Aquatic plants for attracting wildlife

Em Bowman is the director and founders of STEM Landscape Architecture & Design​​​​​​​

In our last article I wrote about a dam revamp we have been working on in Kyneton, and since then I have had many questions about what type of plants to use in water habitats. So, I hope I can shed some light onto your next garden project.

As we are all well aware, plants are an essential component for drawing in wildlife but when we think about creating wildlife gardens many tend to think of plants on land. Water habitats attract more biodiverse species and are a critical source of water and refuge, especially in urban environments where water can otherwise be scarce.

I typically group water plants into four categories: floating, deep-water, submerged, and marginal. Ideally you want to include a variety of each type. However certain plants require different water depths, sunlight, and temperature requirements and may not be appropriate for your pond. You may need to do a little research to see what is local to your area and best suited for your waterbody before beginning your project.

Most nurseries sell water-plants but there are some that specialise in aquatic plants. I recommend that if you are trying to attract wildlife, plant local native species. Many of these can be found at your local indigenous nursery. Another reason to promote native plants is because many exotic water plants can become highly invasive if they escape your waterbody. I must emphasise that everyone who owns a garden should be responsible in their plant choices. If you do decide to plant exotic aquatic plants, responsible disposal (in a sealed garbage bag) is very important as many weeds are accidentally spread through greenwaste fragments entering waterways.

If you are planting out your pond you will need to introduce soil to plant these plants into, this can be done by bringing in very large pots or adding soil in and around the edges of the waterbody. I recommend you add a screened topsoil (this means soil without floating material like wood chips). Avoid any pine based potting mix. Sandy loam soil is fine or if you have good topsoil on your property you can use that and add 30% washed sand to the mix. Add this soil around and within the pond by forming underwater ledges with rocks and logs.

Free-floating Plants

The leaves of these plants float on the surface and you will notice their roots hang underneath them, like little jellyfish. Some common native floating plants include Azolla and Duckweed (Wolffia australiana). Usually, they just appear in water bodies as they get carried in by ducks. Many people think that these plants are weeds, however they are really super plants. They are wonderful nutrient absorbers so when you see it on mass it usually means there are excess nutrients in your water. You can remove Azolla if it starts getting a bit much by scooping it out,  but don’t throw it away as it makes a wonderful fertiliser, spread it around your plants like mulch and your plants will benefit from the nutrients within.  Be very careful not to introduce exotic floating plant species like Water Lettuce and Frog Bit. These are highly invasive plant species, especially in warmer climates.

Deep-water Plants

The leaves of deep-water plants typically float on the water's surface, but their roots grow in the soil below (or pots). Avoid planting exotic water lilies in cooler regions or smaller water bodies, as they can outcompete and smother other vegetation. If you’re in a warmer tropical area, you can plant Australian native water lilies (Nymphoides sp.- there are 19 Australian species) but avoid exotic water lilies as they can easily become a noxious weed. Deep water plants include Ottelia (Ottelia ovalifolia), Nardoo (Marsilea mutica) and Running Marsh Flower (Ornduffia reniformis).

Submerged Plants

These plants grow partly or completely underwater. They are very important in water gardens as these plants release oxygen and filter out excessive nutrients but also provide shelter and habitat to aquatic species. These plants include Water Ribbons (Cycnogeton procerum) and Eel Grass (Villisneria australis).

Marginal or Bog Plants

I find that this category of plants is the most important and if you have a small pond these plants would be best suited for you. These plants are submerged or partly submerged in the water and include a variety of different species. Some of these plants include Myriophyllum crispatum, Myriophyllum varabilis, Hydrocotyle verticillata, Alisma plantago-aquatica, Eleocharis acuta, Juncus sp., Baumea sp., Baloskion sp., Lythrum salicaria, Craspedia variabilis and Brachyscome paludicola just to name a few. These plants are especially attractive to butterflies and dragonflies which bring in many insectivorous bird species. If you have a larger water body like a big pond, wetland or dam, rushes are particularly important for insects and birds, as the hollow stems provide perfect homes, protection and nesting material.

There is no limit to the number of plants you can add to the surrounding areas of your pond too. Adding a diverse array of plants and grasses with logs and rocks will provide food and shelter for both aquatic and terrestrial species around your pond. Some of my favourite terrestrial plants for around water bodies include Hop Goodenia (Goodenia ovata), Tussock Grass (Poa labillardierei) and Native Blue Bells (Wahlenbergia stricta). Beneficial native flowering species that you can plant around your pond provide a food source as well as surrounding protection from predators so that insects, reptiles, mammals and birds alike can enjoy a good old time around the water.