Pond Plant Varieties and Advice

Whilst they may not be the best decorative feature for big, boisterous koi, plants make great additions for nature and fish ponds of all over varieties. 

So let’s start with why they are not suitable for koi, these big fish are notorious diggers, anything submerged within the body of water will be turned over and tossed around unless it is of substantial weight with sufficient gravel on the top.  Therefore when building a pond it is a good idea to install a plant shelf of approx. 6-8” depth, this allows for sufficient depth for the plants to remain well watered in the root mass and also be shallow enough for the koi to not disturb once they are fully grown.  (As an added extra, it also provides shelter for smaller fish/fry should you be lucky enough for breeding!).  There is 1 other reason as to why Koi don’t go well with plants, although it is more of an indirect consequence.  The shelf upon which many plants sit is ideal for the heron.  Herons will happily walk in ankle deep water to fish for their prey, many koi keepers avoid such ledges to try and reduce the risk of damage from these adventurous nuisances to fish.

 

 

Moving onto the plants themselves! These can be a great addition for a number of reasons within the aquatic ecosystem. 

1. They compete with Algae for food resources such as Nitrates and Phosphates

2. Aesthetic – They look beautiful, especially in bloom!

3. They provide shelter for fry and insects

4. Certain species oxygenate the water

5. Roughage for certain aquatic species

What is the trick to potting aquatic plants without creating a mess? There are a few steps to take as follows;

1. Pre-soak your basket lining to remove any debris

2. Carefully arrange the lining, allowing for excess hanging over the back of the pot

3. Partially fill the basket with aquatic grade soil

4. Place 1 9cm plant per 3-4” of basket space

5. Fill the void space with the rest of the aquatic soil

6. Add any fertiliser tabs

7. Fold the remaining basket liner over the top of the soil

8. Cover in pea shingle/gravel to add weight to the basket and hold the soil in place

9. SOAK the soil to add density and weight, this will help prevent it becoming loose in the pond

10. GENTLY lower the freshly planted basket into your pond, allowing for escaping air and being careful to not upset the new soil.

Marginal Plants

Marginal plants can come in all sorts of shapes and sizes ranging from the larger, fast-growing and wide spreading Iris pseudacorus (yellow Iris) to the low lying, creeping Pennywort both of which are aggressive growers and if left unchecked can become a well rooted resident in the pond.  Alternatively the native Iris versicolor (Purple / Blue Iris) is a slower growing and more easily manageable pond plant.  The same goes for Equiestum japonica (Barred Horsetail) a steady growing plant that can be quite impressive once settled in, although in need of a low wind area as it can be prone to snapping under high winds.

 

Lilies

Lilies require deep water to thrive with plenty of sunlight.  Many people have issues getting their lilies to flower; sometimes this is due to the species being one that does not flower every year, sometimes it is because the crown of the tuber has been buried.  When planting a lily in your pond, always first make sure to drop them slowly.   Try not to get water on the tops of the leaves as this can damage the delicate foliage.  As the stems grow you can slowly drop the lily to its total depth.  Always make sure that the crown / upper section of the lilies tuber is fully exposed to the sunlight and not submerged.  This can also be achieved by creating a pit in the gravel where the leaves protrude from the pot. 

Lilies vary greatly in size, some Nymphaea species only cover 2-3 ft. with very small 3-6” pads whereas larger specimens can grow to cover several square meters of surface area so it is important to check when purchasing which you are getting.  It is worth nothing that only a few species are native to the UK, such as the Nymphaea alba which has a large white flower when in bloom.

Bog Plants

Bog gardens are a great way to use up any excess liner you may have from the creation of your pond! They easy to set up as well.  Simply take any offcuts of liner you have from the creation of your pond and pierce them at regular intervals.  Next dig a shallow pit (5-6” deep) at the desired location and use the perforated liner and fill with the excavated soil.  This allows the area to retain water without becoming overly saturated.  Then simply plant and enjoy! Add water mint (Mentha aquatica) to add a bit of fragrance to your pond/bog garden!

 

Floating

Water soldiers, floating hyacinths, water hawthorn, and water lettuce are all great varieties of floating plants, some of which that can flower in the right temperatures.  Be aware that water soldiers can sink in the colder months and rise again the following summer bigger and better than before.  Hyacinths, however, are a tropical plant and only last 1 season, unless you have a warm greenhouse you can store them in over the winter (this can encourage them to flower in subsequent years as the specimens mature). 

Be wary of duckweed being sold, it is a rampant plant and will quickly cover the entire surface of your pond blocking all light sources and clinging to all plants.  It Is advised that you avoid any plants exhibiting any signs of duckweed.

 

Oxygenating

Almost all forms of oxygenating weed are avid growers and provide great coverage for fish and fry.  Can be used to encourage spawning and provide roughage for your fish as they graze on the plants.  These really are a great all-rounder that should be in all ponds, not to mention that they provide passive oxygenation of during daylight hours.