Night of the Living Mulch
So a little while back I came across this 2017 Washington Post article about using sedges (Carex) as a substitute for mulch.
It’s a variation of an idea pioneered by Piet Oudolf and other naturalistic designers of perennial gardens: use dense, shorter, less showy plants as a foundation or matrix to fill in around those that are taller and more colorful. It serves the same function as mulch: suppressing weeds, keeping the soil moist and cool, and adding organic matter. But it can also give gardens a meadow-like fullness, providing a calm background to the most exciting plants.
Anyway, this article got me thinking.
I love how this approach has been adapted in places like Chicago’s Lurie Garden. And I agree that it is better to cover your ground with plants than with mulch. But I haven’t embraced either the matrix or sedge-as-mulch idea in my own garden.
The whole matrix approach is perhaps better suited to larger spaces than my 1/4 acre suburban lot. Also, I am a color addict. I just need masses of it, and every year I seem to need a bigger fix.
I do cover much of the ground with dense, shorter plants – but not grassy ones – especially along the front of the beds and borders. For example: Catmint (Nepeta) and Wild Geranium (Geranium maculatum). But perhaps this is just a traditional use of plants as groundcover.
For us, grasses are more like specimen plants, like Switchgrass (Panicum virgatum).
But more often, the ground is dominated by taller plants. By early summer, they have blocked any view of the ground – but if you peak under the leaves, you can see the ground is still bare.
One problem we have is that in spring, some of the beds have bald patches. I may deal with this problem by letting the Celandine Poppy (Stylophorum diphyllum) simply take over certain areas. One problem with Celandine Poppy, though, is that by mid-summer it tends to develop a fungal disease that disfigures and then kills the leaves. However, by then the taller plants will have taken over.
Anyway, you may want to read the article. It has a lot of information on sedges that I don’t really talk about.