Rock Gardens

• When positioning stones on a slope try to imagine how they would look in their natural state. Avoid symmetry; a careful randomness is a look you desire.
• Arrange each rock, so its best face will show well and then dig it a third to a half into the incline so it looks like an outcropping, not a stone sitting awkwardly on top of the soil.
• Slope the stone back to direct rain towards plant roots.
• Vary the size of the planting pockets between the rocks to accommodate the various mature diameters of your favourite plants and to reinforce the idea of randomness.
• Rock garden plants grow best in well-drained soil. After placing the stones, add a mixture of horticulture sand, vermiculite, and peat moss into the planting pockets.
• Avoid rich soil or clay that won’t drain.
• A sprinkling of lime is recommended in areas with acid-type soils. Two plant exceptions are Lithodora and Gentians that prefer the acidic soil condition.
• If your rock garden is going to be more than 2.5 m (8’) wide, incorporate a path and steps through it so you can maintain plants, weed, and clean up in the fall.

• Make your rock garden look as natural as possible
• Larger stones are preferable. A lot of small rocks can look messy and ineffective.
• Try to work with stone from your area that will harmonize with your architecture and hard landscaping.
• All the rocks should be of the same general kind rather than a geological collection.
• Novelty rocks simply grab too much attention.
• Weathered stone that’s porous is ideal. Limestone, for example, absorbs moisture and acts as a buffer during dry spells.
• Non-porous rocks such as Granite can cause rapid drying of the surrounding soil system because it doesn’t absorb moisture.
• Avoid all soft and scaly rock, shale, and un-weathered sandstone.

• The choice of plant material always depends on lighting conditions
• Proportion is paramount in relation to the size of the rocks or boulders you’re using.
• For large scale landscape rocks with approximately 100 cm (40”) between them, you can work successfully with such slow growing specimens as Rose Daphne, Nest Spruce, Dwarf Alberta Spruce, Boxwood, Little Giant Globe Cedar, Goldmound and Goldflame Spirea, Dwarf Hinoki False Cypress, Jeddeloh Dwarf Hemlock, Blue Star and Goldstar Juniper, Dwarf Mugho Pine, Sunburst Hypericum, Dwarf Balsam Fir, Yellow Gem, and Abbotswood Potentilla.
• Cascading plants like Dwarf Japanese Garden, Blue Chip, Siberian Cypress, Rockspray Cotoneaster, Stephanandra, Wintercreeper Euonymus, and weeping Japanese Maple work well with the above choices
• Mix evergreen with deciduous and vertical with horizontal to create a tapestry of textures worthy of attention all year.
• For a smaller scale use small stones, miniature bulbs, annuals, and perennials to provide flowering interest for many months.
• Start with spring-flowering bulbs such as Snowdrops, Winter Aconites, Glory of the Snow, Crocus, Iris reticulata, Puschkinia, Scilla, Dwarf Daffodils, and Tulips.
• For April to May there are many low-growing perennials that would add bursts of colour like Primula, Basket-of-Gold, Pasqueflower, Candytuft, Rock Cress, Creeping Phlox, Dwarf Iris, and Thrift.
• The next perennials to bloom are Woolly Yarrow, Mt. Atlas Daisy, Bellflowers, Creeping Speedwell, Yellow Ice Plant, Dwarf Dianthus, and Saxifrage.
• For summer you can intersperse annuals that will reliably bloom all summer. Dahlberg and Swan River Daisy, Alyssum, Lobelia, Portulaca, and Nierembergia are easily maintained. Summer flowering perennials include Sun Rose, Coral Bells, St. John’s-Wort, Blue Flax, and Stonecrop.
• For a low mat effect, plant Creeping Thyme or Scotch and Irish Moss.
• For interesting foliage colour try Silver Mound or Silver Brocade Artemisia, bright yellow Creeping Jenny, steel blue Donkey-tail Spurge, Stonecrop, or Elijah Blue Fescue.

• “Rock Garden” and “Alpine” plants are used interchangeably but a true Alpine grows above the tree line in mountainous regions.
• Alpine perennials have a dwarf habit, bloom profusely, and prefer a well-drained, gritty soil. These include Gentians, Saxifrage, Alpine Lady’s Mantle, Stonecrop, Alpine Columbine, Lewisia, Alpine Poppy, Arctic Campion, and Alpine Aster.

If you have limited space you can create a miniature rock garden in a special planting container called a trough. They are similar to a window box planter but shallow and made of concrete.

• A trough is a heavy rectangular tray with drainage holes that’s elevated on concrete blocks and filled with a layer of stone at the bottom and quick-draining, gritty soil.
• A standard soil mix for a trough is 20% compost, 30% loam, and 50% fine gravel/sand.
• In a smaller trough, you can try planting succulent perennials like Stonecrops, Hens and Chicks, and Saxifrage with interesting rocks and gravel to finish the top.
• Very slow-growing evergreens can be used in larger troughs. Once planted keep the trough free of weeds and water as needed (every day or every other day in hot weather).
• Troughs with winter hardy plants can stay where they are or be set on the ground in December and covered with evergreen boughs.