Rock Garden Rock Stars: Perennials that Spill or Cascade

creeping phlox - rock garden

Cascading perennials are valuable assets to any garden, but if you have a rock garden, acquiring some of these varieties is a must!

7 Favorite Perennials for the Western Rock Garden

Most of these are the tough, small rock garden or alpine plants that are cold-hardy, low-maintenance and often evergreen. Their foliages are uniquely attractive for some are silver or burgundy-colored while others have masses of waxy leaves that are drought-tolerant. Here are a few samples of perennials that spill over rock walls or container plantings that will enhance any rock wall or rock garden.

aurina basket of gold - rock garden perennials
Aurina or Basket of Gold

1. Aurina or Basket-of-Gold

The brilliant gold colors of Basket-of-Gold set spring gardens glowing. Aurina is cold hardy, drought tolerant and enjoys every nuisance of living in rocky Mountain gardens. Its soft, silvery foliage stays nice all season after the spent flowers are removed. Aurina has the very important job of providing early food for beneficial insects like lacewings. The beneficial insects will lay their eggs over the larva of pest insects like aphids and when the eggs hatch they will devour the aphid larva.

creeping phlox - rock garden
Creeping Phlox

2. Creeping Phlox

Creeping phlox brings soft pastel colors to the spring garden. To keep Creeping phlox’s foliage attractive, never trim it until it finishes blooming then trim the entire plant down to a tuft. The phlox will grow all summer and will be thick and full in preparation for next season’s blooming.

cerastium snow in summer - rock garden perennials
Cerastium or Snow in Summer

3. Cerastium or snow-in-summer

Cerastium is so hardy it is often considered a zone-two perennial and it is simple to grow as long as it is not over-watered. In May, the luminescent foliage sets wiry stems that will be covered with white snowflake-looking blooms. Thus its common name, snow-in-summer.

soapwort - rock garden
Saponaria or Soapwort

4. Saponaria or Soapwort

Soapwort is very popular in western rock gardens for it blooms in late spring, a gardener’s favorite outdoor time. The dark tiny-leafed foliage is also very attractive and will stay evergreen under a winter’s blanket of snow. Soapwort is easy to seed by simply trimming off the spent ends of the blooms and spreading them along the wall or any other spot where this gorgeous perennial can spill.

druetts variegated - rock garden
Druetts Variegated

5. Druett’s Variegated

Druett’s is an outstanding perennial that is underused in Rocky Mountain gardens, mainly due to lack of availability. Its tiny balloon-shaped buds open white over a creamy-edged rosette from May to September without any type of maintenance from the gardener.

callirhoe winecups - rock garden perennials
Callirhoe – Winecups

6. Callirhoe or Winecups

Native to the grasslands and prairies of North America, Winecups begin their unending blooming in mid-June and keep blooming to the end of the season. Winecups are identified as a hardy zone-four but this plant has winter-killed in my Bear Lake garden. It but always survives in my Utah gardens, however. The white centered wine flowers and green lacy foliage are lovely when decorating a rock wall.

potentilla nepalensis - rock garden
Potentilla Nepalensis

7. Potentilla nepalensis

Potentilla furnishes long runners that wind in and around other perennials and also cascade over walls. Potentilla starts blooming in early summer in dynamic colors of salmon and reds with dark contrasting centers.

These are only a few of the perennials that spill gracefully over walls or containers. Others like the small early blooming Veronicas and the dependable short Sedums create a delight in the garden. Evening primroses and the deltoid type of dianthus are also great rock-softening perennials. For a colorful palette and ease of care, add these fine perennials to your rock garden areas.

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