The Sombrun Forest Garden Project

This year has been a shock. The garden has suffered from severe frost and drought and as mentioned last month, I have realised that there has to be a fundamental shift in my approach to the Sombrun Forest Garden Project. Frost I can’t do much about, as this will vary from year to year, and will no doubt continue on a ‘win some, lose some’ basis. But there is a high likelihood of extended summer drought from now on due to climate change, and I can at least plan to mitigate this.

It means that the immediate focus needs to be on water management, to develop further from the swale ditches already installed in order to help the trees, shrubs and other plants to survive. This will now take priority over further planting (although there will be some, see below) until I can see the way forward to resume. My thinking is that unless I can give Nature a helping hand to improve the conditions for survival, the Forest Garden will always struggle, given the initial poor soil and the slope on this site. I was even watering this month, September, which has never been needed before.

My ideas are continually evolving, and now as well as installing hügelkultur beds (see last month’s Blog) to improve water retention in certain areas, I have decided to bring forward my plans for rainwater harvesting (see Blog, August 1st, 2021). This will involve repositioning the guttering on both sides of the house roof, bringing the rainwater round to the back of the garage, and directing it into three 1,000 litre tanks for storage. A fourth tank will be sited in the top northern corner, in the Coppice (the garden’s highest point), and water pumped up to it from below, using a solar pump. From there, gravity-fed drip irrigation pipes will be moved around to provide water overnight for those plants most in need. It is unsustainable and costly to continue watering with mains water, quite apart from the fact that it became illegal at one point this summer!

All rainwater guttering from both sides of the house will lead to the back of the garage (above left), where three storage tanks will be installed. This water will then be pumped as needed to a fourth tank sited at the garden’s highest point in the Coppice (above right), to allow gravity-fed watering.

So now the work can begin, and this will be my main focus over the winter. As well as looking into raising some finance for the rainwater harvesting project and getting a local artisan to do the work, I will be able to mark out the areas for the hügelkultur beds and get these prepared.

The main activity in the Forest Garden this month has been cutting the season’s grass. I developed a cycle of scything-raking-strimming-raking and ended up with grass piles all over the garden, as shown in last month’s Blog. These were then spread in the swales and on their banks, and also around all young trees; this provides a biomass mulch and becomes a key element in the water retention strategy on the site (photos below). The grass biomass is important in the swales themselves, since there is also woody biomass already there, and the decomposition will provide valuable nutrients, and mycelial and invertebrate activity, as well as keeping the whole swale damp.

The paulownia hedge was ‘refitted’ after the summer’s drought damage, using saplings that I had retained in pots. Nearly half the original hedge had been lost, and I decided to increase the spacing of the new plants to 80cm to allow them more root room. There are now 20 plants in all, and they were planted just in time to benefit from the substantial rain we had right at the end of the month. In the photo below, the plants with paler leaves are the transplanted saplings (they were lacking nutrients in their pots) and the darker ones those that I retained. Both types had good root systems, so I hope that by transplanting this early they will have time to develop them even further before the winter cold sets in. The hedge continues right to the driveway spur in the background.

I had planted two sea buckthorn, male and female, in the gap between the walnut and the early cherry in the Lower Garden last winter but they were suffering from the juglone effect – the chemical that walnut trees diffuse from their roots to discourage most other types of plant growth – so they were lifted, pruned and potted, and now they are already putting out new shoots (photo below). I want them in the Lower Garden as they are nitrogen fixers, but haven’t found a place for them yet.

As we started to get some serious rain at the end of the month, I harvested the squash crop to bring them in to the dry, and am more than satisfied with the result. There are Courge d’Eysines (with the ‘barnacles’), butternut (foreground), and two types of pumpkin. As mentioned last month, they will easily keep me going in soups for the winter!

I wrote last month about pioneer species in the Forest Garden, and I shall be planting some acacia saplings (from the forest over the road) further down the slope in the Upper Garden, around the fruit trees there. Pioneer species establish quickly and have a tendency to take over unless watched. I don’t find them a problem, and the advantage is that they will help colonise the ground and create conditions for soil improvement and shade, and provide valuable habitat for biodiversity; they also become a part of the water management strategy. I will probably treat them as coppice material, so they will be selectively cut back (coppiced or pollarded) when they start to get too big. For a discussion on coppicing and pollarding, see the Blog, January 1st, 2021.

As mentioned in previous Blogs, the walnut tree was a casualty of the April frosts, but there are a few nuts nevertheless, which I collected at the end of the month. There are only enough to last a few weeks, however; in contrast, I have only just finished the walnuts I harvested in the autumn of last year!

September’s weather was mostly dry, sunny and warm, or in other words the drought continued, for the first three weeks, with the temperature even reaching 40° on the 12th! From then on it started to get cooler, and the last week saw some heavy rain showers, and I even lit the woodburner on some evenings. Morning temperatures did get down to 6° on the 19th, but have mostly been around the 10° mark. Until the 24th, we had only had 14mm of rain, but after that the showers began, and we finished the month at 76mm. See the full Monthly Weather Record below.

I decided to enrol on an online course on Ecosystem Restoration this month. It is organised by the UN and other partners in the field, is free, and is dubbed a ‘Massive Open Online Course’! Massive it certainly is, with over 15,000 participants worldwide. It is really aimed at government departments, NGO’s and other organisations which are involved in ecosystem restoration on a national or regional scale, but it is nevertheless interesting and is very well organised. Although we were only in Week 2 of the 8-week course by the end of September, I have already picked up some useful knowledge which can be applied to the situation here. Each weekly module has one or more lessons, some videos, case studies, a workbook where you can apply the week’s materials to your own situation, and a quiz, in which you have to score over 70% to be able to continue. On successful completion of the course, you are awarded a certificate! I hope it’s a massive one.