This luxuriant growth is a mixture of Lemon Balm and Slender Knotweed (Persicaria decipiens), a water-loving plant native to this area.
They’ve both self-seeded here and they’re growing at the base of the slight slope on which my food forest is situated. They’re an example of what Geoff Lawton of the Permaculture Research Institute calls fertility (with a Pommy accent).
One of the things permaculture is about is nutrient capture. The nutrients in these plants represent a fertility source that can be returned to the soil to promote the growth of more plants, preferably the ones I want to eat. As water and nutrients flow down the slope, some is captured by the plants in the food forest and what escapes to the lower levels is captured by this layer of growth (there’s about 2 square metres of it).
So it makes sense to reclaim this fertility by slashing back all this growth and returning it to the top of the slope, as mulch, under the fruit trees, where it will rot down, return nutrients to the soil and start the process all over again.
Both these plants will regrow after slashing and I reckon I’ll get a couple more cuts out of this layer before the Lemon Balm goes into winter dormancy. The Knotweed will continue to grow through the winter and the Lemon Balm will come up through it again in the spring.
Below is another area of fertile growth—Native Mint (Mentha diemenica)—at the outlet of the grey water system. This also dies back in winter and will eventually be slashed back, after I’ve dried enough to use as a herbal tea in winter.
