You may have a gentle slope or uneven area in your yard that could be a rockery using some good size boulders and then rocks for the base with smaller ones for creating plant pockets. The highest area can be on the back or one side to create the illusion of even more height. Place taller plants there to help shelter the smaller plants from wind and sun. Add a short wall with brick or flagstone as well as places to step or informal paths in between to allow easy weeding and maintenance. Build your crevices and plant pockets with the smaller pieces of field stones to form outcropping and low areas, then fill with soil and compost to plant. All this can be planned out on paper ahead of time so you have a good idea of how much rock you will need, how many plants to buy and where they will go. Plant small bulbs like these mini allium. They are available with purple, white or yellow blooms. Most are finished blooming before the perennials and die back to disappear when finished.
You can plant a few and add to the rockery in between perennial plants over time. You may want a few low growing shrubs as well so buy and plant them first. They can be purchased in fall or on sale at the end of the season but don’t plant later than the end of September so they have time to become rooted well before winter. Creeping plants are great on the edge of walls and slopes if allowed to hang over to create a ground cover of blooms. SPRING: Don’t forget to plant a few spring bulbs in the fall, placed in between the late spring and summer perennials. They will add lots of colours to the garden early before anything else is emerging from the ground. Try mini tulips, crocus, grape hyacinth. Perennials for spring blooms include primrose, pulmonaria and rock cress.
EARLY SUMMER: Columbine, candytuft, thrift, bleeding heart, bellflower, lily of the valley, coral bells and Shasta Daisy will bloom in late May and early June.
Mid to LATE SUMMER: Day lily, liatris, giant iris, Ajuga, lambs ears, thyme, artemisia, ornamental grass, black eye susan, sedum, Lady's Mantle and chrysanthemums all do well in rock gardens with mostly sunny locations. They are also drought tolerant plants once they become established in a rockery, need little care and water and don’t require special soil.
Many low growing herbs like creeping thyme, creeping phlox and chives look great in crevices and pockets. Hens and chicks and low growing creeping sedum spread and root on the ground where their stems touch but are easy to control if trimmed back each spring. Use good top soil, compost with peat moss and manure when you start planting. This will allow the plants a good base soil to root in and become self sufficient for many years. Replenish with a top dressing of manure or compost every few years.
For winter protection from wind, freezing and thawing, simply leave some of the foliage to provide cover for the plants and clean up the dry stems and leaves in spring. Tender shrubs can be wrapped in burlap and roses need to be covered or collared with leaves to help with winters harmful wind and cold. Plant bulbs in October and see how much interest and color they add to your garden. Most spring bulbs die back when they are finished blooming at the end of May to make room for the perennials. Oxalis, Scilla, snowdrops and crocus all emerge as soon as the snow melts and do well in rock gardens. Mini tulips like “Tarda” are bright yellow and grow to 3 or 4 inches high. They have large 2 inch blooms and will multiply over time so you can dig some up and plant them all through the garden. Hyacinth and Daffodils also come in short mini varieties for a rockery.
