The Rock Garden is the perfect solution for those people who have a steep slope of land, possibly rocky and invariably fast draining thanks to the force of gravity and no doubt containing soil of poor quality. While the Rockery, as the rock garden is at times called, is often planted with a variety of small trees, shrubs and perennials all of which can tolerate all these conditions there are ways to incorporate annuals as well or even plant a rockery entirely using only annuals.
Of course, these annuals must have a certain tenacity. They have to be tough to survive in poor, dry, rocky, slightly alkaline soil, in an exposed and likely windy place and if these plants tend to self-sow, all the better. Being on a steep slope, they need to take care of themselves. No one is going to be climbing up that hillside very often to hold their hands, now are they?
With all this in mind here is a list of the annuals likely to make even the most barren of terrains look a pretty, colorful sight.
California Poppy (Eschscholzia californica)- Sow seeds where you want them as these pretty little 2 inch wide single or semi-double flowers have delicate roots which hate to be disturbed. They self-sow readily but you’ll have to share them with the birds who love to nibble on the seeds.
Pot Marigold (Calendula)- These 2-4 inch wide flowers come in vibrantly sunshiny colors ranging from palest yellow to deepest orange. Blossoms can be single and double and the smaller cultivars “Fiesta” “Bob Bon” and “Dwarf Gem” all coming in under 15 inches tall are perfect in the rockery.
Bachelor’s Buttons (Centaurea Cyanus) - Cornflower blue is the preferred color for this pretty wildflower-turned- garden-favorite but they also come in shades of burgundy, pink, white and rose. Plants grow from 1 to 2 feet tall, have narrow 2-3 inch long, green-gray tinged leaves and flowers are 1 -2 inches across. Self-sowing is their claim to fame but they are also known for their acceptance of near drought conditions and the usually alkaline soil often found in Rockeries.
Johnny-Jump-Up (Viola Tricolor) - This tiny version of the Pansy with vivid purple and yellow grinning faces seem to add a joyous feeling to any garden but can do particularly well as a ground cover amongst rocks and other taller plants on a steep slope. Johnny-Jump-up grows 6-12 inches tall and self-sows at will.
Sweet Alyssum (Lobularia maritima)- This trailing plant looks like a low-hanging cloud when in bloom. It has the tiniest four petaled flowers in clusters all emitting a sweet, honey type fragrance. Bees and butterflies love it as do gardeners for erosion control. Colors range from pure white, pinks, lavenders to violets. Sizes range by cultivar from 2 inches tall to a foot high.
Forget-Me-Not (Myosotis sylvatica)- Coming in between 6-12 inches tall, Forget-Me-Nots spread well to fill in crevices and brighten any lonely spot with their profuse blooming, small, cheery, true blue flowers. They do require a bit more water but are well worth the trouble of adding a bit of compost in their planting sight to keep them happily coming back every year.
Creeping Zinnia (Sanvitalia Procumbens)- Not a true Zinnia but resembling them, this plant looks great cascading down a hill covering it with 1 inch wide flowers in brilliant yellows and oranges all with dark brown or purple centers. Blooms from mid-summer to frost and the seeds need to be planted where you want them as they hate transplanting. Great for hanging baskets and tumbling over retaining walls, too.
Moss Rose (Portulaca Grandiflora)- Coming in the widest array of bright and pastel colors imaginable, this plant grows 6 inches high and a bit over a foot across. The leaves are fleshy, the trailing stems have a reddish tinge and the 1 inch flowers resemble tiny lustrous roses, single and double forms. Loves the heat and drought is no problem. Self-sows readily.
Nasturtium (Tropaeolium Majus)- These come in two type both of which are perfect for the Rock Garden. The climbing or trailing variety grows to 6 feet long and the dwarf variety grows in a 15 inch high round mound. Both have the distinctive round and heavily veined, bright green leaves and the deep-throated flowers slightly over 2 inches wide come in delicate pastels as well as vibrant reds, pinks, yellows and pure white. Bees and Hummingbirds love these and people often like the leaves and flowers for their watercress taste in salads.
With these tough little annuals an unsightly bunch of rocks on a sloping area can be magically and beautiful transformed in a lovely Rock Garden. So, what are you waiting for?