Salt-tolerant plants for sodium-laced soil

Gardening by the seashore
Unlike gardeners who battle road salt for only a few months of the year, coastal gardeners have the year-round challenge of battling windblown salt spray and gardening on excessively fast-draining sand dunes or impermeable rocks. Even foggy weather can carry salt-laden moisture onto plants. In extreme cases, plants are subjected to salt-contaminated groundwater, too.

After a major storm, seaside gardeners should immediately start irrigating their soil and plants for a few minutes to flush away salt. If salt water has flooded the area, deeper leaching is needed; depending on the extent of flooding and the amount of sand present, irrigation may be required for several hours. The sooner sodium is diluted in the groundwater around plants, the better their chances of survival. Watch for signs of distress—wilting or browning leaf edges, which can occur within a few days or weeks.

Building a windbreak or choosing tough, halophytic plants (those adapted to saline conditions) is a good strategy for seaside gardeners. Plant a dense, multi-layered, evergreen and deciduous windbreak (such as blue spruce or Austrian pine) as the first line of defence from the elements. This permeable barrier (often sturdier and longer-lasting than a fence) will slow the wind and trap salt spray before it reaches tender plants farther inland.

Pro tips: Repelling road salt

• Use mulch as a protective barrier to trap salt. Put down layers of mulch before winter and dispose of it come spring.
• Add lots of organic matter to the soil to help drainage—especially important in heavy clay soils.
• Condition soil with gypsum (available at garden centres). Add in late fall, which will help leach the salt from the soil. 
• Edge the garden for drainage by creating a 15-centimetre-deep trench for the winter. If the garden borders a road, sidewalk or driveway, put the trench between the concrete and the garden. Another strategy is to build up the bed 30 centimetres so salt drains off.
• Don’t stockpile salty snow on flowerbeds.
• Water lawn thoroughly in spring to help flush away road salt.
• If you’re unsure about salt levels, get your soil tested.
• Ideally, keep plants at least four metres back from the main roadside.
• Spray plants with an anti-desiccant, such as Wilt-Pruf or Cloud Cover, in the fall.
• Erect a barrier—such as a hedge—to protect plants.

Read more in Plants and Perennials