Hello, I have a short south facing slope at the start of my front yard where it meets the sidewalk, with two large old silver maples at either side. It is about 30 feet long and 4 feet wide [with 3 standard steps from sidewalk to the top of the slope]. The area currently has poor grass and weed cover and is impossible to mow. Once the tree canopy develops in spring, it gets almost no direct sunlight, though it is bright under the trees. It is also dry and usually only gets water when it rains. I would like to build a low maintenance, drought tolerant rockery here and would appreciate any advice. I understand I am asking a lot from the site. The neighbouring gardens mostly have Vinca minor [periwinkle] on their slopes and I was hoping to create a bit more variety in a rockery. Thank you.
Dear Gardener, thank you for asking an interesting question about developing a rock garden in a shady, dry area.
Step one will be to introduce some new soil amendments to the area. Your silver maples have been depleting your soil for many years (with the result that you have poor grass and weeds). Adding some organic matter is essential. May I suggest a 3″ layer of well-composted organic matter like manure or leaf compost, and later in the summer, especially if it is dry, adding a layer of shredded cedar or pine bark mulch.
There are plants that are appropriate for your rock garden’s criteria of being semi-shade and drought-tolerant. For a rock garden, select the plants that do not grow higher than about a foot, and consider your colour scheme and having plants that flower throughout the gardening season.
To get you started, here is a list of plants to get you started on establishing your rock garden:
Plants for rock gardens
Rock cress (Aubretia deltoidea)
Creeping sedum (Sedum divergens)
Hens and chicks (Sedum tectorum)
Creeping thyme (Thymus praecox)
Woolly thyme (Thymus pseudolanuginosus)
Irish Moss (Sagina subulata)
For some other suggestions, click here
The Ontario Invasive Plants Council has also published a useful booklet you might want to explore:
May 6, 2021