Inspirational Ideas for Designing a Rain Garden

A rain garden can be a wonderful feature to include in an eco-friendly garden. Recently, I created customized rain garden planting plans for my clients across the United States and in the United Kingdom. While these may not be the perfect plans for your own specific area, they may provide some inspiration for you as you create your own design. 

But first, what is it? Rain gardens are landscape features with attendant planting schemes which are used as natural bio-filters for the rainwater from a roof, driveways, or other build elements of a property. They are designed specifically for particular sites, and usually include a wide range of plants—a high proportion of native plants—placed in a basin in the ground in which rainwater collects. They are often connected to rainwater harvesting systems or drainage ditches, which direct the rainwater to their location. The idea is that water collects in a rain garden, and is slowly filtered through the soil and plants. 

Not only does this mean that water remains on the property, benefiting plant life and biodiversity, but it also means polluted run-off does not drain away and cause a problem in waterways and the ocean. Rain gardens are a great choice for wise water management in your garden and are an ideal low-maintenance option for busy gardeners. 

Here are more details about three unique projects I have planned:

Kansas Rain Garden 

For a small rain garden for a Kansas property, I recommended the moist basin area be planted up with Carex muskingumensis and Asclepias incarnata. Around these, on the side slopes, I recommended Echinacea purpurea and Penstemon digitalis. And around the drier edges of the rain garden, I suggested Schizachyrium scoparium, Liatris ssp., and a few varieties of Phlox. 

This native plant rain garden design was placed within a broader garden scheme, with many more native plants, close to food-producing zones where the pollinators attracted by this rain garden will be beneficial for fruit production. It was designed to collect rainwater from just one roof section of the home. (Other rainwater was directed to other parts of the design.)

This rain garden was a curving, organic shape designed to integrate in a flowing way with other parts of the design. 

Washington Rain Garden

A recent rain garden I designed in Washington state was interesting because it was partly in full sun and partly in shade. This involved using plants which could handle the deluge in winter, and summer drought, in both the shaded and sunny parts of the rain garden. 

Key plants for the basin were Pacific ninebark, Douglas Spiraea, Cornus sericea, Juncus acuminatus, Juncus ensifolius, Slough sedge and Scirpus microcarpus in full sun. And in the shaded portion: Rubus spectabilis, Lonicera involucata, Blechnum spicant, and Viola glabela. 

For the slopes of the rain garden, I included Symphoricarpos albus, Amelanchier alnifolia, Camassia quamash, Aquilegia ssp, and Asters. 

And around the edges in the sun, Ribes sanguineum, Erigerons, and Helianthemum nummularium, with Mahonia aquifolium in the more shaded location. 

This large, kidney-shaped rain garden was designed to catch rainwater from the roof of the home, and a barn structure nearby. 

England Rain Garden

Another rain garden that I have worked on was for a city garden in the south of England. In this design, plants were chosen to blend well with the surrounding cottage garden design and included some native species along with some appropriate non-native plants.

I suggested a crab apple, Sambucus nigra, Rosa rugosa, Viburnum opulus, Cornus sanguinea, ajuga reptans, campanula, Juncus effusus, Carex pendula, Geranium 'Rozanne', Bergenia and hostas, with the perimeter berm planted with a native perennial meadow mix.

One interesting thing about this design was that it was created in a relatively small, square front garden area, alongside a driveway, to collect rainwater that was flowing from the drive into municipal drainage. Showing that you do not have to have a large garden to think about rainwater management where you live. 

Of course, rain garden design is not just about the plants. There are many other things to consider: location, shape, size, infiltration rate, etc. These specifics, as well as the details of the planting, will differ considerably depending on where you live. So it is important to make sure that a rain garden is designed specifically for a particular location. 

The above designs are not meant to be prescriptive and were, of course, worked out for specific reasons in specific gardens. But thinking about the plants they contain should give you at the very least an idea of how beautiful and useful rain gardens can be.