How To Plant Water Plants

Posted by Sunset Garden Experts on


After installing your pond, water plants can be introduced when the water has reached air temperature. Your aquatic ecosystem should contain the following: Oxygenators, Deep Water Plants, Marginals, Marsh Bog Plants and Floating Plants.

What are Oxygenators?
Oxygenating plants grow fast and will keep a pond clear and algae free. They grow underwater collecting nutrients from the water through their leaves and they then release oxygen. This why they form an important basis for the natural balance in a pond as they are extremely useful for keeping the water clear and healthy.

How to Plant Oxygenators
Put the plants under water, in coarse sand, gravel, clay pellets or special growth substrate. In nature these plants will root directly in the bottom. In most ponds this is inconvenient, because liner is lying on the bottom or a preformed pond has been used. You are therefore advised to always use pond baskets. (pond planter pots) Put your oxygenating plants in a pond which has a proper water quality (rich in minerals, so hard water) and enough CO2, then they will keep the water clear and algae-free. Opinions are varying about the number of oxygenating plants required to obtain clear water, however, a rule of thumb is 5 bunches per 1,000 liters of water.

When to Plant Oxygenators
Newly installed ponds contain in the beginning only a few micro-organisms and consequently they have a poor supply of CO2. Before putting in oxygenating plants, it is wise to let a pond develop for about 4 weeks’. Plant them preferably in their growth period, between April and June. After planting they will keep the water clear and algae free. If you want to put in oxygenating plants at the same time, oxygen will have to added to the water. For this purpose you can use so-called CO2 Tabs.

What are Marginals?
Marginal plants are those which grow around the margins of the pond where the water is shallow. They usually have their soil and crown underwater, and sometimes their lower foliage as well. They are generally placed on planting shelves within the pond. In order to be considered a true marginal pond plant, the variety must be able to tolerate waterlogged soil or water over its crown all year. A plant which will tolerate permanently moist soil but will not tolerate water over its crown or foliage, is considered a marsh plant. Marginals vary with different colours, heights and forms of leaf. There are plenty of possibilities.

How to Plant
Planting depths refer to the depth of water over the crown (growing point) of the plant, which is about the same as the depth of water over the soil level. So a plant with a recommended planting depth of 0 - 4 inches, should be grown anywhere from waterlogged soil (0 inches) up to 4 inches of water over its crown. Having less water than this does not usually matter, as long as the soil is not allowed to dry out, but you should not plant a plant in deeper water than the recommended maximum.

Marsh/Bog Plants
Marsh plants, sometimes called poolside plants or bog plants, are those species which can grow in permanently moist soil, but which cannot tolerate flooded soil or having their crown or foliage underwater all year round. Many plants sold as pond plants are in fact marsh plants.

Marsh plants can be planted around the edges of the pond, where the soil is wet. All marsh plants will also grow perfectly happily in a standard flower bed as a 'normal' garden plant. (Although they will obviously not tolerate drought, they do not actually require wet soil in order to grow well). Marsh plants generally prefer a position that is sunny to partial shade.

There is an extremely wide range of marsh plants with variations in colours, forms and sizes. You can really make your pond full of atmosphere with marsh plants! The biological function of the plants for a pond environment is determined especially by their growth potential. The more nutrients, the better they will be able to grow and in turn the more oxygen they provide in the water. 

How to Plant Marsh/Bog Plants
In newly installed ponds all kinds of marsh plants can be planted anytime once the danger of frost is past. The nutritive substrate in which you put them, should be as porous as possible. This is so that water that is rich in nutrients and rich in oxygen can reach the roots better to create better growth.

Use nutrient soil or growth substrate for exuberant growth and blooming of roots and plant. A great option is our water garden soil which you can check out by clicking here. If you are going to use a lighter soil make sure to cover the soil with gravel to prevent rinsing out. Add, if necessary, additional iron and trace elements.

Deep Water Plants
Deep water aquatic plants are those which grow on the bottom of the pond or on the deeper shelves, so that they have several inches of water over their crown (base of their stems). Their foliage and flowers either float on the surface like those of a waterlily, or partially emerge from the water. Those with upright stems offer important places for insects such as dragonflies to emerge, while those with floating leaves provide cover and shade for the pond helping prevent algae formation. The most common deep water plants would be water lilies and water lotus.

How to Plant Deep Water Plants
Spread roots out in a plant basket and fill with planting soil. (The roots serve only to anchor these plants as all nutrients come from the water and are absorbed by the leaves.) Place the basket at a depth of about 12" below the water surface. When the plant reaches the surface of the pond, lower the basket another 6".

Floating Plants
These plants float freely on the water surface with their roots hanging below. They do not need to be planted in any way and can simply be thrown in. As with oxygenating plants, they can help to combat algae and blanketweed, as they absorb nutrients from the water and provide shade, leaving less food and light for algae to grow. Additionally, their roots provide habitats and cover for certain pond invertebrates.

Floating plants are not winter hardy and will need to be overwintered in a bright room in a fish tank or something similar indoors. They can then be put out again come spring. The alternative is to simply repurchase a few each year as they multiply fairly quickly over the course of one growing season and are rather inexpensive. 

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