BLESSINGS IN BLOOM: Rock-tober Gardens

By Kerry Peetz

It’s October, and our Colorado weather will soon chase away our flower-filled gardens. The temperatures will freeze our vegetable plots and make them a distant memory. Now is a good time to start planning for next season. Rock gardens are a great choice that can be a mix of plants, flowers and rocks that seconds as a work of art.

A rock garden is defined as an outcropping of rocks into which a careful selection of low-growing perennials, annuals, bulbs and shrubs are nestled.

God’s green earth is best at providing rock gardeners with a world of wondrous examples.  For inspiration, in our diocese, we can observe natural rocky terrains on almost every mountain drive. We can also visit man-made rock gardens like those at the Denver Botanic gardens. If a rock garden sounds like something interesting here are a few guidelines to think about.

Rock gardens can be expansive or as small as a few square feet. They are effective if built on a natural slope or terrace. Sloping sites because the angle emulates mountainous regions. You also can construct a rock garden on level ground in an area that receives ample sunlight. Any turf you remove can be used as a handy base to elevate the grade, but add plenty of coarse stones to provide a well-drained base on which to place a sandy soil mix and the featured rocks. Berms - raising rock gardens above flat ground improves privacy, adds interest and creates paths. A crevice garden is a type of rock garden where most of the surface is composed of closely set stones. Originally designed more for plants favorable to high alpine zones. 

Generally speaking, it’s best to place the largest rocks within the soil base towards the bottom of the slope. Use rocks of one geological type. A common rock in Colorado is native granite covered with lichens (moss rock). Rocks are available from landscape contractors and rock dealers. An effective rock garden should have several large rocks, some weighing 200 pounds or more.

Place all rocks on their broadest side and bury them at least one-third to half-way into the finished grade. Arrange them in a natural way, following the grain of the rock. Position rocks to control soil erosion between rocks and to allow soil pockets of various sizes for plants. Use smaller, similar rock as a mulch. Place lichen-covered rock to expose as much of the lichen as possible

Rocks provide many different niches into which carefully selected plants can grow. Good drainage is a must and remember the garden should not be larger than can be easily maintained. Rock gardens can have high maintenance requirements. Weed control is the biggest problem. Most rock garden plants need low to moderate watering amounts and frequency.

Plant a variety of species, repeating some species several times to make the garden look natural. Ideally, rock garden plants should spread slowly. Be careful not to overplant.

Many types of plants are suitable for rock gardens. Generally, plants that are low growing and have a clumping habit are preferred. Perennial plants are most common in rock gardens, although some annuals can be used. Some plants to consider are basket-of-gold, dwarf iris, creeping penstemon, moss pink or creeping phlox, rock soapwort, gold moss stonecrop, hen and chicks, lemon thyme, wooly thyme, creeping speedwell, candy tuft and ice plant.

Having a rock garden with a bench nearby is an attractive addition to any garden. Choosing rocks can be fun and the bench is a perfect place to pray the rosary.

“Jesus is my rock. My rock, my sword and shield. And He’s my wheel in the middle of a wheel. He guides my footsteps and wipes away all my tears. Jesus is my rock, my rock, my sword and shield.” — Lyrics by Gerald Thompson.