If I had any mental picture of the entrance way to Cecil Sharp House, Regent’s Park Road, NW1, it was of something rather dry and gloomy, of being flanked by dark trees as one made a hesitant progress towards the non-obvious front door. It certainly was not of a vibrant flower bed.

Since last March, however, things have changed, and along the border to the left of the entrance is a series of bright lively beds set against a background of bark chip. With its scalloped edging the whole strip resembles a row of flowering buttonholes along a rich brown fabric.

This transformation, which has won a Camden in Bloom Best Business Entrance award, is the work of a co-operative group of gardeners called Permablitz London.

A permablitz is a sort of ethical garden makeover. Based on the sustainable principles of permaculture, all the work is voluntary but if you volunteer several times, your garden can then become the subject of a blitz. The idea originated in Australia and was taken up in London in 2013, since when there have been about seventeen events so far, with Cecil Sharp House counting as the showcase.

I met Susannah Hall to hear how the scheme works. Susannah, who describes herself as “left-leaning”, learnt typesetting at the last moment before it became obsolete, then immediately got to grips with the new technology. Her present career is a piquant mix of gardening and teaching IT, and she is a founder member of Permablitz London.

She says that principles of reciprocity underlie the scheme … underground reciprocity between the plants, creatures, fungi, bacteria, etc. to make a healthy fertile soil, and reciprocity between people. For instance, in the words of the scheme’s garden designer, Kayode Olafimihan, “Cecil Sharp House generously hosts the annual London Permaculture Festival. It’s been a pleasure to contribute a permaculture entrance garden by way of a thank you”.

I expressed surprise at the amount of work the blitzers had apparently managed to do in one day, back in March, at Cecil Sharp House. Well, says Susannah, it is surprising how much a group of willing people can get done, but only when the event is well planned and there is a design to follow. There were twenty volunteers that day, some of them local residents, an important point when it comes to sustaining the project thereafter.

Kayode Olafimihan designed the separate features of the long bed to break up the space, giving it a rhythm and adding up to an ecological, edible, decorative whole.

The features include a herb spiral, a pond, a compost mound and several group plantings arranged around three trees of the red fruited crab apple, Red Sentinel. With a nod to the importance of apples in folklore, and Cecil Sharp House as the home of the English Folk Dance and Song Society, there are other apple trees as well, a Saint Cecilia near the road and a Blenheim Orange further in.

The planting includes edible plants such as strawberry and tayberry, with many sorts of medicinal and culinary herbs, as well as those that the pollinators love. There are bird boxes, insect houses, logs, stones, every sort of blandishment to encourage small, helpful beings to move in and, it must be feared, small unhelpful beings as well. There are notice boards near the entrance, explaining the principles of permaculture and the activities of Permablitz London.

However, it is not that there has been no other gardening activity going on. Cecil Sharp House is surrounded by garden - the shady walk with yew trees along the side was graced with autumn cyclamen, with white Japanese anemone growing nearer the house and quite a lot of planting here and there. The huge plane tree in the walled garden, probably older than the house, may not be a help to horticulture but is splendid in its own right.