Acacia cognata or acacia limelight is one of the best-selling wattle cultivars, and it’s easy to see why. With incredible, soft-swaying vegetation, the acacia limelight adds a wonderful focal point in gardens, entryways and around fences.
Used often in tropical and traditional Asian gardens, this Aussie native grows well in pots and garden beds, accustoming quickly to poorer soil conditions, considering growing your own Acacia cognata at home?
Here is everything you need to know to cultivate, grow and care for acacia cognata.
What Are Wattle Trees?
Wattles are incredibly popular, semi-deciduous trees that can be found almost anywhere in Australia. With their incredible ability to withstand harsh environments, Wattles or Acacia’s are the largest genus of flora across Australia.
These hardy inhabitants can thrive despite harsh winds, droughts, bushfires, and floods. Plus, with dense, evergreen foliage, they’re fantastic feature plants too.
Many say that their resilience is a direct representation of the spirit of the Australian people. These hardy inhabitants can thrive despite harsh winds, droughts, bushfires, and floods.
Plus, with dense, evergreen foliage, they’re fantastic feature plants too. Many say that their resilience is a direct representation of the spirit of the Australian people.
The acacia cognata is a common, dwarf variety of wattle, making it an ideal option for smaller gardens or compact spaces. Also known as the Bower or River Wattle, this lime green shrub is a great choice for garden beds, borders, greenhouses and walls.
The most popular acacia limelight varieties include:
- The Mini-Cog. A very small cultivar, great for indoors.
- The Bower Beauty. A colourful cultivar offering an attractive bronze and orange growth at the tips.
- Lime Magik. A weeping, willow-style cultivar growing only about 1 metre in height.
- River Cascade. Stunning as a landscaping feature and suitable for hedge growing.
- Green Mist. Beautiful and bright, ideal as a focal point in gardens.
How to Grow Acacia Cognata
As with most acacia trees, the acacia limelight enjoys a fair amount of sunlight throughout the day, so it’s important to pick the right spot when beginning the growing journey. Full sun or partly shaded will be suitable.
In the wild, most acacia plants grow freely, even in poor soil conditions. However, when growing at home, you will want to ensure you’re growing acacia cognata in a plentiful supply of sandy, loamy, well-draining soil. Usually, a low-phosphate potting mix is recommended.
While they are very hardy plants, you will want to ensure your acacia limelight is protected from the elements when still establishing themselves.
Propagating Acacia Limelight
Propagation through cuttings is the easiest and most effective. These cuttings should be taken in the spring or in early autumn, as colder conditions may affect your acacia limelight’s ability to take root.
In general, cuttings taken during warmer conditions have an 80% success rate. More so, you can take multiple cuttings at once to propagate plenty of smaller plants.
- Remove a healthy branch close to the tip, approximately 10 cm in length.
- Strip the lower half of the foliage and cut it down to about 5 cm in length.
- Stick the cut edge into a seeding tray with a rich potting mix to root.
For rooting, you will want to use denser potting soil. A mixture of 90% perlite and 10% peat moss is recommended.
Rooting will take as long as 2 to 3 months. Ensure you are watering your cuttings regularly and giving them bright, indirect sunlight throughout the day.
Repotting Acacia Limelight Once It Takes Root
It’s important to wait long enough before re-potting your cuttings as they have incredibly sensitive roots. Remove your cuttings carefully from the seeding tray and gently plant them into a pot.
As acacia cognata plants grow naturally in poor soil conditions, you can use a native mix of organic compounds for your soil.
Try to keep your pot in a spot that is warm and gets plenty of indirect sunlight. In the early growing stages, cuttings can be negatively affected by too much direct sunlight. However, too little light will also prevent growth.
It is recommended to leave your growing acacia cognata in the pot for at least 3 months before transplanting it into a bigger pot or garden bed.
Caring for Acacia Cognata
Acacia cognata care really doesn’t require much once the plant is established. This particular cultivar will maintain its exquisite lime green colour, even in times of drought.
So, when it comes to watering, you won’t have to worry much. Should you experience a season with particularly low rainfall, consider supplementing with some additional water once a week. Otherwise, your acacia limelight will get all the water it needs from the natural rainfall.
It’s also always a good idea to support your cognata with some additional fertiliser during springtime, which will help boost growth. Any native fertiliser will do the trick.
Pruning Acacia Cognata
Pruning will be the only laborious aspect of your acacia cognata care. Pruning can be done to promote plant health, vigorous growth and maintain shape and size.
How much you will want to prune your cognata will depend on where you’re growing it. For instance, for an acacia cognata hedge, you will want to prune more regularly to ensure the right shape and size.
In general, you can cut back as much as half of your acacia cognata hedge using a sterilized pair of garden shears.
Pests, Problems & Diseases
This cultivar is relatively pest and disease-free, meaning you won’t have many issues throughout your growing journey.
The only issues some growers have experienced is with red spider mites and mealybugs. Luckily these are easily treated with an organic, horticultural spray or neem oil.
Worms, caterpillars and borers may also take favour to your acacia limelight. The most common pest you may encounter is the incredibly invasive shot hole borer. You will need to undertake immediate reactive treatment, as these garden pests tend to spread.
Common Wattle Problems
While it’s not specific to the acacia limelight, many wattle trees are highly susceptible to root rot or Phytophthora cinnamomi. This highly intrusive rot attacks the tissues of the plant, causing it to wilt and eventually collapse.
Unfortunately, there isn’t much you can do to treat this kind of rot and it’s best to remove an infected plant before it can infect the rest of your garden. Be sure to sterilise and clean any materials used to remove the tree in order to avoid cross-contamination.
More on our Acacia Plant Series
Acacia Cognata Frequently Asked Questions
Why is Acacia cognata called ‘Limelight’?
Acacia cognata gets its common name from the frosted, lime green glow that passes through its delicate foliage in the afternoon. While its foliage is typically grassy-green in daylight, direct sun passing through the thin leaves highlights the vivid and plentiful chlorophyll in the leaves, creating a stunning lime green glow.
Is Acacia cognata native to Australia?
Acacia cognata is native to Australia, specifically south-eastern Australian, where this wattle can be found growing in abundance in the wild. The seeds self-sow fairly easily on southern soils, and can germinate readily beneath the weeping branches of their parents.
What can I plant with Acacia cognata?
Acacias can be grown as shrubs or small trees, depending on your location, but as a fairly short-lived plant, they benefit from other shrubs, small trees, or tall perennials around their base.
In moist soils, planting hungry plants around their base helps to manage soil conditions, and create a slightly drier environment for them. Try growing Azaleas, Hydrangeas, or Camellias alongside your Acacia cognata.
Where is the best place to plant an Acacia tree?
Acacia trees are best in well-drained soil, in full sun but some protection from the wind. The main problem with growing Acacias is their brittle stems, which are easily damaged by high winds, so with their relatively non-invasive roots, it’s worth planting them near the house, or with some structural protection to help them live longer.
What is the lifespan of Acacia cognata?
Acacia cognatas tend to live for about 30 years. They are incredibly fast growing, and all of that energy simply exhausts the tree in time, putting pressure on their brittle limbs, and exhausting their roots.
With good wind protection, and light irrigation on well-drained soil, some Acacias have been known to live much longer.
Is Acacia cognata fast growing?
Acacia cognata is fast growing, and can put on around 50cm-1m of new growth each year, reaching its full height of 4m in just eight years. Acacias, and Acacia cognata are particularly useful when speeding up the establishment of new gardens.
How deep do Acacia cognata roots go?
Acacia cognata roots can reach as far down as 15m into the soil, but rarely do in cultivation thanks to compacted garden soil, and poorer drainage. However, as fast growing, short-lived trees, they do not pose any real threat to structures and their roots will usually just grow around, rather than through their surroundings.
Can Acacia cognata grow in shade?
All Acacias, Acacia cognata included, prefer to grow in full sun, but they can be cultivated in surprisingly deep shade. In nature, they germinate under the shade of their parents, so are well adapted to these conditions, but the stronger seedlings out-compete their parents, and tend to grow through in search of full sun in the end.
What are the benefits of planting an Acacia tree?
Planting Acacia trees help to nourish the soil by fixing nitrogen at their roots, and pulling nutrients in from far and wide. Planting an Acacia in a garden with poor soil helps to improve the soil for new planting, and eventually, your planting will outlive the tree but remain with the legacy of improved soil.
Is Acacia cognata messy?
Acacia cognata is a fairly clean tree in terms of leaf-drop, but the constant dropping of seed pods can be a problem, requiring regular sweeping to avoid constantly Acacia saplings from germinating in your lawns and borders.
Can Acacia cognata survive winter?
There are some species of Acacia that can survive a light frost, Acacia cognata included. Prolonged frost and temperatures below 0°C will kill Acacia cognata though, so protect them from frosts that last longer than a single night.
Do ticks live in Acacia cognata?
The wattle tick scale is a scale insect, rather than a tick, but it does closely resemble common ticks. They are not harmful to humans, but can badly affect Acacia cognata if infestations get out of control.
Wrapping Up Our Acacia Cognata Limelight Growing Guide
If your goal is to grow lush, ornamental foliage, then the acacia cognata is the way to go. Take care when establishing your cutting, ensuring you give it enough time to root and when replanting is very gentle with those roots.
Once established, your acacia cognata hedge or shrub will just need plenty of sun and some occasional watering. Keep an eye on your soil to make sure it’s always draining adequately.
Follow these tips, and you’ll have plenty of beautifully growing acacia cognata trees all around your garden.