Salt in the Earth
Partial shade
Average to dry soil
If you live along a coastline, you probably aren’t surprised to find out that you need to consider salt tolerance when you choose perennials for your garden. But even gardens far inland can have a problem with salty soil: specifically, plantings sited along streets, sidewalks, and other surfaces where deicing salts are used in winter. You can still have a pretty garden in these tough spots, though, if you choose perennials that can tolerate some salt.
The Garden Plan
Shopping List
1 Wild columbine
Aquilegia canadensis
3 plants
Zones 3–9
Alternates: Another 1- to 3-foot-tall perennial that can tolerate shade and salt, such as ‘Brunette’ bugbane (Cimicifuga) [1 plant] or a tall astilbe (Astilbe) [3 plants]
Wild columbine (Aquilegia canadensis)
2 Lady’s mantle
Alchemilla mollis
4 plants
Zones 3–9
Alternates: Another 8- to 30-inch-tall perennial that can tolerate shade and moist soil, such as ‘Citronelle’ or ‘Obsidian’ heuchera (Heuchera) [4 plants] or yellow foxglove (Digitalis grandiflora) [4 plants]
Lady’s mantle (Alchemilla mollis)
3 Japanese painted fern
Athyrium niponicum var. pictum
5 plants
Zones 4–9
Alternates: Another 8- to 18-inch-tall perennial that can tolerate shade and salt, such as ‘Hermann’s Pride’ yellow archangel (Lamiastrum galeobdolon) [5 plants] or Lenten rose (Helleborus × hybridus) [5 plants]
Japanese painted fern (Athyrium niponicum var. pictum)
4 Blue lilyturf
Liriope muscari
3 plants
Zones 5–9
Alternates: Another 6- to 12-inch-tall perennial that can tolerate shade and salt, such as lamb’s ears (Stachys byzantina) [3 plants] or dwarf Chinese astilbe (Astilbe chinensis var. pumila) [3 plants]
Blue lilyturf (Liriope muscari)
5 ‘Angelina’ sedum
Sedum rupestre
6 plants
Zones 3–8
Alternates: Another 4- to 8-inch-tall perennial that can tolerate shade and salt, such as barren strawberry (Waldsteinia ternata) [6 plants] or ‘Illumination’ periwinkle (Vinca minor) [6 plants]
‘Angelina’ sedum (Sedum rupestre)
Planting Plan
Season by Season
Spring: The growing season kicks off early with a flush of fresh new leaves on most of the perennials — the bright yellow foliage of ‘Angelina’ sedum is especially showy — with the purplish fronds of Japanese fern coming up a few weeks later. It doesn’t take long for flowers to join in: first the nodding, red-and-yellow blossoms of wild columbine, usually starting in mid spring, and soon followed by the frothy greenish yellow clouds of lady’s mantle.
Spring cleanup is minimal: simply snip off any remaining leaves on the blue lilyturf, rake out any debris, and add a fresh layer of organic mulch.
Summer: Wild columbine finishes flowering in early summer, if it hasn’t already, and so does the lady’s mantle — just about the time that ‘Angelina’ sedum sends up its clustered yellow blooms. (You may not notice the sedum flowers, though, against the bright yellow foliage.) The gray fronds of Japanese painted fern and rich green lilyturf leaves look good all through the summer. Blue lilyturf is also accented with spikes of small purple-blue blooms in late summer.
Trimming off the columbine and lady’s mantle flower stalks when the blooms are done will make the plants look tidier for the summer and may even promote some late summer rebloom on the lady’s mantle. Or, leave them in place until they turn completely brown, if you’d like to give them a chance to drop their seeds and produce seedlings. Most of these perennials can tolerate dryish soil, but it’s a good idea to water this garden during extended dry spells, especially for the first few years after planting.
Fall and Winter: Fall interest in this salt-tolerant garden mostly comes from the variety of leaf shapes and colors. Freezing weather will nip the wild columbine and Japanese painted fern first, and eventually the lady’s mantle; cut off the dead tops in mid to late fall. ‘Angelina’ sedum and blue lilyturf can remain attractive through the winter months.
Early to mid fall is a fine time to divide any of the perennials that are outgrowing their space. (The sedum, in particular, can spread somewhat quickly once it settles in.)
Digging Deeper
- Use this rectangular planting to fill a corner between your driveway and sidewalk, or as a mini-border in any site where salty soil is a problem. If you need to fill a larger space, or if you want to use this simple plan as the basis for a longer border to edge a driveway or sidewalk, simply repeat it end to end as many times as needed.
- Gardens right next to streets and roadways are subject to salt-laden spray from passing cars, and even salt-tolerant perennials can benefit from extra protection in these tough sites. Try applying a protective mulch, such as cut evergreen branches or straw, to catch some of the salt; remove it at the end of the snow season.
- Wild columbine (Aquilegia canadensis) is less likely than most other columbines to be damaged by leaf miners (tiny pests that chew pale, winding tunnels in the leaves), but if you do notice a lot of leaf damage, it’s fine to cut off all of the top growth in midsummer; new leaves will appear in a few weeks. A similar midsummer shearing also works well on lady’s mantle if the leaves look dull and tattered.