Choosing the right plants for a pond or wetland ecosystem in your garden can mean the difference between a successful watery system, or one that fails to thrive long-term. Understanding and choosing the right aquatic plants can be crucial in developing biodiverse and sustainable systems and habitats on your property.
What are Aquatic Plants?
Aquatic plants are plants that thrive in water, or waterlogged soil, in or around the margins of a body of water. These are plants that thrive in habitats such as ponds, or in bog gardens or wetland schemes where water saturation remains high on a consistent basis.
Choosing Aquatic Plants
When choosing aquatic plants, as when choosing plants of any other kind, it is important to think about the growing conditions that you can provide where you live. Of course, this involves thinking about your climate and micro-climate conditions. Consider temperatures, sunlight and shade, and whether you are planting in a sheltered or exposed position, for example.
When choosing aquatic plants in particular, there are a number of other things to bear in mind. For example, you should think about:
- The depth of the water or degree of saturation of soil. Some aquatic plants thrive in deeper water (30cm or more), some in a depth of 15-30cm, some in 5-15cm of water, and others in very shallow water or waterlogged, boggy soil.
- The vigour and eventual size of plants you are considering. Some plants can be too large or invasive for a smaller pond, while others remain much more compact and contained and will be better suited to smaller projects.
- Potential for invasiveness where you live. Some aquatic plants can be problematic when they ‘escape’ into wild environments and so it is important to choose native plants where possible, and to avoid any that might pose a threat to aquatic environments in your area.
Types of Aquatic Plant
When choosing aquatic plants, there are four main types to consider:
- Aquatic plants that root below the water surface.
- Marginal plants (that like very shallow water or waterlogged soils.
- Submerged plants that oxygenate an aquatic system.
- & Floating plants that float on the water surface.
Where to Grow Aquatic Plants
Before you can choose aquatic plants, of course, you need to consider where you plan to grow them. In permaculture, there are a broad range of aquatic systems that we might consider in which aquatic plants will be required.
For example, we might use aquatic plants in:
- A garden pond.
- A larger pond or reservoir of standing water on our properties.
- Bog gardens
- Wetland restoration or rewilding schemes.
- Reed bed systems for water filtration.
- Aquaponic systems for food cultivation.
- The wettest portions of a rain garden to catch and store water on our properties.
Below, we will explore the first of these options in a little more depth.
Garden ponds are often a gateway to growing aquatic plants and can often be a good place to begin if you want to integrate permaculture ideas on your property. Creating a pond in your garden can be a wonderful idea, allowing to to boost biodiversity and create holistic designs for your space.
Why Create a Garden Pond?
Before you start creating a garden pond it is a good idea to explore why this is such a good idea, and to clearly determine your reasons for doing so. Thinking about your reasons for creating a pond can help you decide which type of pond you want to create, and shape its creation.
You might create a garden pond to:
- Aid wildlife in your area and bring more beneficial creatures to your space.
There are many reasons why a pond is a great addition to a wildlife garden. A garden pond:
- Stores water for wildlife to use for drinking and bathing.
- Provides a home for numerous aquatic and amphibious creatures.
- Creates a lot of ‘edge’ – increasing biodiversity in the garden system.
- Catch and store water in your garden.
Garden ponds can be integral parts of a water management scheme on your property. They can help catch and store water where this may be in short supply, increasing resilience on your land and allowing you to create self-sustaining systems.
They can also help manage water when there is a lot of it around, helping to maintain soil quality by reducing issues with excessive water, flooding, run-off and erosion. By helping you catch and store water on your property, they can also ( when carefully planted with aquatic plants) aid in filtering run-off etc. to prevent pollution issues downstream or downhill.
- To create a beneficial micro-climate.
Creating a body of water in the right location can allow you to create a beneficial microclimate. Water catches and stores heat energy from the sun during the day and releases it slowly when temperatures fall. So a well positioned pond can potentially allow for the growth of plants nearby that would not usually be ideal for winter conditions where you live.
- Provide a water source for backyard livestock.
A garden pond might also be useful for those who plan to keep ducks or other waterfowl, or other livestock on their properties. A pond can provide drinking water, nutrition, bathing water, etc. for the creatures we keep in our gardens.
- Provide edible yields for us.
A pond can also be designed to provide edible yields for us. Certain ponds may potentially be stocked with fish and/or other aquatic life that we can eat. They can be integrated into aquaponics schemes to grow plants too. And even where we do not stock fish in a pond, we can still consider a wide range of aquatic plants to grow in and around it from which we can obtain edible yields.
- Offer visual and auditory appeal, and recreation for human residents.
Ponds are not only practical features to include in a garden but also extremely aesthetically appealing additions to a space. A well-designed pond can look beautiful and also allow us to enjoy the sound of water on our properties.
Ponds can even become places to dabble the toes, bathe or even swim, if you decide to use aquatic plants to create a natural bathing pond on your property.
How to Create a Garden Pond
The process of creating a garden pond will vary somewhat depending on your specific priorities and goals. But the series of steps outlined below will help you to think through the key considerations and create the pond ready to plant up with aquatic plants.
Choose Where to Position your Pond
One of the most crucial steps in creating a garden pond is deciding where to place one. Of course, the placement of a pond will depend on your site, and what precisely you are trying to achieve.
You need to think about placement in terms of sunlight and shade, water flow (natural or directed through your own agency) wind, soil, existing vegetation, and to facilitate beneficial integration with other features within your design. Of course, you should consider safety and practicality, as well as other design principles of permaculture design when choosing the right spot.
Determine the Shape and Size for Your Garden Pond
Other important things to consider during the design stage are the size and shape of your pond.
The size of a pond may be dictated by space available, by topography, and by how much water you wish to catch and store. It may also be dictated by water needs, for cultivation or livestock for example. You will need to think about how deep your pond should be at the centre, and towards the edges, as well as its size in the horizontal dimension.
A pond for wildlife will typically have a depth of at least 60cm in its deepest part. Though the depth can also vary depending on how the pond will be used, and which aquatic plants you plan to grow.
Too shallow a pond may dry up too quickly in warmer, drier regions or freezer more quickly in colder climes. So be sure to think about these considerations. Typically, the larger you can make a pond, the easier it will be to maintain.
Remember, a pond should not be the same depth throughout. Do not dig a large deep hole with straight sides. Try to keep the shape natural and vary the depth, with a deeper section in the middle, shallower sides and one end that slopes gently upwards to a sort of beach area.
If there is not a gently sloping side, you will have to incorporate an ‘escape route’ for any wildlife that might fall into the pond and otherwise not be able to get out.
Consider a natural looking pond with waving curved edges rather than an unnatural geometric shape. By varying depth and maximising edge space you will create a large number of beneficial little ecosystems.
Remember, through shape you can maximize edge – where the aquatic ecosystem meets the terrestrial ones around it. And since edge is the most productive part of an ecosystem, we always seek to maximise it in permaculture design.
Mark Out and Dig Your Pond
Once you have decided where to place a pond, its dimensions and shape, it is time to mark out your pond and begin to dig out the area.
The edges of the pond can be marked out with string, or with stakes.
Depending on the size of a new garden pond, you might dig it out by hand, or use earthmoving machinery. In many cases, it is perfectly possible to dig out a pond by hand.
One thing to think about as you excavate the earth is how you might use this soil elsewhere in your garden. Topsoil might be removed from the area where the pond is to be created and used to create raised berms for planting close by, or removed and used to, for example, top raised beds for home growing created elsewhere within the space.
Decide How to Retain Water in a Garden Pond
Next, once you have excavated the soil, you need to think about how you will ensure that water is retained within your pond.
Ponds may sometimes be created where water naturally pools on a property. And, in areas with a clay substrate, the water may be contained without having to line the pond with additional materials.
In many cases, however, the water will simply drain away through the soil at the base of the pond if you do not take additional steps to compact, or line the area you have excavated.
Ponds created in areas with a lot of clay in the soil can sometimes be made to contain water by puddling the clay on the base of the pond, compacting it so less or no water can easily drain away through the base.
In areas with freer draining soils, clay can be imported from elsewhere to line the pond – often a more eco-friendly and sustainable solution than a plastic or rubber pond liner.
Not all methods will work well in all locations. In general, however, avoiding plastic where possible is the best approach. And it is certainly worth researching more natural methods using natural clay, or an imported Bentonite clay to retain water in your garden pond.
Fill Your Pond
Once you have created the pond itself, you should of course think about how it will be filled.
A pond in the right location, as part of water management on your property, may often fill naturally, or have water directed to it after collection from roofs, or directed through earthwork features from another part of your property.
Sometimes, however, a pond might be filled manually in the first instance. You should fill a pond with rainwater rather than treated mains water whenever possible.
The addition of a bucket of water from a nearby watercourse or another garden pond in the area will give your pond a helping hand in establishing a viable ecosystem. Though of course, it is important to make sure that you do not have a negative impact on any ecosystems from which you collect this ‘pond starter’.
Planting Your Pond Garden With Aquatic Plants
It is very important, whenever you are creating a pond or other body of standing water, to remember that aquatic plants of the various different types mentioned above are absolutely essential to making sure that the pond becomes a viable and healthy ecosystem. Without the right plants, a pond cannot possibly meet any of the desired goals discussed above.
Aquatic plants provide a range of functions in a garden pond. For example, the right aquatic plants can:
- Provide habitat, shelter, food etc. for a range of wildlife.
- Oxygenate the water for the benefit of other pond life. (Oxygenating plants in your garden pond release oxygen as a byproduct of photosynthesis, and this oxygen dissolves into the water. )
- Balance pH levels in the pond.
(Carbon dioxide lowers water pH, making it more acidic. So when plants absorb carbon dioxide and remove it from the water, pH will rise. The plants in an aquatic system, therefore, have an impact on maintaining pH balance.
Most natural freshwater features have a pH of between 6 and 8. But water acidification in both fresh and saltwater bodies is a major ecological problem caused by humanity and our emissions. Unpolluted rain should have a pH of 5.6, But most rain has a lower pH than this due, in large part, to fossil fuel emissions and other forms of pollution.
When acidity increases in aquatic systems, it can have a detrimental effect on both aquatic plants and aquatic wildlife. Algae and other non-desirable plant species are more likely to arrive. And aquatic animals will suffer, which in turn throws off balance in the system.)
- Promote nutritional balance within the ecosystem. (Pond waters too high in nutrients or imbalanced systems can experience algal blooms and other issues.)
- Provide edible yields for livestock and/or people.
It is important to make sure, with most pond ecosystems, that you have aquatic plants covering at least a third of the water surface, including plenty of oxygenating plants.
Failure to include enough aquatic plants is one of the most common causes of pond-related issues. So it is very important to plant up your pond as quickly as possible with the key species you have identified as working well and being beneficial for your particular pond, in your particular location.