Planting your pond

Why Have Plants in Your Pond?
Nearly all ponds will benefit from having a good selection of plants, not least because they give the area a more natural and informal feel. Plants serve many other useful functions too:

• They attract wildlife to the pond, providing food, rest and breeding sites for a host of creatures.

• They improve the aesthetics of the pond, breaking up hard edges and bringing colour to the area.

• They are used as spawning sites by pond fish and other creatures.

• They offer fry and other baby creatures food and protection.

• They produce oxygen and use up carbon dioxide.

• They shade the pond, providing cover for the fish and preventing excessive algal growth caused by high light levels.

• They remove nutrients from the water, which would otherwise build up and encourage the growth of algae.

It is therefore not only aesthetically pleasing, but also beneficial to the pond environment to have a good selection of pond plants. Tetra’s specifically formulated aquatic compost and AquaPlanters make it easy to achieve healthy plant growth.

What Types of Plant are Available?
There are five basic types of plant that you can use to achieve the look that you want to create:

Water lilies
Water lilies and other lily-like plants grow in deeper areas of the pond, sending up leaves to the surface.These floating leaves are ideal for shading the pond, and fish will often bask under them on hot, sunny days.You should aim to cover around a third to one half of the pond with floating leaves (floating plant varieties can also be used to do this). If you are just using water lilies for the deeper sections of the pond then they can be planted at a rate of one for every 1.5 – 3m2 (16 – 32ft2) of surface area (the exact amount will depend on what size the lilies are). There are many different varieties of water lily, ranging from small pygmy strains, such as Nymphaea ‘Pygmaea Helvola’ which has a maximum spread of 60cm (2ft) and is happy in less than a foot of water, to very large ones, such as Nymphaea tuberosa ‘Richardsonii’ that can have a spread of 2.7m (9ft) and needs a depth of 90cm (3ft). Lilies tend to start flowering when the water temperature exceeds 18ºC, with the blooms getting steadily more impressive as the season progresses. Each bloom tends to last around 4 days, with the flower opening in the morning and closing again in the evening.

Marginals
Marginal plants are those which are suited to shallow areas of the pond, although there are a few that will tolerate deep water (these are normally marked as “deep water marginal”). Generally, they can only cope with having a few inches of water covering their containers, and therefore a special marginal shelf is usually incorporated into the pond to accommodate them.This shelf should be around 30cm (1ft) wide, and about 20 – 23cm (8in or 9in) deep. Marginal plants come in all shapes and sizes, from tall grasses and irises to low, creeping varieties.They can provide shelter from the wind and a safe refuge for all manner of pond life. Taller varieties can also help to shade the pond, although this is best done with floating leaves.

Oxygenators
Oxygenating plants, such as Canadian pond weed and water milfoil, are so called because they produce oxygen during the day as a by-product of photosynthesis.Their name can be a little misleading, as at night they stop producing oxygen, yet they continue to respire and use it up. In a moderately stocked pond, the amount of oxygen used up at night is not usually a problem, and they benefit the pond environment by providing good spawning sites for fish and other creatures. They also create a refuge for fish fry and other small pond creatures, and provide homes for a variety of invertebrates which fish like to eat.Their rapid rate of growth also makes them ideal for natural algae control.
Oxygenating plants often come in bunches, and should be added to the pond at around 5 bunches for every square metre (10ft2) of surface area.They will need occasional pruning to keep their growth under control. It is often easier to plant bunches of oxygenating weed in a pond basket or AquaPlanter, as this keeps them in one place and allows them to be more easily removed if necessary.

Floating Plants
Floating plants are usually only available in the summer, asthey do not over-winter particularly well.The majority of them will either require replacing every year, or overwintering indoors in a bucket of water (adding a handful of TetraPond Aquatic Compost to this will provide them with the nutrients they need).
There are quite a few varieties of floating plant available, such as water hyacinth, water soldier, frogbit, water chestnut, and so on.Their root systems dangle in the water and provide good spawning sites for pond fish, as well as extracting nutrients from the water that would otherwise encourage algae.They are very useful for providing shade for the pond, as well as offering a home for invertebrate life upon which the fish may feed.
In order to give them sufficient room in which to multiply, floating plants should be added at around one for every 1 – 1.5m2 (10 – 16ft2) of surface area. Some varieties will grow very rapidly and need occasional thinning out.

Moisture Loving Plants
Moisture loving plants are those that require permanently damp soil, but that will not do well in any depth of water. They are ideal for bog gardens and can add a whole new dimension to the pond, often attracting all sorts of wildlife to the area. Some varieties of plant will do equally well on a marginal shelf or in a bog garden, and so it is important to check information labels to see exactly where you can put a particular plant. Bog garden plants are best moved and divided during either the spring or autumn, and in the spring the soil can be perforated and the area given a general tidy up.Autumn is a good time to dig over the soil, so the winter frost and rain can break it down for the spring. Moisture lovers are not planted in pond baskets like other aquatics, but instead placed directly into the bog garden soil. Under no circumstances should pond plants, or cuttings of plants, be released into the wild. Doing so could potentially pose a threat to native species. Always carefully dispose of dead plants and cuttings, or ideally add them to the compost heap.

Planting
The best way to give your new plants a healthy start is to repot them, replacing the soil they come in with a good quality aquatic compost. TetraPond Aquatic Compost has a high loam content that prevents clouding of the water, and a slow release fertiliser that encourages lush plant growth, whilst discouraging the growth of algae. It is also fully sterilised to prevent the introduction of pests and diseases. New plants should be housed in baskets or Tetra AquaPlanters that are large enough to allow for expansion. The larger the container they are in, the longer it will be before they need re-potting. Tetra AquaPlanters are designed from a unique flexible material called ‘Plantex’, which allows water through but is strong enough to contain root growth. AquaPlanters will also prevent compost from leaching out into the water, and so there is no need for the use of cumbersome hessian lining. Because the material is flexible it can be folded down to the correct height for the depth of the marginal shelf, removing the problem of having unsightly basket tops sticking out of the water.
The reason aquatic plants must be placed in perforated containers, and not ordinary flower pots, is that their root systems need a flow of water to them in order to supply nutrients and oxygen.This aeration of the soil prevents it from becoming anaerobic (depleted of oxygen) and foul smelling.
Once you are ready, you can plant up your aquatic plants using the following procedure:

1. If you are using an ordinary pond basket, line it with hessian to prevent compost leaching into the water. If you are using an AquaPlanter, open it up ready for filling.
2. Start filling the basket or AquaPlanter with aquatic compost, firming it as you go.
3. Remove the plant from its original pot, make room for it in the compost and place it in its new container.
4. Firm more compost around the plant and add water to it in order to drive out any trapped air.This may cause the compost to sink slightly, in which case more should be added.
5. The compost should then be topped with around 1 – 2cm (0.5 – 1in) of hard gravel or pond flint, in order to stop the fish from digging into it, and to stop it lifting out of the container when it is submerged.
   

Ordinary soil or garden compost should not be used as it is unlikely to contain the correct balance of nutrients required by aquatic plants. It is also likely to encourage excessive algal growth and can contain contaminants that might be harmful to pond life.The same method can be used for re-potting plants when they out-grow their containers.At such times the plant can either be divided up and planted in the same sized container, or simply moved to a larger one.
With water lilies, make sure that you use a large container, with at least 15cm (6in) of compost.When you re-pot them it is very important to place the growing tip (or “crown”) so it is exposed to the water, and in the same position as it was in its original pot.

There are two approaches to the introduction of lilies to the pond, the first being the more traditional approach:

1. Lower the lily to its final position in the pond slowly,starting off by covering it with only 15 – 25cm (6 – 10in) of water. It can be supported on bricks or upturned baskets, lowering it by around 15cm (6in) at a time over a period of a year or so.This is done because lilies do not adapt well to sudden changes of depth, the effects of which can include checked growth, small leaves and poor flowering.
2. Alternatively you can cut the lilies foliage back to its crown and place it at the bottom of the pond. New growth will then start to appear in the following weeks and months.
   

If you plan to plant the lily very deeply then it may be advisable to stick to method one, but in shallower ponds either approach should work.
When selecting your new plants there are a few things to look out for.The best ones are those that show signs of new growth, and that are not damaged or stunted. It is also wise to look out for signs of pond snails or eggs (which appear as clear jelly-like masses attached to leaves), and wash them off before the plant is potted up.

Symptom - Small, black aphids on lily leaves.
Likely Cause - Water lily aphid.
Action - Spray nearby fruit trees in the winter with an ovicide to kill eggs. Knock aphids into water with hose where fish can eat them.

Symptom - Small dark brown/black beetles, and tiny black larvae on lilies. Causes disfigurement of leaves.
Likely Cause - Water lily beetle.
Action - Knock beetles into water with hose. Tidy up pond side vegetation during the winter.

Symptom - Jelly-like masses appear on leaves. Plants eaten away.
Likely Cause - Snails, in particular greater pond snails.
Action - Float a lettuce on the surface of the pond and remove when covered in snails.

Symptom - Dark patches on surface of leaves.
Likely cause - Water lily leaf spot.
Action - Remove affected leaves and discard.

Symptom - Sudden blackening of leaves and flower stems. Rootstock goes gelatinous and foul smelling.
Likely cause - Water lily crown rot.
Action - Remove all affected plants and destroy them. Remove fish and disinfect pond. Wash out pond and put fish back.

Plant Pests and Problems
Just like fish, pond plants may at times suffer from various health problems.The following table will help you identify and resolve some of these:
Following these simple tips and using Tetra’s aquatic planting products will ensure that you are able to create a beautifully planted pond with the minimum of trouble.