Having the right balance of plants in your pond is essential and one type of pond plant that plays a very important role are submerged plants. Also known as “oxygenators” they play a key role in boosting oxygen levels in water as well as helping to filter out pollutants and reduce algae growth. There are numerous species and varieties to choose from with some been only partly submerged and having leaves that rise above the water level providing a safe haven for bugs, frogs and newts. Then there are the fully submerged varieties that help to create the perfect habitat for fish.
In the UK we have many native species of oxygenating pond plants suitable for ponds of all sizes and depths. If your pond is big enough It is recommended that you have a good mix of oxygenators to reap the other benefits they can have. In this guide to the best oxygenating plants for ponds we will be bringing you eight of our favourite British native species.
Top 8 Best Oxygenating Pond Plants In The UK
Water Crowfoot (Ranunculus aquatilis)
The Common Water Crowfoot or to use one of it’s lesser known names the “water Buttercup” is one of the hardiest of oxygenators and can withstand the harshest of European climates. This British native oxygenator flourishes in muddy pools with an ideal depth of between 15-60cm. The Water Crowfoot is a very short lived perennial that flowers in the summer producing beautiful white flowers about 2cm in size. In shallow water it attracts a wide variety of wildlife including bees, butterflies and hoverflies. It can take between 1-2 years to reach ultimate height of 10cm. Ideal for smaller ponds with a spread of 0.1-0.5 metres.
Pepper Grass (Pilularia globulifera)
Those that care for Britain’s plants and wildlife should consider adding pepper grass to their pond. This British native pond plant is under threat in the wild and is currently protected under the Wildlife and Countryside Act. Also known as pillwort it is a great oxygenating plant perfect for shallow ponds. It grows to a height of 15cm in an ideal depth of 30cm. Pepper grass is a creeping fern and can be planted as both an oxygenator or big plant giving it great versatility. Well suited to ponds with fluctuating water levels and moving water.
Mare’s Tail (Hippuris vulgaris)
Mares tails are an excellent pond plant great for providing oxygen, removing nitrates and attracting wildlife. They can be planted as a submerged oxygenator or as a marginal. They grow to a height of 20cm in a water depth of 8-30cm. The submerged part of the plant provides a safe environment for fish, newts, tadpoles and frogs. The foilage is a lovely blue-green and looks wonderful on a summer day. Classed as an invasive plant but not to be confused with Equisetum arvense also often called Mares Tail or Horsetail, which is an invasive weed.
Water violet (Hottonia palustris)
The water violet is a delightful pond plant that produces stunning lilac flowers in the months of May to June. In ideal conditions these can grow to 50cm tall, with the average been between 10-50cm. The water violet isn’t actually a violet and is a member of the primrose family. It provides excellent shelter for a wide variety of aquatic wildlife with dragonflies and beetles been frequent visitors. They are quite hardy plants which are generally pest free and overall low maintenance. With an overall spread of 0.5-1m they can grow quite big but take between 5-10 years to reach full size.
Frogbit (Hydrocharis morsus-ranae)
The frogbit is a small floating water plant that looks very similar to a water lilly. This British native floating aquatic perennial has small leaves and small flowers that grow to 2-3cm across. It flowers in the summer months and if you look closely at a frogbit flower you will notice a yellow spot on each petal. They are superb oxygenators and under the water they offer protection for small fish, frogs, tadpoles and aquatic bugs. They reach a maximum height of 10cm and can take up to 10 years to do so. There is no need to anchor this pond plant down just place it on the water and you are done.
Hornwort (Ceratophyllum demersum)
Also known as Cedar Moss or Coontails in the US, this pond plant is a good choice for those new to pond keeping. Hornwort is generally disease and pest free and doesn’t require pruining making it a great low-maintenance option. It can be grown in deep water with the optimum depth been between 30-90cm deep.
These perennials are free floating with dark green leaves throughout the spring, summer and autumn months. They flower during the summer months with the flowers themselves been very tiny. Hornwort grows up to 10cm above water level and can take 5 to 10 years to reach ultimate height. The overall spread is between 1-1.5m.
Water starwort (Callitriche palustris)
Water starwort is a good choice for ponds with limited space for a large amount of plants. In addition to boosting oxygen levels in the water they are also good for improving the overall quality of your ponds water making it a versatile plant. It is a native evergreen and provides an excellent habitat for an abundance of critters with newts choosing it to lay their eggs on it. It is suitable for ponds up to 80 cm in depth and produces good surface coverage, especially in the early summer. They also produce tiny white flowers in the summer.
Willow Moss (Fontinalis antipyretica)
Willow moss can be found in both fast flowing streams and still water ponds all across Britain. It is also a popular aquarium plant and has a striking resemblance to java moss. This hardy moss copes well with both low temperatures and light levels making it a welcome addition to British garden ponds. It can be grown in depths up to 1m deep and been an evergreen it provides useful oxygen during the winter months as well as coverage for fish.