Depending upon the size of the pond, aquatic plants may require to be placed in containers.
In smaller ponds, the use of containers can prevent plants becoming too large and invasive.
Wire mesh containers are rarely used now, having been replaced with perforated plastic containers.
The perforations in the containers allow for water and gas movement through the container.
On occasions the perforations in these containers might be quite large so it is better to line them with hessian or polypropylene fabric to prevent soil loss.
When filling the container aim for a medium to heavy loam, failing that, use ordinary garden soil providing it is free from fertiliser and herbicides.
Prior to filling the container, place bricks or stones in the bottom of it to give stability, particularly if planting taller plants,
Alternatively use proprietary aquatic compost.
Week 16- 20:
This is the best time for thinning out nymphea (Water lily)
After draining off the water, examine the rootstock and select the strongest rhizomes.
With a sharp knife, cut these back to 150-200mm (6”-8”) from the growing part and trim off the true roots beneath.
Purchased container grown plants may need potting into larger containers, and bare root plants should have any old roots and large leaves removed before planting.
Congested Plants in Pond
The following procedure applies to both divisions and new plantings;
Select a suitable sized container, fill it, and saturate the soil before planting.
- Large plants require soil 200-300mm 8”-12” deep in containers at least 500mm (18”) square.
- Medium plants require soil 150-200mm (6”-8”) deep in containers at least 300mm (12”) square.
- Small varieties require soil 100-150mm (4”-6”) deep in containers 225-300mm (9”-12”) square.
- Miniatures require soil 75-100mm (3”-4”) deep in containers 225-300mm (9”-12”) square.
Water lilies may he planted either directly into the base of the pool or in perforated containers.
When planting the rhizomes, set them so that the soil is level with the young growing part of the root stock.
Top off the container with shingle, or pebbles to prevent fish dislodging the plants.
When planting out choose a sunny position, and sink the container to a depth* that will position the rhizomes at the surface of the pond.
*Ideally place in shallower water than the maximum recommended for that the particular variety.(see plant label for details)
Any small or immature divisions can be nurtured by placing them on bricks and gradually lowering them into the pond as growth progresses, until finally they reach their optimum depth.
During the growing season, keep the water as clear as possible to allow light and warmth to penetrate.
Water lilies require little attention after planting.
However, excessively large leaves may be removed from established plants if desired.
If the plants do not require dividing, then just feed them with a specialist aquatic feed to encourage flowering.
Floating plants should be introduced to the pond by placing on the water's surface, at a density of one plant per sq metre (11 sq ft) of pond surface.
Prior to placing the plants thin/separate if necessary.
Avoid invasive plants such as Fairy fern and Floating pennywort.
When planting new bare root marginal plants, trim back the tops by half and trim the roots back to within 25mm (1”) of the crown.
- Divide and replant established marginal plants when necessary.
- Thin out and anchor oxygenating plants firmly into baskets in bunches of three or four stems per ¼ sq m (3sq.ft) of water surface.
Rinse the roots of pond plants to remove muddy silt, aquatic weeds or any unwanted insect life before planting.
- Avoid putting large quantities of plants into the pond, particularly if it contains fish.
These plants respire at night and large quantities can deplete a pond's oxygen levels, especially during summer, causing fish to die.
- Avoid invasive species such as New Zealand pygmy weed and Parrot's feather.