King Alfred® Dianella

This ongoing study started in 2007 and is being updated constantly as new varieties are tested for their erosion control qualities.

It was found that the best plants for erosion control were Strappy Leaf Plants such as Lomandra, Dianella, Dietes and Agapanthus or Native Grasses like Pennisetum. This is likely due to their extensive root systems, which helps to strengthen the soil.

Top 10 Plants for Erosion Control

1. King Alfred® Dianella

King Alfred® Dianella is 752 percent stronger than bare soil.

2. Nafray® Pennisetum

Nafray® Dianella is 475 percent stronger than bare soil.

3. Lucia™ Dianella

Lucia™ Dianella is 433.75 percent stronger than bare soil.

4. Lomandra ‘Katrinus Deluxe‘

Lomandra ‘Katrinus Deluxe’ is 366 percent stronger than bare soil.

5. Nyalla® Lomandra

Nyalla® Lomandra is 328 percent stronger than bare soil.

6. Fine Divine™ Dietes

Fine Divine™ Dietes is 326 percent stronger than bare soil.

7. Breeze® Dianella

Breeze® Dianella is 297 percent stronger than bare soil.

8. Katie Belles™ Lomandra

Katie Belles™ Lomandra is 285 percent stronger than bare soil.

9. Agapanthus

The Agapanthus in the trial were 283 percent stronger than bare soil. Ozbreed have some great non-invasive Agapanthus choices.

10. Tasred® Dianella

Tasred® Dianella is 250 percent stronger than bare soil.

Latest 2021 Study Findings

Plant	% Increase vs bare soil	Shear strength kPa
Fine Divine™ Dietes	326%	38.5
Grand Star™ Dietes	228%	26.9
Shara™ Lomandra	225%	26.2
Evergreen Baby™ Lomandra	210%	24.8
Pacific Sky™ Lomandra	200%	23.6
Flat Mat™ Trachelospermum	140%	16.5

 

 

Past Research

Plant	% Increase vs bare soil	Shear strength kPa
King Alfred® Dianella	752%	70
Nafray® Pennisetum	475%	50.3
Lucia™ Dianella	433.75%	49.3
Lomandra ‘Katrinus Deluxe‘ PBR	366%	39.6
Nyalla® Lomandra	328%	36.1
Breeze® Dianella	297%	33.2
Katie Belles™ Lomandra	285%	32.3
Agapanthus	283%	32
Tasred® Dianella	250%	29.6
Tanika® Lomandra	250%	29.5
Katrinus Lomandra	216%	26.9
Little Jess™ Dianella	181%	24.3
Carex appressa	176%	23.8
Little Rev™ Dianella	161%	22.8
Tropic Cascade™ Lomandra	159%	18.6

 

Research Methodology

Ten large sample pots of each variety were grown and tested with a Shear Vane tester, as were samples grown in two different gardens. 29 shear vane tests were taken for each variety from the pots. The results showed all plants strengthened the soil compared to the control samples of unvegetated potting mix and soil. Increases in soil shear strength were analysed using an ANOVA test. Any variety that showed a 95 percent or more increase in shear strength was found to be significantly different to the unvegetated samples.

King Alfred® Dianella strengthened the soil 752 percent, and in this test had an undrained shear strength of 70 kPa, compared to unvegetated soil of 9 kPa. Many other varieties however, still strengthen the soil greatly. Katrinus Deluxe, a Lomandra longifolia, strengthened the soil by 366 percent. Some plants that are widely used in the USA and Australia, such as Liriope Evergreen Giant had much lower readings, only strengthening the soil a statistically significant 100 percent.

Varieties improved through breeding all strengthen the soil considerably more than their corresponding common varieties, providing evidence that plant breeding can lead to plants better suited to strengthening soil.

This data can help Engineers, Landscape Architects, and Erosion Control professionals choose plants that better strengthen the soil, and enhance erosion control of slopes, batters, stream embankments, roadsides, retaining walls, and shore lines. It will also provide a basis for future plant breeders to develop plants and turf that better strengthen the soil.

We Don’t Guess, We Test

When you choose an Ozbreed plant, you are backed by over 20 years of breeding experience and an average of 5-10 years of thorough testing on each plant.

If you want to read more about this study, you can download the full research article HERE.

Find out how Ozbreed can help you with your next project via the link below.