We’re paying more attention to our ponds than ever before, so why don’t we make them as colourful as possible?
April through to September (erratic British weather pending) is a time for ponds. Koi, goldfish, pumps, filters, and setting up or maintaining ponds are the themes of the season. But it’s also the key time for pond plants.
Pond plants have enjoyed a surge in popularity in recent years, largely down to Covid. With many working from home, sales have risen dramatically as more and more people choose to spend money on brightening up their gardens.
Well maintained foliage is good for ponds and their inhabitants. For one, wildlife benefits from the extra aquatic flora.
Note that plants aren’t just an aesthetic addition to your pond but also a functional one. They utilise nitrates from the pond water, using it to feed themselves. Thus, denying it to nuisance algae, all while creating a beneficial ecosystem for both fish and wildlife. And, if chosen well, they can bring a startling palette of colours with them.
Different plants serve different roles, make sure you research them so you utilise them to their best. Some cover the water, like the leaves of long-stemmed, deeper-dwelling waterlilies, (Nymphaea spp.). Equally, floating ferns (Salvinia natans) make a good option; the whole plant lives floating on the surface.
Utilising pond plants at the surface will provide shelter for aquatic life to lurk beneath. Whether it is a fish pond or a wildlife pond, the animals will appreciate it. They also block sunlight that could otherwise cause unsightly algae.
Meanwhile, submerged oxygenating plants can become a spawning medium for fish. They then double up as protection for the developing eggs and young.
Know your zones
Plants like to be within their ‘comfort zones’ in ponds. Some like to be fully underwater, whereas others may just like to be a little bit soggy. Kept in the wrong zones they may even die, so it is important to know the placement for each.
Most plants come with labels that tell you which area to place them. Failing that an experienced retailer can point you in the right direction.
You should know these five zones:
In zone 1 you’ll find plants which like to be a little wet. These sit outside the pond but remain damp. Think of bog garden plants like Primula.
Use these to soften the edges of the pond, making it blend seamlessly into your garden. Bog garden plants love the nutrients in regular garden soil. When kept too wet they can suffer with root rot and fungal diseases.
Zone 2, is somewhere between 0-15cm (0-6") deep. Here, plants start to dip into the water properly. This zone is suitable for most marginal plants as well as some potted oxygenators.
Marginals usually sit on a little shelf at the edge of the pond. If no shelves are available then an upturned plant pot will do just as well. Put these plants in the water so the pots are only just under the surface. Don’t let them drop lower than 5cm below the water’s surface.
Zone 3 is deeper, from 15-45cm (6-18"), and is best suited for deep-water marginal plants. Tall, grassy types of marginals like lesser bulrush (Typha angustifolia) work well. As do potted oxygenators like water crowfoot (Ranunculus aquatilis).
Zone 4 is the bottom of the pond. This zone is home to the quintessential waterlilies and other deep-water species such as water hawthorn (Aponogeton distachyos).
These plants will spend their life at the bottom of the pond around 50-100cm (20-40")depth. If you place a water lily in an area that’s too shallow, they will die. Adversely, if they are too deep then they will fail to flower.
Finally, zone 5 is the open water, for those plants that float on the surface. These are some of the easiest to keep.
With that covered, let’s now look at some of the more colourful plants you can use to spruce up your pond…
Marsh marigold, Caltha palustris
The Mash marigold is an all-time favourite, and a native British plant. The striking buttercup yellow flowers and hardy nature make it perfect for that initial pop of colour. It blooms early on in the season and is a great colourful pond plant.
It grows to around 60cm (24") into a beautiful dome of upright stems and will come back every year. If you cut it back after its initial flowering it will then flower yet again in late autumn.
As the name suggests it’s suited to zone 1 bog gardens. However, it’s so versatile that it will also happily take to zone 2 — pop it on a shallow shelf and watch it grow. The nectar from its yellow foliage caters to insects that appear early on in the year. It also provides much-needed cover for frogs.
Water mint, Mentha aquatica
As the name suggests, water mint produces a gorgeous aroma of mint when the wind blows. This plant produces delicate round clusters of mauve flowers in the summer. It reaches a height of 30cm (12") and its nectar-rich flowers attract a number of pollinators.
For best growth keep it in zone 1 or 2, but note that allowing this plant to dry out will leave it susceptible to rot. Try to keep it in a part of the pond where it receives full sun, or dappled shade at most, and it will thrive.
Scarlet lobelia, Lobelia cardinalis spp.
‘Queen Victoria’ Lobelia cardinalis produces a mass of striking scarlet flowers through summer on tall, deep maroon stems. growing to 90cm (36") in height — this is truly one of the more colourful marginal plants out there. The contrast of the red against the greens of other flora makes it a perfect choice for those wanting something different.
Because of its height I would suggest you tie it to a supporting cane to maintain its structure. Otherwise, it may become a little unruly or end up breaking clean in half. This is another versatile plant that can be in zones 1 or 2, as long as it is shallow.
It acts as a beautiful magnet for butterflies and insects. Remember to cut back any dying foliage in autumn.
Creeping jenny, Lysimachia nummularia
A hardy British native plant with an abundance of yellow flowers in summer on low trailing green leaves. It reaches around 45cm (18") in length. Utilise it in either zone 1 or zone 2 to blur the edge of the pond.
In the latter zone, the leaves can raft across the surface of the pond providing cover for creatures beneath. You can also find a ‘gold’ version available where the leaves are paler and golden coloured for that extra contrast.
Barred Horsetail, Equisetum japonicum
Tall and fleshy evergreen stems with black bars around them give this plant its common name. Although this species will not produce a flower, it is coveted for its markings alone.
It grows tall, eventually to over 80cm (31"). This plant adds interest in winter as it keeps its attractive green foliage. The Barred horsetail can take its place anywhere from zones 1 through to 3 to suit your needs. As long as the deepest end the water is not be more than 15cm (6") above the pot it will thrive.
As a marginal plant its reed-like structure can act as protection for small fish and visiting frogs and newts. The spread of this plant can be quite vigorous. If you are planting in zone 1 you might want to consider keeping it in a container to restrict its growth.
Water liles, Nymphaea spp.
A pond plant list isn’t complete without the water lilies. Ask someone to think of a pond plant and their immediate go-to will usually be one of these. They are probably the most famous aquatic plant.
They come in a range of colours from red to pink, white to yellow, and even copper. Large lilies (Alba, Marliacea Carnea and Gladstonia) may spread over 2m (6.5') of a pond’s surface. So they are suitable for large ponds, rather than small ones.
Smaller versions called pygmy lilies (Pygmaea Helvolva, Pygmaea Rubra) are available. These will only cover an area around 50cm (20").
Although lilies are generally hardy, they can be a little fussy. These are all true zone 4 plants, and most comfortable under the surface of the water at a depth between 50-100cm. The use of upturned plant baskets to raise the lily is especially useful when first introducing it to your pond. Lower it in stages, avoiding plunging it too deep at the start.
Remember to keep lilies away from running water. This including waterfalls, filter returns and fountains as they prefer still water. If your pond is in full sun the lilies will thrive. Feed them with a fertiliser stick that you push into the pots, or a liquid pond feed, as they are vigorous and hungry plants.
They flower from June through September if kept in optimal conditions. Each flower lasts around four days, opening and closing daily. You may not get flowers in the first year, and this is totally normal. Patience is a virtue with all pond plants, especially so with lilies.