Aquatic Plant Profile: Slender knotweed

Slender knotweed (Persicaria decipiens) is a sprawling indigenous plant for the margins of your pond. Knotweed is a low growing plant that will spread to 1.5m and form a dense thicket, it is fast growing and a great choice for cleaning up ponds with its effective ability to suck up nutrients from the water. Knotweed can be grown in most pond media such as sand, gravel, pebbles or just anchored in the water, it is not a fussy plant. 

The propagation method for Knotweed is by cuttings. Cuttings can be taken from the tips of the plant, preferably on stems that do not possess flowers, ensuring there are 2-4 leaves on each cutting. Replant in a medium like gravel or sand and you will create new plants very easily.

Interestingly, Slender Knotweed was a species collected by Joseph Banks on the 5th of May 1770 at Botany Bay.

When used on pond margins knotweed provides an excellent habitat for frogs and small fish to seek shelter within.

Knotweed will have a small amount of dieback in Winter months however it does not have a dormancy period and will be still somewhat lush during this time.

Knotweed will grow above and below the water's surface, generally planted about 10cm underwater, but will only flower above the water, the pretty pink flowers add a great pop of colour mostly from November to June however it is common to extend past this. The flowers are also frequented by insects such as bees and butterflies.