As a landscape architect, I take pleasure in thinking through the meaning, limitations, structure, seasonality, texture, color, and composition of plantings that I work on. My rain garden in our parkway is no exception.
I had a couple of years to think about this and began to formalize my objectives over the winter months:
- Don’t solve problems by throwing money at it. Design by being mindful about resources.
- Rely on native plants that evolved to deal with our natural history and climate and thus provide resilience and longevity.
- Select those native plants that would be suitable for a rain garden environment.
- Develop a composition that could be reproduced in variations in other locations.
- Aim for an end result that communicates care, value, and pride.
- Keep the planting design simple enough so that it could be maintained without the knowledge of a master gardener.
- Break some rules.
Why didn’t I mention color, texture or succession? Well, they are not objectives, they are
Prerequisites. And before I get too far along, let’s quickly talk about the big word: Nature.
I will be using native plants, but I’d like to think that I am humble enough to realize that I will not re-create nature or a prairie ecosystem. I intend to borrow from it and demonstrate how to use our native plants successfully in a horticultural context. But that is as far as I dare to aim.
With this framework in place, I could move on to the next one. Let’s call it the…
To keep the rain garden functioning, I need to maintain the soil’s infiltration capacity – or, even better, improve it. The extensive and fibrous root systems of our native prairie grasses and sedges do just that.
Yet, my parkway doesn’t come close to the vastness of a prairie. And most prairie grasses are tall, which makes them a perfect fit for vast landscapes, but not for my molecular sized rain garden. To achieve a level of proportionality, I will have to rely on a groundcover matrix of sedge species that are smaller, more compact, and a better fit for the space. In this case, I will largely rely on Carex sprengelii (Long-beaked Sedge) and Carex vulpinoidea (Fox Sedge).
The sedges themselves would provide a stunning rain garden for most seasons. Still, I would like to add some structure, texture, contrast, and seasonality.
From color to contrast
Two Baptisa australis (Blue Wild Indigo) that flank the path at the side yard gate will add structure, along with two Amsonia hubrichtii (Blue Star) in the east end and one more at the west end of the parkway landscape. A number of Panicum virgatum ‘Shenandoah’ (Switchgrass) that are spaced between the Baptisia and Amsonia will continue the layering of heights. Yet the upright Panicum will contrast with both, the round shaped Baptisia and Amsonia.
The flowering season is opened with Mertensia virginica (Virginia Bluebells), Geranium maculatum (Wild Geranium) and hybrid Aquilegia (Columbine). May and June would be dominated by the display from the Baptisia. The summer display may vary, because this is where I like to break the rules. Rather than relying on native perennials, I plan on using annuals, which may vary from year to year. This year I will start with a yellow-orange-red collection of hybrid Coreopsis and Dahlia.
Another rule breaker is the addition of two non-native geophytes: Daffodils and purple Alliums.
Autumn will be illuminated by the stunning fall colors of the Amsonia hubrichtii and Panicum virgatum ‘Shenandoah’. To complement the range of golden-red hues, I added Symphyotrichum novae-angliae ‘Purple Dome’ (New England Aster), with its purple flowers and yellow centers. (The purple flowers are actually bracts and the yellow center are the actual flowers).
Native plants have the stigma of delivering a wild and unruly look. That is not surprising considering that a considerable number of homeowners risk cardiac arrest upon the discovery of a clover leave in their lawn.
And this is why color composition, texture, and seasonality are important. They distract – or, even better – re-focus the observer’s attention. They create a new narrative that communicates care and intent, which is a juxtaposition to what is typically perceived as un-tame native plants.
While working with combinations of flower and fall colors is interesting, what really captivates me is textures and contrasts. Yet I can’t take credit for composition, because my inspirations came from stunning scenes I observed in Illinois’ and Wisconsin’s remnant prairies.
One such scene was the contrast between the superbly coarse texture of Silphium terebinthinaceum (Prairie Dock) splattered amongst a sea of delicately fine textured grasses, sedges, or rushes.
A scene that is picture-made for a garden environment, as it can be reproduced even at smaller scales.
The matrix of sedges and solitary Amsonia provide the beautiful yet delicate fine texture that is then interrupted four times by the majestic leaves of the Silphium. And yes, the Silphium has flowers that provide a spectacle on their own – but this is really about the contrast in texture, not the color or towering flowers.
The Silphium continues to draw the eye into the winter season, when its majestic leaves begin to curl and turn gray-brown with white speckles. The Panicum provides a remarkable contrast with its golden-reddish shafts against the pure white snow while the seed pods of the Baptisia with their blackish shell and silvery interior are reminiscent of elegant early 20th century black and white photography.
Committing to a native plant pallet in a design comes with its limitations. And that, as it turns out, can be a good thing. It’s something that keeps driving the creative process. Rather than getting bogged down by what a list of natives doesn’t provide, we begin to discover and explore their unique features and elements, whether it is the eye candy part or the functional element – managing stormwater.