I have a space approx 12 ft x 4 ft. It has a wooden wall (separating it from the driveway along one long edge, a short concrete wall (15 inches high) on the other long edge and the house along one short end. The other short edge is on a small concrete path. Because of the driveway, there are pebbles in the soil (they come from the driveway). It would be next to impossible to add much earth because it would wash away onto the concrete path. Therefore the soil is poor and shallow . There is quite a bit of sun. I am wondering if I could put a Kerria bush near the house and fill the rest with hosta. Would this be a suitable plan, or can you suggest a better one.
Thank you for your description for this challenging gardening spot!
You could try the kerria if you wish but it prefers light shade, partial shade or full shade and soil of average fertility that is well drained. It may well survive but you may get fewer flowers in these conditions. With regards to the Plantain lily (Hosta), although they are known as wonderful woodland plants, you could try some in this sunnier spot. Some will tolerate full sun although morning sun is preferable to afternoon sun. Hostas do like fertile, moist and well drained soil though.
The good news is there are lots of plants that can not only survive but thrive in sunny spots with poor and shallow soil. One such is shrubby cinquefoil (Potentilla); you can select dwarf varieties that can live in rock gardens (and other rock garden plants would be a good category to look at) and taller forms to provide some height. Both are adaptable shrubs that will thrive in almost any conditions – they prefer full sun but will tolerate partial or light shade. The soil should preferably be of poor to average fertility and well drained. On mature plants, prune up to one-third of the old wood each year to keep the growth neat and vigorous. These plants look best if left to grow as informal mounds and rounded shrubs.
For an evergreen option you could look at the junipers (Juniperus), such as creeping juniper. In the herb/ground cover category thyme (Thymus) and hens and chicks (Sempervivum) could be options.
Other types of plants to look at when visiting a garden centre are the native plants. If you are in the Toronto area a good location to visit would be the Toronto Botanical Garden, 777 Lawrence Ave East (www.torontobotanicalgarden.ca) where you can see these and other plants growing in beds that have very similar conditions to yours.
Regardless of what you plant do add some top dressing of mulch to help preserve the nutrients and moisture in the soil as well as suppress weeds.
I hope this provides you with some useful idea, enjoy the planning and planting!