, flowering shrubs, hedges, screens, or small landscape trees.

Selecting a Grevillea suited to the local climate, soil, and available space is important because mature size and growing requirements vary considerably across the genus.

Final Sprouts of Wisdom

Grevilleas offer an impressive range of flower forms, foliage, and growth habits, from spreading groundcovers to shrubs and trees. Choosing a species or cultivar suited to your climate and providing plenty of light and well-drained soil are among the most important steps toward successful cultivation.

Once established, many Grevilleas require relatively little supplemental water or fertilizer. Avoid excessive phosphorus, prune according to the needs of the particular variety, and provide good drainage to keep these distinctive plants healthy and flowering.

Similar Posts

 

Discover the Rarest and Most Unusual Succulents in the World

 

all images from Canva