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Cornucopia - My bog garden

My bog garden
Rupert Wade

Right plant, right place is an excellent maxim for all gardeners, helping to avoid plants failing to thrive, or worse still, die. However when you garden on top of a 100 foot high hill of sand you do hanker after being able to grow moisture lovers such as primulas, rodgersias, ligularias and cimicifugas etc.

The answer to my dreams came during a talk by Kevin Hughes to the HPS Mini Group in 2007 on Bog Plants. As part of his talk he explained that the popular idea of digging a hole, lining it with old compost bags or sheets of polythene, then puncturing it for drainage just does not work. Every tree and shrub root in the area makes a beeline for the moisture entering the boggy area through the puncture holes, rapidly congesting it.

The solution he proposed had been developed by two people in the US. In brief, a 12” deep sump provides a reservoir of moisture, and a 12” deep raised bed provides a drained medium in which to grow moisture loving plants. The retaining walls can be made from whatever materials you have to hand. Water falling on the area is stored in the sump, excess water drains through the gap between the top and bottom liners at ground level. As the plants grow and use moisture from the compost, air and oxygen are drawn into the compost in place of moisture, keeping the compost sweet. Hey presto! ideal growing conditions and the answer to my dreams.

In early 2008 I revamped my pond and as part of my updated Yellow Book entry for 2009 I stated, rashly with hindsight, “new bog garden next to revamped pond”. With nine months before the first opening there was plenty of time to get the work done, or so I thought. Late 2008 and early 2009 saw continual heavy rain, hard frosts and of course snow so any construction proved impossible. March and early April were occupied catching up with the backlog of winter and spring maintenance. Construction finally started on 18 April, six weeks before the garden was due to open for the Yellow Book!

Over the next fortnight the hole was excavated, being able to pile the soil alongside the hole saved a considerable amount of time and effort. All of the family made the same comment on finding out what I was doing, “What about the dogs? They will get their feet muddy and bring it into the house.” I reassured them that the surface would not be muddy. I hoped that I was right otherwise I would never hear the last of it. Then Alan, our daughter Becky’s partner went a stage further and declared that the “fat one” would sink into the mud, referring to Bonny our Cocker Spaniel who was a little overweight at the time.

The completed hole was measured, the liner ordered and fitted without any problem. A dwarf wall was built where the ground sloped away from the pond to bring the edge of the bog level with the edge of the pond. I thought the pointing of crazy paving would be a breeze, in the event it took eight hours. Oh my aching back!

All the soil that had been dug out was mixed with well rotted compost before returning it to the hole. This resulted in a heap about a foot above the level of the path. The whole thing was left for a few weeks whilst the soil settled under its own weight. I didn’t want to tread the soil down for fear of squeezing out all the air.

A few days before the garden opening I raked the surface, which by this time has settled to just above path level. At long last the plants were laid out in their pots just in time for the garden opening. Planting took place on Sunday 31 May, mostly from pots, however a couple of Iris sibirica were dug up from the vegetable garden in full bloom. Despite the shock, flowering continued unabated after dousing with a bucket of water. Planting coincided with six weeks with very little rain, coupled with baking sunshine. Other than an initial watering the plants were left to themselves as I wanted them to get their roots down to find their own moisture.

The plants flourished, Rodgersia pinnata 'Maurice Mason' (recommended by Fergus Garret) and R. 'Irish Bronze' remained unscorched and in good condition. Primula vialii flowered continuously until the end of September.

A note on watering: the pond is fed with water from the roof of the house when it rains. The soft rain water keeps the pond nice and clear, any overflow runs into the bog garden keeping it topped up. Excess water escapes through the gap between the liners at ground level.

As I write this area is a mix of rusty brown foliage protruding above ½” of snow. I remain full of optimism for spring and better times ahead.

First published in the Wilts & Avon Group Newsletter, March 2010
and subsequently in Cornucopia Issue 28.
© Copyright for this article: Rupert Wade

This article was taken from a copy of Cornucopia that was published in 2011. You could be reading these articles as they are published to a national audience, by subscribing to Cornucopia.


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