Growing Norfolk Island Hibiscus trees

WA Scene | December 31, 2022 | 0 Comments

How to grow Norfolk Island Hibiscus

Norfolk Island Hibiscus has the scientific name Lagunaria patersonii, but is known by a few different names including Pyramid tree, Cow Itch tree, Itchy Powder Tree, Queensland white oak, or sally wood. Norfolk Island Hibiscus is a neat looking, pyramidal shaped, evergreen tree with oval, leathery and hairy, sage-green leaves.

It has attractive pink to mauve flowers in spring and early summer. It is a plant that copes with exposure to salty sea winds, making it suitable for coastal areas.

Unfortunately, there are a few negatives to Norfolk Island Hibiscus. The tree’s seeds are poisonous if eaten and touching the plant might cause an allergic reaction or skin irritation. The seedpods contain very irritant hairs, and they are often referred to as the ‘itchy bomb tree’ as a result! Once the pods open the irritant hairs are released and blown on the wind, and often cause complaints. As a result some local government areas in Western Australia they are actively removing them from street verges.

If you have ever wondered how to grow Norfolk Island Hibiscus in Perth then look no further. Norfolk Island Hibiscus is a relatively easy tree to grow, however there are a few pros and cons to growing Norfolk Island Hibiscus. So it’s important to weigh these up prior to planting.

When to plant Norfolk Island Hibiscus trees:

Norfolk Island Hibiscus can be planted most months of the year, but it’s best to plant Norfolk Island Hibiscus during autumn. This will allow your plant time to establish roots before winter.

How much water do Norfolk Island Hibiscus trees need:

In the warmer parts of Australia recommend watering Norfolk Island Hibiscus deeply, one to two times a week, depending on weather conditions. It will perform best in well draining sandy coastal soil.

How big can Norfolk Island Hibiscus grow?

Norfolk Island Hibiscus trees can reach a height of 10 – 20m. Typically they have a width of 5 – 7m. It is suggested that Norfolk Island Hibiscus can grow to be over 50 years old.

How to prune Norfolk Island Hibiscus:

If you’re tree has pods on it I always recommend wearing gloves to avoid the itch. To control the shape of your tree it is best to prune suckers soon as they appear, make sure you use a very sharp pair of secateurs and cut as close to the trunk as possible. It is best to remove the suckers whilst the stems are still green. Allowing them to become woody removal will tend to encourage more suckers to grow. In general trees will send out suckers when they are under stress, this can occur as a tree reaches the end of life, change in conditions or pests or disease.

How fast do Norfolk Island Hibiscus grow:

Norfolk Island Hibiscus is a relatively slow growing tree, however it can eventually reach heights of approximately 20m. It is worth noting that it doesn’t flower until its 3rd year, and then prolifically every spring.

How to Norfolk Island Hibiscus at home:

If you are wondering how to plant a Norfolk Island Hibiscus tree in the garden then look no further. Growing Norfolk Island Hibiscus trees has become a bit less popular due to aforementioned itchy partials it releases from its seeds. However if this doesn’t put you off the flowers are quiet pretty.

Choose a spot in the garden that receives full sun or part shade. Enrich the well-drained soil with a high quality potting mix or soil improver. If your soil is clay based, add gypsum and fork in well.
Dig the planting hole twice as wide and to the same depth as the root-ball. Remove the hibiscus shrub from the pot, gently tease out the plants roots. Position in hole and backfill with soil, gently firming down the topsoil.
Form a raised or doughnut shaped ring of soil around the outer edge of the plant’s root zone. This helps keep water where it’s needed at the base of the tree. Always water in well after planting to settle the soil around the roots.
Mulch around the base with organic mulch like bark chips, keeping it away from the trunk to avoid the risk of any diseases.
Water deeply, one to two times a week, depending on weather conditions.
Feed every 6 – 8 weeks from spring to mid autumn with a Dynamic Lifter Soil Improver Plant Fertiliser and weekly with liquid plant food for flowers.

How to grow Norfolk Island Hibiscus trees in pots:

Growing Norfolk Island Hibiscus trees in pots is a great idea if you want to grow a relatively small Norfolk Island Hibiscus tree. I love to grow Norfolk Island Hibiscus trees in pots because it gives you the flexibility to move them around the yard, which can be handy if you have children or pets, and want to be able to move it to avoid contact with the pods.

Choose a pot at least 60cm wide.
Place the pot in a full sun to part shade and fill with quality potting mix.
Remove the hibiscus from the pot, gently tease out the roots.
Position in hole and backfill with potting mix, gently firm down the topsoil. Water in well.
Once planted, keep the plant well watered, but don’t let the water sit in a saucer at the base of the pot.
Feed weekly with liquid plant food for flowers during the spring.

How to propagate Norfolk Island Hibiscus trees:

The best time to propagate cotton hibiscus is in early spring or with temperature of 20-26C and better before the plant start to grow after the dormant period over winter.

The most common method of propagation is by seed. No special pretreatment is needed but care needs to be taken in removing seed from the pods so that the irritant hairs do not contact your skin.

Propagating Norfolk Island Hibiscus by cutting is also an option if you have a friend with a tree.

Choose stems that not going to bloom, cut a stem around 20-30cm in length. Plant your cuttings in a high quality potting mix with moist peat soil. Dipping the end in some root hormone will help the root growth. If you have a greenhouse then I recommend to use green house or a makeshift version plastic box with holes it. It should take 3-4 weeks for you cutting to start to grow. Once it has established fro 3-4 months you can then transplant to the desired location or to a new pot.

How to transplant a Norfolk Island Hibiscus:

Sometime your hibiscus will outgrow its current home. Many people look to move these trees due to their itchy nature. Whether it is for this reason or other reasons might lead you to want to transplant your hibiscus to a different spot.

Happily the process is pretty easy. First take a look and see how wide your plants canopy is. This is a good way to try to determine how big your root ball is. Carefully dig in and gently around the hibiscus plant in a circular fashion building off your root ball.

It is important to not try to lift your plant too early. Once it feels loose you’re ready to lift the plant up out of the ground. It is important to be careful to maintain as much of the root ball as possible.

Make sure your new hole is about the size of the root ball, it’s very important not to plant the plant too deeply, if it is too deep it can have troubles later on. It is also best to fill in with the soil that you dug out of the hole a lot of people want to fill in with new fresh soil but your plant will perform better with the existing soil which was around it. Firm the soil so you have good soil to root contact. Water it in and then your Norfolk Island Hibiscus is ready to thrive in its new location.

How to fertilise Norfolk Island Hibiscus trees:

Fertilise with hibiscus fertiliser or use a complete organic fertiliser. Look for one that’s fairly high in nitrogen and potassium and follow the directions on the bag.

When do Norfolk Island Hibiscus trees bloom:

A common question a lot of first time planters will ask is when does a Norfolk Island Hibiscus tree flower? The Norfolk Island Hibiscus, typically flowers prolifically during the springtime, however in some regions this will extended into early summer. The flowers are generally a pink to mauve but deeper coloured forms are in cultivation.

How to care for Norfolk Island Hibiscus:

As previously mentioned Norfolk Island Hibiscus is hardy and will grow across a wide variety of climates and soils, from tropical to temperate. There are really only three things required to care for Norfolk Island Hibiscus. First mulch and water well, second prune after flowering (noting this will stimulate fresh growth) and lastly fertilise in spring. Do these three things and your Norfolk Island Hibiscus should thrive.

Is Norfolk Island Hibiscus poisonous?

Yes, the mature trees will produce seedpods that contain orange seeds that have fine hairs that can be a skin irritant and are toxic to both humans and animals. It’s important to keep a close eye on children when playing near a tree, and if handling the pods it is recommended to wear gloves.