Aquatic Plant Care

Aquatic Plant Care

All plants are beneficial for the pond environment. 

Too provide a great biological and healthy environment in your pond there are a few basic points around the care and upkeep of pond plants that will help you get the best out of your plants.

The general rule for Aquatic plants outside of the focal group ( Waterlilies, lotus) is to provide cover, habitat and hygiene to the pond.


Cover in a pond sense means protection from wind, sun and predators. 

Great examples of this are taller margin plants like Pond pickerel, Cyperus varieties, grasses or rushes or the range of aquatic Iris. These plants have enough height to shade margin areas of the pond breaking wind gusts to aid protection to fish and other pond life.

Areas of shade help with a balanced pond and provides areas for bugs and insects to multiply and provide food for your gold fish and frogs. 


Your pond area is its own little world.  

You are providing areas to sustain:

  • plant life - for colourful displays, food, cover from predators, and basic filtration
  • aquatic life - not just gold fish and frogs, aquatic life includes water borne insects, pollenators, etc
RULE OF THUMB - at least 75% of your pond should be covered with plants

Submerged aquatic plants are a great addition to any outdoor water garden or pond.  In most New Zealand temperatures submerged plants will keep growing (slowly) through winter slowly feeding off the nutrients in the pond.  Coming into Spring there is a lower likelyhood of a algae bloom while dormant plants (like water lilies) come out of dormancy.

For Gold fish look for finer leafed submerged plants. These are ideal for fish to spawn in also providing vegetation for goldfish to graze on with added benefit of hiding places for fry fish. Many other submerged plants create excellent homes for species like frogs and dragonflies.


The wider the range of plants in your pond, feeding from the water, provides an excellent filtration of nutrient - lowering the risk of algae problems.

All plants, in particular large root mass plants like Aquatic Iris, Cyperus varieties, Acorus - Japanese rush, Caltha Palustris - Water buttercup, Juncus rush varieties and Hygrophilia Augustifolia (Blue hygro), are gross feeders of nutrient in ponds.

When planted on the margins of your pond in an aquatic basket the roots have easy access to the nutrients in the water and reduce the availability for growth by algae.

A good root structure with green lush foliage from your aquatic plants is a sign of a very happy plant.

Be aware that large root growth with a small unhealthy plant could mean a lack of food.  The plant is putting all its energy into root structure looking for food in the water.  If this is the case add Aquatic fertiliser tablets or Aquatic Season long pellets into the soil of the basket to provide added nutrient to the plant.  

Alternatively Ecopond have a liquid Aquatic Plant food that can be added to the pond water to increase nutrient availability in the pond, it also has an algae control included  

Planting - Aquatic baskets

When planted in a specific aquatic basket with low nutrient aquatic soil (see picture) they quickly go to work drawing nutrient from the water by pushing their roots out of the basket holes. This process is done by all pond plants if potted correctly. Other positive results are long frilly roots create great spawning matter for fish.

Pond plant baskets are available in many sizes and shapes. 

There is not right or wrong in square, round or contour.  Basically if it works for your in your pond its right.

If you have rounded edges around your pond, the Contour basket is an excellent option.  Perfect for creating a curved feature with your marginal and deep marginal aquatic plants.

The Pond life cycle in New Zealand

Nearly all pond plants are seasonal with the odd exception. 

During the late summer months pond plants will start to show the signs of heading into dormancy. Reductions of flowers, leaf fall and less re-growth are all very common. This is standard with ponds and includes waterlilies and lotus. Don’t panic! Treat your pond much the same as the rest of the garden with light pruning and removal of dying foliage. This helps to keep the organic loading on the pond low as well as reducing the frequency of filter maintenance.

Late winter to early spring is the time to consider pond preparation for Spring. One task not given much thought is the care required to get the best results out of all pond plants. Waterlilies tend to get plenty of care, where the rest of the pond plants usually get forgotten about.

Not all plants will require yearly division or even that much care but it pays to check. Plants out growing their basket are the most common concern however this can be advantageous as the plant is working hard to find food. If it is growing well and you like it, don’t be afraid to try division to increase quantity. The general rule for pond plants is the more the better, with the exception of so many there is no room for the fish.

Some other more delicate specimen plants may require a simple re-pot and trim just to provide it the ideal start to the season.

Lotus & water lilies go dormant in New Zealand.

Water lilies are separated into two destinct variations:

Hardy Water lilies:

These are a rhizome/tape root based plant.

The main root has a central growing head and root stucture.  As the rhizome grows the leaves and plantlet grow from the main root structure.  Older growth leaves die off over time and the older growth of the root dies off and provides food for the plant.

This old root often rots and can be cut off and put into the compost.

Hardy, as the name states, allow the roots to grow in deeper water at cooler temperatures.  Flowers sit on the surface of the water 

Depth preference varies depending on the variety.  Suggested starting depth from 400mm to 600mm.  Plants will grow and expand to deeper areas depending on sunlight and water temperature.

Tropical Water lilies

Tropical water lilies grow well in New Zealand.  Tropical may seem off putting but these plants grow in lakes and ponds that freeze over in winter.  As long as the korn/bulb is not frozen it will do well in New Zealand conditions.

Tropical water lily flowers stand above water surface and are more vibrant in colour with sharper looking petals. Instead of a taper root the Tropical Lily has a hard bulb root that grows small juvenile bulbs from it. 

Tropical Lilies need regular fertilising and full sun to bloom through late spring and summer.  Flowers can cut and used in floral arrangements with flowers opening & closing as they would in the pond.

Depth preference of 400mm below the water surface.

Fertilising may be required but you must be a little cautious not to overload the pond before the plants have really shot away. If you use too much fertiliser too early in the season, algae may take hold before the pond plants are into their growth cycle, thus causing the green!

Aquatic Fertilisers

Using a good quality liquid fertiliser like Ecopond Aquatic Plant Food Plus not only supplies a balanced diet to all aquatic plants it also inhibits the growth of algae.  The added attraction to this product is the ease of use.  Just take pond water in a watering can or bucket, add the correct dose of Plant Food Plus and pour back into the pond.  No need to push tablets or pellets into the aquatic plants soil.

Tablet fertilisers, like Glenbogal Aquatic brand tablets or pellets, provide added nutrient to the plant through slow release in the aquatic soil.  Tablets provide added nutrient for plants in maintenance doses or season long slow release for aquatic plants lacking in the correct nutrients.  These should be used sparingly as the preference is for your plant to feed from the water and reduce algae problems.