Oxygenating Plants
Your pond will need oxygenators to maintain a healthy ecosystem. These are plants, completely or partially submerged, which produce oxygen during daylight hours.
Like marginals, they will also reduce nutrient levels in the water, helping keep algal blooms under control.
Oxygenators are helpful for wildlife in your pond or stream too, providing shade, cover, egg laying sites, and - sometimes - attractive flowers for pollinators.
We supply two types of native oxygenator - Hornwort and a Water starwort, Callitriche stagnalis. They both occur naturally across the UK. We sell the Hornwort in bunches of 5, with 5 strands in each bunch. We recommend using both types in larger ponds for increased biodiversity. Reckon on roughly 2 bunches per square metre of pond.
The bunches are clipped together with a metal clip and just need throwing into the water rather than planting.
They deteriorate quickly in transit so we ship them by First Class mail, and recommend getting them into water as soon as possible on arrival. Like the Starwort, which we supply unclipped, Hornwort is naturally a floater, so if you like you can undo the clips and liberate the strands.
Native oxygenators are slightly tricky to grow, and have to be transported while in active growth. We offer two species, delivered between April and October. Deliveries may be subject to delay in the event of hot weather.
Hornwort (Ceratophyllum demersum): Hornwort is a healthy looking bushy plant which remind me of a fox's brush - hence its American synonym, Coontail. It grows in nearly all still water, from full sun to shade, and is found naturally in many places on the planet. It is fully submerged and grows in depths up to 60cm. Early in the season and if harvested from deeper water it will be brittle and appear black - don't worry! Even if they look very unpromising, if fragments break off they will grow very happily.
Water starwort (Callitriche stagnalis): This water starwort is native to the UK, although it's part of a 50 plant genus spread across most of the world. It has curious pretty leaves, which look more starlike if they're submerged, but rather different on the water's surface. Water starwort is an unfussy floating plant, forming rafts in sun or part shade and tolerating deep water. Start it off in around 20cm of water though. Good cover for tadpoles etc in Spring in particular.
A Plea
Whether you end up buying plants from us or not, please, please buy native rather than imported species like Parrot's Feather and Canadian pondweed. Not so much because non-natives might grow too quickly and aggressively for your pond - which is certainly a consideration - but because your pond plants can surprisingly easily escape into the wider environment (via birds' feet, for example). Once you have plants like these in your pond it's pretty much curtains.