Rock gardens can be miniature beauties or an entire yard full of blooming and changing plants. Annuals are natures delight in the sense that they bloom their hearts out. There best feature is after blooming they produce tons of seeds and next year, the same annuals may return to your yard. One of the reasons to use an annual in your rock garden is to provide that lush growth of flowers to augment the starkness of rock and sand, the two primary components of a rock garden. In the Northwest, our rock gardens tend to be the places with the worst soil and lots of rocks. Which annuals should you use to decorate these tough to grow in spots in your yard?
Sunflowers Galore
If you drive through the midwest, you'll see clusters of sunflowers, often grown from hybrid plants used as a crop. If you've never grown sunflowers, you will find them easy to grow, so easy children love to grow them. There's a number of varieties that range in color and size and you can get the native species that has many branches and lots of flowers.
Calendula
This plant is half-Sunflower and half-Marigold in my mind. It has large, tough seeds that are the easiest to grow that I've encountered. These seeds have grown in my cedar chips. They bloom and bloom. It's tough and hardy and a real delight. The come in gold, creamy yellow, slightly reddish, somewhat orange, all from the same set of seeds.
Candy Tuft, Alyssum and Gold-Dust Alyssum
Many people confuse candy tuft and alyssum because they are very similar in that they produce tons of white and sometimes purple shaded flowers and bloom almost continually. Many times they both act like perennials since they are really tough. These don't grow very tall and spread. Gold dust alyssum is similar to alyssum but it often hangs by one root from a rocky crag and produces a much taller and wider plant with brilliantly yellow flowers. The gold dust alyssum doesn't bloom as long but it is a real standout. Candy tuft tends to have flatter bunches of flowers whereas alyssum produces tufts. All work well in a rock garden.
California Poppies
Not all poppies have the same growth pattern, many oriental poppies are perennials rather than annuals. California poppies grow easily from seed and have a wildflower growth pattern well suited to rock gardens. California poppies have hardy greens and cup shaped orange flowers that keep blooming.
Ice Plant
This desert native looks quite a bit like a cactus when you look at the creeping stems in that it is rather fleshy. The flowers seem to appear out of nowhere in brilliant pinks and yellows.
Chamomile and other Herbs
Chamomile is commonly found in the sandiest, driest soils growing a bit stunted but happy. In a garden, chamomile looks like a daisy with a bit of a heavier flower with that well known sweet scent. Oregano, marjoram and thyme also like a sandy dry hot environment.
Love-in-a-Mist or Nigella
This plant is extremely hardy and the seeds are almost as attractive as the somewhat hairy blue flowers. The seed pods are about an inch around but more oval. Use the seed pods to sow them around your garden.
Miniature Hollyhock, Mallow and Fennel
All of these plants have a tap root that is grown from seed, many times growing quite deep and making it nearly impossible to remove from your garden. I love fennel because it attracts tons of pollinators and birds to my gardens. Mallow and miniature hollyhock grow tall and wide with pleasing pink and purple and white flowers.
How are annuals used in a rock garden? Use them to fill in cracks in rocks or scatter them lightly over a raked sandy area. The key to using them in a rock garden is to have them appear naturally strewn in and around your rocks. Open space is as needed as the blooms and many times the rocks themselves are the stars of the garden. But just because your rock garden is hot and dry, it doesn't mean you have to forgo flowers.