Grevillea Preissii | Growing and Care Guide Australia

Grevillea Preissii Features

Part of the Proteaceae family, grevilleas are a prized range of Australian native shrubs and smaller growing trees endemic to Western Australia. 

Unlike other grevillea species, which generally produce loose, spreading flowers, the grevillea seaspray are more tightly bunched flowers which form in large, brightly coloured clusters along with the grey-green foliage. 

Named after the famed botanical collector, J A Ludwig Preiss, it is a great choice as a ground cover or care-free feature plant whose rich nectar will bring a beautiful array of nectar-feeding birds and insects to your garden. 

Dwarf varieties of the cultivar also exist, which are perfect for growing in compact spaces and containers. 

Other common names for the grevillea preissii include:

• Spider Net Grevillea
• Toothbrush Grevillea
• Grevillea Gilt Dragon

How to Grow Grevillea Seaspray

The seaspray is best suited for growth in coastal regions and areas which experience a hot and dry summer climate. They’re not too fond of the cold, so the warmer, the better. Avoid growing your seaspray in overly shaded and damp areas of your garden, as it’s usually a recipe for disaster. 

Pick a spot in your garden that gets lots of sun for the best growth. Although they can tolerate semi-shaded areas, exposure to full sun will encourage greater growth and more flowers. 

When it comes to soil conditions, grevilleas can tolerate most kinds of soils, provided they drain well. You can grow your seaspray in sandy, rocky, limestone and loam soils. If trying to grow your grevillea preissii seaspray in a pot, it is advisable to place a layer of loose rocks at the bottom of the container to help the soil drain. 

Propagating Grevillea Seaspray

Grevilleas can be propagated by seed or by semi-hardwood cutting. Although, propagating by seed is often the easiest and cheapest option as they’re readily available from the fruits which form after flowering. 

Growing Grevillea Preissii from Seed

Seeds are best sown during spring and summer as they don’t often germinate when the conditions are too cold. Ideal temperatures for germination are between 18°C and 22°C. Seeds do require some pre-treatment to guarantee success.

• Before sowing, gently knick the seeds with a knife or sharp blade. This will help encourage germination. 
• Soak seeds in warm water overnight; this will soften the outer layer and further increase the chance of germination. 
• Once soaked, prepare a seedling tray or small pot with a rich seeding mixture. 
• Place the seed on the surface of the soil and cover lightly with some soil. 
• Water well right after sowing. Then, keep the soil consistently moist and warm to encourage germination. 
• Germination will occur between 21 to 60 days.

As with other native species, sometimes seeds can be stubborn and wait for the ideal time to germinate. As such, it’s best to be patient with seeds should you not see results. 

Grevillea Seaspray Propagation from Cutting

Cutting can be slow to strike, but once they do, they tend to establish themselves pretty quickly. Cuttings should only be taken from healthy, thriving plants. Always carefully inspect cutting for signs of disease, pests or damage. 

• Remove a semi-hardwood cutting around 8 to 10 centimetres in length. 
• Prepare a small container or pot with a porous potting mixture. 
• For optimal results, dip the end of your cutting into a rooting hormone which will promote root growth. 
• Plant the cutting directly into the soil. Keep the soil moist, and you're cutting in a sunny spot. 
• Replant into a larger or into the ground once you can see new growth appear. 

Planting Grevillea Preissii Seaspray

Once your grevillea is ready to be planted, it’s time to pick your spot and prepare it. Although these plants aren’t overly picky, it’s always a good idea to mix in some organic matter into extremely poor soils.

In areas with poorly draining soils, mixing in some coarse organic material can help to improve drainage. 

To plant, here is what you’ll need to do:

• Find a sunny spot and dig a hole twice the size of the rootball. While not necessary, a granular, slow-release fertiliser can be dug into the soil. 
• Remove the plant from its original pot and gently shake to loosen any of the leftover potting soil. 
• Place the root ball into the hole and backfill with the rest of the soil. 
• Press down the soil, which will help to stabilise the trunk and keep your plant in place.

In areas that experience a lot of wind, it may be necessary to stake younger plants until the roots have established themselves. Keep plants well-watered right after planting. 

Grevillea Seaspray Care Tips

Grevilleas are known to be some of the toughest endemic plants, which means they have a relatively fuss-free maintenance routine. They’re salt-tolerant, drought-tolerant and won’t need much pruning or fertilising. 

In the first few months of growth, while plants are establishing themselves, they will require more water than usual. During this period, you can water them as much as once per week.

It’s important to note that the seaspray doesn’t like wet feet, so avoid watering if the soil is already wet. Allow the soil to dry out completely in between watering. In rainy or cold weather, avoid supplementary watering altogether. 

No additional compost or fertiliser needs to be added. However, if your plants are looking drab or lacking growth, a slow-release, annual fertiliser can be added annually to support your plants. Be sure to pick a native fertiliser or a seaweed fertiliser for the best results. 

See our Australian garden fertilisers guide so you can pick the right fertilisers for your plants. 

Pruning Grevillea Preissii

While pruning isn’t often needed with grevilleas, it can be done to maintain the size and shape of your plants. Pruning should be done after flowering for the best results.

Delay pruning, however, if you’re hoping to grab yourself some seeds. Fruits only develop shortly after flowering. Be sure to sterilise garden shears before and after pruning to avoid your plants coming in contact with diseases. 

If growing your grevillea for smaller ground cover, more regular pruning may be required to control growth. (Get the best pruning shears for the job.)

Common Seaspray Pest, Problems and Diseases

Typically grevilleas don’t have any issues. They’re not particularly susceptible to pests and are relatively resistant to the same issues other garden plants may develop. 

The most common issue growers may experience is due to overwatering. Leaving your grevillea with wet feet will quickly lead to a root rot issue. Unless this issue is tackled quickly, by cutting back on watering or replanting, it can lead to the death of your plant. 

Keep a careful eye on your soil, and always wait until the soil dries out before watering again. 

Another challenge that these plants pose is that they’re at risk of becoming infected with  ‘dieback’ (a soil-borne disease caused by the organism Phytophthora cinnamomi). Do your best to protect your plants from dieback obtaining plants and seeds from registered native nurseries and avoiding taking cuttings from wild-growing plants. 

Should you have any plants in your garden which have been infected by dieback, remove them immediately taking care not to touch any other plants in your garden thereafter. These infected plants need to be destroyed by means of fire immediately to prevent further spread.

Seaspray Landscaping Ideas

Adaptable and easy to grow, you can grow your grevillea seaspray almost anywhere. However, if you’re not sure where to start, here are a few great tips to get you started:

• Grow your grevillea seaspray alongside other pure, evergreen plants. The grey-green foliage of the seaspray can compliment it beautifully. 
• As they’re happy to grow in loose soils, think about planting your seaspray as part of a rock garden or on rocky slopes. 
• Grevillea seaspray can also be grown as a low-growing, beautifully flowering hedge. While their growth is not overly dense, they’re great to border patios, flowerbeds, and even pools. 

Are you thinking of adding some other grevilleas to your garden landscape? Here is our main Grevillea guide.