Best Erosion Control Plants in Brisbane: A Guide for Landscape Architects

Erosion is a significant issue in Brisbane, particularly with seasonal heavy rainfall and dry periods with significant heat. Landscape architects play a crucial role in mitigating the effects of erosion, designing landscapes that are not only beautiful but also contribute to the stability of the land.

One of the most effective tools at our disposal in this fight against erosion is the strategic use of plants. Through their root systems and ground cover, plants can significantly reduce the rate of erosion, stabilising soil and protecting the landscape.

Understanding the Science of Erosion Control

The Basics of Soil Erosion

Soil erosion is the process by which the earth’s topsoil is displaced. This can occur through natural elements such as wind and water or be exacerbated by human activities like the removal of plants and improper land use. In Brisbane, heavy rainfall and the city’s hilly terrain often combine to create ideal conditions for soil erosion.

The impact of soil erosion on the environment and infrastructure can be devastating. It leads to the loss of nutrient-rich topsoil, which can negatively affect plant growth and agriculture. On top of this, soil erosion can lead to sedimentation in waterways, harming aquatic life and affecting water quality. On a larger scale, it can cause landslides and flooding, leading to substantial infrastructural damage and potentially endangering lives.

All too often as a maintenance horticulturist, I’ve seen poorly designed landscapes that encourage the soil to wash or blow away, day by day and year by year simply because the wrong plants were chosen.

The Role of Plants in Erosion Control

Certain plants play a better role in controlling erosion than others. Their root systems help bind the soil, preventing it from being washed or blown away. Additionally, the ground cover provided by these plants protects the soil from the direct impact of rain, reducing the likelihood of erosion.

By choosing plants with extensive, fibrous root systems, landscape architects can effectively harness nature’s own tools for erosion control, creating designs that are as resilient as they are beautiful.

The plants we’ll be discussing in this article are best at controlling erosion in the top 200mm of the soil profile. Trees with deeper roots are required to hold the deeper layers of the profile together.

Top Erosion Control Plants Thriving in Brisbane

Nafray® Pennisetum alopecuroides ‘PA300’ PBR

Nafray® Pennisetum alopecuroides ‘PA300’ PBR is a native grass with a finer texture than most, and it’s more compact. It’s a hardy plant that thrives in Brisbane’s climate and has excellent drought tolerance. The plant’s extensive root system significantly strengthens the soil, making it an excellent choice for erosion control. In landscape architecture projects, it can be used as a border plant, in mass plantings for ground cover, or as a feature in rockeries.

Strengthens the soil up to 475%

Katie Belles™ Lomandra hystrix ‘LHBYF’ PBR

Katie Belles™ Lomandra hystrix ‘LHBYF’ PBR is an evergreen Australian native with robust characteristics. It tolerates part shade and produces highly perfumed flowers, adding sensory appeal to any landscape design.

Its root system is effective for soil strengthening. It’s versatile and can be used in a variety of settings, from garden beds to pathways, and even in soggy conditions due to its tolerance of wet feet.

Strengthens the soil up to 285%

Shara™ Lomandra fluvialtilis ‘ABU7’ PBR

Shara™ Lomandra fluvialtilis ‘ABU7’ PBR is a tough, fine-leaf plant with blue-grey tones. It’s well-suited to humid climates and heavy soils, making it ideal for Brisbane conditions. It produces yellow flowers and contributes significantly to soil strengthening. This plant is perfect for mass planting, borders, and roadside landscapes.

Strengthens the soil up to 225%

Tropic Cascade™ Lomandra hystrix ‘LHWP’ PBR

Tropic Cascade™ Lomandra hystrix ‘LHWP’ PBR is a compact plant with weeping foliage and fragrant yellow flowers. It’s robust and can thrive in various conditions, making it a versatile choice for landscape architects. It’s an excellent soil strengthener and can be used in rain gardens, near water bodies or as a feature in garden beds.

Strengthens the soil up to 159%

Lucia™ Dianella caerulea ‘DC101’ PBR

Lucia™ Dianella caerulea ‘DC101’ PBR displays deep green foliage and produces purple flowers and berries. This plant significantly strengthens the soil and adds a splash of colour to the landscape. It’s perfect for mass planting, borders, or as a contrasting plant in mixed landscapes.

Strengthens the soil up to 433.75%

Breeze® Dianella caerulea ‘DCNC0’ PBR

Breeze® Dianella caerulea ‘DCNC0’ PBR is a fast-establishing plant that fills gaps and outcompetes weeds. Its blue and yellow flowers add aesthetic appeal, while its root system contributes to soil strengthening. This plant is suitable for ground cover, borders, or in containers for patio design.

Strengthens the soil up to 297%

Queen Mum™ Agapanthus orientalis ‘PMN06’ PBR

Queen Mum™ Agapanthus orientalis ‘PMN06’ PBR has glossy green foliage, tolerates frost, drought, and humidity, and shows excellent disease tolerance. It’s a great soil strengthener and can be used as a border plant, in mass plantings or as a single feature in a garden bed.Unlike other agapanthus varieties, this option has very low seed virility, making it a safer option for close to bushlands and waterways.

Strengthens the soil up to 283%

Little Jess™ Dianella caerulea ‘DCMP01’ PBR

Little Jess™ Dianella caerulea ‘DCMP01’ PBR is a dwarf plant with purple flowers and short compact canes. It’s ideal for small spaces and contributes to soil strengthening. It can be used in mass plantings, borders, or in containers for small gardens or patios.

Strengthens the soils up to 181%

Aussie Rambler™ Carpobrotus glaucescens ‘CAR10’ PBR

Aussie Rambler™ pig face is a prostrate creeping succulent with long trailing stems and deep pink flowers. It’s an excellent ground cover plant and is perfect for rockeries, coastal landscapes, and rooftop gardens. Its succulent nature makes it highly drought-resistant, an added advantage in Brisbane’s climate.

This plant’s main erosion control benefits come from its ability to shield the ground from the impact of rain. Use this plant on low-angled slopes but never steep embankments. It’s roots aren’t that deep and it can get heavy, causing it to slide down the bank if the ground is too steep.

Further research needed.

King Alfred® Dianella caerulea ‘JOHN316’ PBR

We saved the best until last. The aptly named King Alfred® Dianella blows almost any other plant out of the water in terms of soil erosion control. The only catch is that it needs to be pruned back hard every couple of years to prevent it becoming overgrown and then dying back.

Strengthens the soil by up to 752%

Incorporating Erosion Control Plants into Landscape Architecture

Considerations for Design

When selecting plants for erosion control, several factors must be taken into consideration. The soil particle size should be taken into account, as different plants thrive in varying soil conditions. For instance, some plants prefer sandy soils, while others do well in loamy or clay soils.

Climate is another factor. The selected plants should be able to withstand the climatic conditions of the area. In Brisbane, plants that are drought-tolerant and can handle high humidity are often most successful. Aesthetics shouldn’t be overlooked, either. While the primary purpose may be erosion control, the chosen plants should also contribute to the overall visual appeal of the landscape design.

Consider factors such as the plant’s colour, texture, size, and flowering period to bring joy to your designs.

Daniel’s Wrap

The use of plants for erosion control in Brisbane is more than a necessity – it’s an opportunity to contribute positively to the environment and create stunning landscapes. As we’ve seen, the right plants can not only protect the soil but also enhance the aesthetic appeal of a space.

As a landscape architect, you have the power to shape our environment. Instead of specifying the same boring plants time and again, I encourage you to continue learning about different plant species and experimenting with how they can be used for erosion control. All it takes is 5% of your plant palette to consist of novel (but tested) cultivars to make an impact.

Remember, every project is a chance to innovate, inspire, and make a lasting impact on our world.