Grevillea olivacea – Australian Native Growing Guide

Introducing Grevillea olivacea

The Grevillea olivacea found its roots on the coasts of Western Australia. It’s a tough type of Grevillea and offers up some gorgeous flowers, starting in the winter and through to spring. Shades of red, orange and yellow will brighten up your garden. 

The name of the shrub makes reference to the leaf colour which is similar to the shade of green that you would find on an olive tree. Grevillea olivacea can grow to a height of 4 metres and is able to spread out up to 6 metres. The plant can live for around 10 years or more. 

Olive Grevillea’s flowers are much loved by birds that come and enjoy their sweetness. The flowers have a long blooming time and you might want to snip some of them from the garden to put in a lovely vase. 

If your garden is in need of a hedge or screen, Grevillea olivacea will provide the needed structure and beauty once it’s at least a metre in height. The shrub, if left to grow unaided, becomes round and bushy.

How to Grow Grevillea olivacea

The plant thrives particularly along the coast. When thinking about lighting needs, full sun is ideal but some shade will also be fine. The Grevillea olivacea needs good drainage when it comes to soil and slightly alkaline is fine. 

It’s able to adapt to many different types of soil. The shrub can also handle some drought and frost. True to its ability to be a good screening plant, the Grevillea olivacea can handle pruning and helps to add structure to the plant. 

Propagating Grevillea olivacea

How to Propagate Olive Grevillea from Seeds

This is the more lengthy route to go but if you have time and aren’t in a rush, you can allow the seed of the Grevillea olivacea to germinate on its own without needing to treat it beforehand. If you just leave the seed in soil, it will germinate within a year or two.

As the seasons progress and the soil becomes wet and dry in rotation, the seed coat cracks open and this then starts the germination process. 

Propagating Olive Grevillea from Cuttings

The best time to take a cutting is during the summer or at the start of autumn. The cutting should be semi ripe and aim for a length of around 10 centimetres. You can dip the Grevillea olivacea cutting into a rooting hormone and then plant it in a container with coarse sand.

Give it a little bit of water and be careful not to overwater. Your cuttings shouldn’t be directly in sunlight and the best way to maintain moisture levels is to mist them often. It can take around 6 months for new roots to sprout.

How to Care for Grevillea olivacea

Climate and temperature

The G. olivacea can handle both warm and cool temperate conditions and also a Mediterranean climate. It does particularly well in coastal areas and the ideal time to plant it would be during autumn or winter. 

Soil

G. olivacea likes a neutral or alkaline soil. It can adapt to many soil types including, sandy, loamy, and clay loam. Whichever soil you are growing it in, there should be good drainage. 

Watering

This shrub doesn’t need much water once it’s established, even in the summer. If you overwater G. olivacea, you could end up with root rot.

Pruning

G. olivacea likes pruning and this is the perfect way to keep it in shape. Depending on the needs of your garden, you can opt for a size and shape that works for you. 

What Fertiliser to Use

When you initially plant your G. olivacea, you can give it a slow release native fertiliser and then do an annual top up each year in spring.

Pests and Diseases to Look Out For

Scale

Scale is a type of sap sucking insect that likes to hang out on the stems, branches and leaves of plants. If you want to use an organic and environmentally friendly method to get rid of this pest, neem oil is a great way to go. 

Refer to our in-depth guide for neem oil to learn its types and how to use them the right way. 

If you are dealing with a very big infestation, you might need to use an insecticidal soap instead. Whichever treatment you are using, you can spray the entire plant and then wipe the leaves and parts of the plant affected with a paper towel. 

Grevillea olivacea Frequently Asked Questions

What is the conservation status of the Grevillea olivacea?

G. olivacea is listed as "Priority Four" by the Government of Western Australia Department of Biodiversity, Conservation and Attractions. This rating means that it is rare or near threatened.

Does the Grevillea olivacea cause allergies?

Grevilleas in general can cause skin irritation. If you find that you are sensitive, just cover up your skin when you’re busy with them in the garden. 

Can Grevillea olivacea handle wind?

G. olivacea has earned itself a reputation for being hardy and can indeed handle wind except in a very hot and desert-like climate. 

Do the roots of the Grevillea olivacea grow quite deep?

G. olivacea has a shallow root system. This means you don’t have to worry about any structural damage around your home or garden. 

Does Grevillea olivacea attract bees?

The delightful flowers of the G. olivacea make plenty of nectar and this attracts many native bees. 

Why does my Grevillea olivacea have yellow leaves?

If you notice the leaves of your G. olivacea turning yellow, it could be that the iron, phosphorus and pH levels of the soil are unbalanced. This is especially true if there is too much phosphorus in the soil. 

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Can't get enough of Grevilleas? Check out our main Grevillea growing guide.