Garden ponds in the city
Advertisement feature by Swell UK, aquatics specialists: Chris Plum, Pond and Aquatics Specialist at Swell UK advises how to set up a pond in the smallest of urban spaces.
Whilst small spaces do not readily lend themselves to water features and ponds, there are ways to create a space with water. City gardens are not just a little bit of calm in an otherwise manic world, but are also great for introducing wildlife, and ponds are no exception to this.
My garden in Manchester, for instance, is a small yard with a tiny patch of grass and vertically planted hostas, but I have managed to fit in a pond. The pond is actually a sunken plastic crate, covered with rough stones including a ramp and small steps into the water for any wildlife to get in or out. The planting is basically water lettuce and water lilies- space doesn’t allow for a lot more than that. However, the great thing about the pond is the way it attracts the frogs and dragonflies which you would not usually expect in a tiny yard – and there’s the additional bonus that the frogs keep the slugs under control around my hostas!
The major problem with my pond is that it does not include a filter or pump, so I have to change the water very regularly and keep a close eye on the plant growth. In particular, blanket weed and algae have to be removed constantly to prevent the suffocation and death of wildlife within the pond.
The easiest way to remedy this would to construct what most people would consider a ‘proper’ pond complete with liner, pump and filter. Although bigger than my plastic crate, ponds do not have to be the massive lagoons that you come to expect from gardening programmes. Small pre-formed ponds are readily available and you can always dig a miniature one yourself directly into the soil. The key thing is the siting – you need somewhere that is not covered by trees or in too much shade or sunlight – a happy medium is best.
Whilst pre-formed ponds are the easiest to build, to get a unique shape, it is easiest to dig your own. Whilst digging you need to ensure that the pond is not just steep-sided but has a series of shelves for planting your marginal plants, which will also prevent wildlife falling in and not being able to get back out again. Once you’ve finished digging, remove any sharp objects and stones and then cover with a layer of sand to protect the pond liner from puncturing. Using a liner that is larger than your pond, carefully lay it in the space you have prepared and with your feet (in socks) make sure it is pushed into all the corners. You can then add water, a little at a time, to prevent air from becoming trapped underneath.
Pond Pumps and Filters
Ponds require a pond pump and filter to maintain the water in a healthy state. The pump circulates the water and the filter cleans it. Pumps and filters come in a variety of sizes and have different flow rates. The basic rule of thumb is to find a pump that can handle the volume of water. The volume in metres cubed is calculated by multiplying the length, depth and width of the pond together. 1 m3 is 1000 litres. You need to pick the correct filter for the volume of water and then the correct pump based on the filter. The optimum flow rate of the filter should be at least three quarters of your volume and your pump will need to be able to handle that.
Planting the Pond
Pond planting is not the same as garden planting unfortunately. You not only need to ensure that the plants are looking great and staying firm, but you also need to make sure they are not losing any soil into the water. To do this, plant marginal water plants in a basket, lined with hessian and put a layer of gravel on the top. Then submerge the basket in a bucket or fully soak with a hose to remove any air pockets within the soil before carefully placing it into the pond. Remember that deep water pond plants require a lot of feeding, so bear this in mind when planting and splitting or dividing.
When planting up your pond leave space for plants to spread. Most garden centres stock pond plants that are too forceful for smaller ponds which will soon take over. There are however some plants that are perfect – try these floating, marginal and oxygenating suggestions:
The best floating plants are those such as water hyacinth (Eichhornia crassipes) and fairy moss (Azolla caroliniana). Whilst these are invasive in the wild in the UK water system, in a domestic pond they are easily manageable. Water lettuce (Pistia stratiotes) and water soldier (Stratiotes aloides) are also good choices. Water soldier is a native plant to the UK but is increasingly in decline, so growing this will mean you will also be doing your bit for water plant conservation.
With marginal plants it is best to get the varieties that only require a shallow depth of water – like spikerush (Eleocharis acicularis) and corkscrew rush (Juncus effusus f. spiralis) which only require a depth of water of around six inches.
Oxygenating plants are vital for a healthy pond but most are too aggressive for small areas including nearly all the usual pond weeds. The best plants to use are willow moss (Fontinalis antipyretica) and parrot feather (Myriophyllum aquaticum). Both of these grow to manageable sizes without taking over, though they both will need regular maintenance.
The most popular pond plants are water lilies. However, most are far too big for a small pool. There are however a few dwarf and pygmy varieties which are ideal. The easiest to get hold of is Nymphaea candida, the dwarf white water lily, but there is also the even smaller Nymphaea pygmaea or pygmy water lily. Either of these would make an attractive addition to your water garden.
The key to pond success is careful planting and maintenance. Pick the right plants and the right location and you can give wildlife a tremendous boost and attract plenty of beneficial insects for the rest of the garden to boot. Perhaps it’s time to give a pond a go, whatever size your space.