The River Oak is unmistakable because of its conifer-like appearance. The long, pine-needle leaves make it look like it more appropriately belongs in some Canadian snow vista than the Australian bush! Yet, it is a native and can be found growing near just about any body of water in the Illawarra and Shoalhaven.
Full grown River Oaks can reach nearly 45 metres tall and have a girth close to two metres. They flower in spring and produce small, brown, slightly spiky seed cones in summer.
As with all Casuarinas, River Oaks are gendered trees. Each tree is either male or female. Identifying the gender of a specific tree is fairly easy. First, only the female trees produce seed cones. If the tree has cones, it is female. Second, the flowers differ between genders. Male trees produce pollen-bearing flowers at the end of each pine needle. The flowers look just like extensions of the pine needle except yellowy orange in colour. Female trees however produce tiny, red, fluffy flowers in the fork or each stem just below where the pine needles start.
River Oaks are extremely good at controlling erosion. Planted on a bank, they quickly spread deep roots throughout the collapsing soil. For this reason, at Bangalee we use them exclusively for preventing further erosion of the Shoalhaven River. Their only main drawback is that they are very thirsty as seedlings. New plants must be watered regularly or they will not survive. This can be a bit of a hassle especially as they prefer to be planted in full sun positions.
Lomandra (Lomandra longifolia)
Lomandras are a large, clumping grass. They are very common throughout the Shoalhaven and can be found in many bushland environments, at the side of roads and in many people’s backyards. They are easily identified by their long, flat leaves and the spiky seed spires they produce in summer.
At Bangalee, Lomandras are primarily used for erosion control. We have Shoalhaven Riverwatch to thank for showing us just how effective Lomandras are at holding up the river bank. Once planted deep into the edge of an eroding river bank, they quickly form a solid root base and start to clump. If we want more, we can either germinate the seeds or simply cut up a clump into dozens of new plants.