Small Pondweed (that’s it’s name – not just a description of its stature!)

Small Pondweed (Potamogeton berchtoldii) seems to be growing well in the New Pond. This native plant - which occurs the length and breadth of Britain, should be within everyone's reach to grow in a clean garden pond

Most garden ponds have a pretty poor and unnatural selection of submerged plants.

This is down to a combination of factors:

– Native water plants can be quite difficult to get started;  clean, unpolluted, water is more or less a pre-requisite, and even then they don’t always take.

– Garden centres don’t supply any native submerged water plants except (if you’re lucky) Rigid Hornwort and Spiked Water-milfoil. Worse, many still provide what they call Elodea crispa – more correctly known as the non-native Curly Waterweed (Lagarosiphon major) – which originates from Southern Africa. This plant has escaped into the countryside where it is probably competing with native plants and, at least in some places, adding yet another threat to our native freshwater wildlife.

– The best source of native submerged water plants – the wild – is often apparently ‘out of bounds’ with many organisations repeating the misleading idea that it is generally illegal to collect any wild plants (it isn’t – except for some specially protected species it is legal, with landowners permission, outside of protected areas). It is understandable why conservation organisations have opted to promote this simple message – (see here for example) – but this message certainly hasn’t helped reduce the spread of non-native plants in freshwater. It is worth remembering that 6 out of 10 garden ponds have non-native species whereas only 1 in 10 in the countryside do, so the safest place to get native submerged plants is the ‘wild’ rather than other garden ponds.

All in all, in my experience, most garden ponds are a bit of a disaster area for plants. But it doesn’t need to be like this.

So in my New Pond – to which we are adding plants – we’re pleased to see the signs of native aquatics getting going. Stoneworts from the local gravel pits are beginning to take; the plant above – Small Pondweed (Potamogeton berchtoldii) – looks to be growing well, we have some little bits of Water-violet (from another local source – a pond we created to strengthen the population of this and other  uncommon water plants in another part of Oxfordshire) and we are hopeful that Blunt-leaved Pondweed (Potamogeton obtusifolius, from Pinkhill Meadow near Farmoor) and Least Pondweed (Potmogeton pusillus) from a village pond in Appleton about 5 miles away will also take.

Already with three aquatic plants growing successfully, and perhaps as many as five in due course, this pond has more submerged plant species than the average countryside pond – shockingly this is just 1 species of submerged plant (read the report here) – and about the same number as the average for top quality unpolluted sites.

The question now is whether garden ponds could actually help spread our threatened native water plants or are merely places where plants collected in the wild come to die.