Cascading Perennials

All great gardens include a good bit of hardscaping, in fact, your urban garden probably has hardscaping features that you don’t even think of as features.

Most houses in Portland are raised above street level, so what happens between foundation level and street level? A rocky slope? A rock or concrete retaining wall?

Cascading Perennials

What about the edges of the driveway, is the ground around them higher or lower? Would it look better with some flowers spilling onto it? The following are plants for softening the transitions from hardscape to garden, which will go a long way toward making a house and yard look like a home and garden.

Featured Plants


Aubrieta: Rock Cress

What’s that long, luxurious cascade of color so covered in flowers that there are no leaves to be found? It’s Aubrieta of course. The Axcent™ series of Aubrieta comes in rich, saturated purples and pinks that do an excellent job of softening hardscaping and trailing over walls.

They bloom March through April in full sun and average soil. These deciduous plants grow 4-6” tall and trail 14-18” long.

Cold hardy to zone 3

Phlox subulata: Creeping Phlox

The hillsides in the Gorge and through-out the Cascades are covered with pastel blankets of color from our three native species of creeping phlox. Garden varieties of creeping phlox are gentle evergreen spilling perennials that flower in pinks, light blue, lavender and white.

They grow 2-4” high and trail 12-20” long in full to part sun, well-drained soil and regular water to establish plants.

Cold hardy down to zone 3.

Iberis sempervirens: Candy Tuft

Some years the crisp white flowers of candy tuft start as early as February! The clusters of pure white flowers bloom well into May and the leaves are evergreen! They thrive in full to part sun and well-drained soil.

Hardy to zone 3. Iberis sempervirens ‘Purity’ is the most common growing 10” tall and spilling up to 24” over time. Iberis ‘Little Gem’ is compact growing 6” tall and spilling 12-18” long. Cold hardy to zone 3.

Read about more varieties and care on our Iberis Feature Page.

Special Considerations:

This combination will fill 4-5’ across a wall. If you have a lot of space to cover, consider repeating these 3 plants over and over, or planting them in large groups of each one. Also, these 3 together will make a spectacular floral show in spring, but for season long interest, consider later-blooming additions such as Parahebe olsenii, Origanum ‘Kent Beauty’ (Summer), Nepeta (Summer), Sedums or Helianthemum (May-June).