Sally Mackenzie and her family moved into a 1980’s small bungalow in north east Scotland almost four years ago with a garden size of approximately 250m2. The garden was mainly laid to lawn with perennial shrubs and a very neat privet hedge bordering it. Gardening at an altitude of 200m, fairly fresh winter winds and frosty days are normal in the garden. We asked Sally to talk us through what what was important to her in using one of most abundance resources we have in Scotland, to create a rain garden.
“I’m an ecologist so very aware of the impacts of climate change and can often feel overwhelmed by the enormity of what that it will mean for all of us, and the species we share the earth with.
“I recently read that in the UK gardens make up around 780,000ha which is the combined size of Aberdeenshire, Moray and Fife. That’s enormous capacity for gardeners to work together to help mitigate for climate change by providing habitat networks for species; by planting more flowers for pollinators; by using water to create wildlife habitat, or by growing more of our own veg from home-made compost.
The Beginning of Our Garden
“The first thing we did was let the privet hedge grow and flower. We planted a native species hedge along the back boundary of hawthorn, Guelder-rose, elder, and alder and started adding more flowers, especially poppies which I love, into the shrub borders.
“The next real opportunity for change came in 2019 when, with the help of my builder dad, we started putting on an extension to our house.
Pond and Rain Garden
“All new developments are required to have a sustainable drainage system (SuDs), to reduce the speed at which water flows off roads, paved areas, and roofs into drains, burns, and rivers.
“Part of my job role is to comment on the ecological value of planning applications, and all too often we see plastic crates as underground water storage solutions: this was my opportunity to show how water can be used creatively to make wildlife habitat, and reduce the impacts of heavy rain storms or snow melt.
“I designed a pond and rain garden system to pipe all the water coming from our house roof through drainpipes to the pond which is 7m2. From there, an overflow takes excess water to the rain garden.
“The pond is lined as we have really free draining soil. I’ve planted it with a range of mostly native pond plants with shallow sloping edges lined with wood, stones, and overhanging plants to provide wildlife habitat.
“It’s been in a year and it is just a delight as birds come for a bath, there is a croaking frog, and a common hawker dragonfly has lain her eggs.
“When we have nice sunny days the pond level naturally goes down due to evaporation, and a heavy rain storm will fill it back up quite quickly, with the overflow leading to the rain garden.
“I made this myself, using calculations from the Building Regs Manual to size it. I removed the top layer of grass and topsoil to reach the stony sandy sub-soil, and edged it using repurposed stone cobbles. It is planted with a mix of plants that we already had like geraniums, hosta, yellow flag iris, and crocosmia, providing colour from spring until autumn.
“The rain garden has a small stone filled soakaway which hasn’t been needed as even after the heaviest snow melt, the rain garden has filled, and naturally drained after a few hours – it is such a delight to see the water flow through the pipes.
“I’m hoping that the rain garden will provide a nice, shady damp extension to the pond for amphibians and insects to hang out. To help them along I’ve created two hibernaculam at the edges of the pond using leftover pipe, stones, and wood from our building. I love the fact that our roof water is creating this wonderful habitat, and that we’re helping play our part in reducing run-off downstream!
“We had to excavate a lot of ground to create the extension foundations and that gave us another opportunity in soil, top soil, and more nutrient poor sub-soil. While my husband was bemoaning the loss of his grass, I saw opportunity to get creative in the garden!
“I spread the subsoil pile over a 10m2 area of grass to a depth of 20-30cm and planted a mix of annual cornfield species, and a perennial bee, bird, and butterfly wildflower mix. The first year was a riot of red poppies, blue cornflowers, yellow corn marigold, and white corn chamomile, but this summer the perennials came through starting with pink and white campions, teasel, tansy, musk mallow, and viper’s bugloss.
“I often see the flowers full of bees and hoverflies, and was really excited when I found the caterpillar of the Campion Moth inside a white campion seed head, and a few days later caught the adult moth in my moth trap…it is working, the pollinators are coming.
“I’ve let the cornfield annuals and poppies self-seed all over the garden, and added in a few extra plants for pollinators that I’ve grown from seed or received from friends including Salvia viridis ‘Blue Monday’ which I planted in swathes alongside a garden path, and common chicory with its lovely blue edible flowers that close at night.
“I was still left with a large pile of relatively fertile soil so I used this to create mixed flower and veg beds, and a herb garden close to the back door.
“Like many folk I’ve been working from home and after far too many zoom meetings I’ve loved going out into the garden to weed, move earth, or just stand and watch the birds and think about what I’ll do next.”