plants drift freely on the water surface, adding
decorative interest to any pond. Care
should be taken when selecting as some are declared weeds.
How to choose floating
plants for your water feature?
plants are very fast growers and understanding this is
critical in deciding which ones to choose.
For most people, the decision is personal taste, but if you understand
the plants better, you can also base your choice on their benefits to your
plants reduce the amount of sunlight that can penetrate and can help in
the control of blanket weed and green water algae. Their ability to absorb nutrients from the
water can also aide with water filtration.
However if the floating plants overgrow
your pond, action needs to be taken to keep them under control.
Duck weeds, grown in warm, high nutrient conditions
can potentially double every 4 days.
However these plants are also a great food source for aquatic life
including fish, tadpoles and waterbirds.
The other benefit of duckweeds is in their ability to improve water
Azolla is an
attractive floating fern. It is
generally green in colour, but when grown in full sun, but can turn
pink-red. Azolla has been used in water
treatment as a powerful water filter, capable of absorbing large quantities of
pollutants including heavy metals. In water gardens excessive growth tends to
block out sunlight for other pond plants, so it is best harvested and used as
high nutrient mulch in garden beds.
Water Lettuces are
unusual floating plants, with soft thick leaves, forming a rosette
that makes the plant look like a lettuce or cabbage. The tiny little hairs on
the leaves help trap air bubbles and increase the plant buoyancy. The flowers are hidden within the foliage and
sometimes develop into small green berries. The plant also produces many
offshoots that in turn grow into more plants.
This is the main form of reproduction and leads to the formation of
dense mats. For this reason, Water
Lettuce can become a weed. However it
cannot tolerate colder climates. Water
Lettuce withers and dies when conditions fall below 18°C for longer than a
month. Therefore, it is highly unlikely
that these floating plants will become weeds in
the southern parts of Australia, where the Winters' fall well below this
Water lettuce is often used in tropical
aquariums to provide cover for fry and small fish. We use it in our nursery
(based in Victoria) to help out with improving water quality by placing plants
in ponds to compete with algae for nutrients in the water, thereby preventing
massive algal blooms.
Avoid aquatic weeds
Some floating plants such as Water Hyacinth
and Salvinia grow into large plant mats and are such strong growers, they are capable
of choking entire rivers. There have
even been reports on Water Hyacinth, claiming that they are amongst the world's
most troublesome aquatic weeds.
These two plants are declared noxious weeds in ALL areas of Australia,
and we need to make sure that we do not encourage their spread.
Water Lettuce and Water Caltrop are not declared weeds in all states of
Australia. This may be due to the fact
that the growing conditions may not be suitable for them to become a weed
problem. Please check with your relevant
- When disposing of excess floating plants, put them into your compost bin or
use them as a high nutrient compost in your garden. Do not use or dispose of them near
- Click on the following link for information on aquatic
- Click on the following link for information on algae
Please use our store locator to contact your nearest garden
centre, to place an order.