Just submitted: Gardening with Grasses assignment 3. This time was tasked with creating a planting scheme for a roundabout.
I now have a planting plan I am happy with. The plan is underpinned with a base level of around 30-60cm height around the perimeter of the circular bed, rising to a slightly taller level of around 90cm height for the inner circle. Additionally, a taller still level is included to provide a kind of 'above the parapet' floating dimension (the Alliums and Achillea).
My first pick of grasses was Stipa tenuissima, whose bleached blonde look I love. I can imagine this looking very atmospheric to drivers in its exposed position on the outer edge of the traffic island to be tussled by the wind and motion of the traffic.
The Sporobolus heterolepis I added in as the Summer green tones and Autumn orangey tones, greater bulk and sparkly flower heads give range and depth to the ornamental grass element of the scheme.
Perennials I have picked based on contrast to each other and the chosen grasses, with which I've aimed to provide interest across a late Spring to first frost spectrum. The bulb underplanting is intended to address a potential gap in seasonal interest following the cutting down of the grasses at the end of Winter (likely late Feb time).
The Rosemary islands are intended to carry a deep lustre green throughout the year and particularly in Winter and provide an impactful backdrop to the blonde Stipa ten. It seems good to have a robust vertical consistent form in there against which the globes of the Alliums and umbellifer flower heads of the Achillea and Hylotelephium may rise and fall over the course of the year.