Ask EcoBeneficial!

I have a row of White Pines planted by the road in my front yard. This spring they look terrible.  Is there anything I can do?

Answer:

Roadside plantings can be difficult for many reasons. Some of the biggest challenges include the impact of road salts in winter, pollutants from the roadway, infertile soil, and erosion from stormwater runoff.

The past winter was a doozy in much of the country – lots of cold weather, vast amounts of snow, but even worse for plants, seemingly endless applications of road salt and de-icers.

“Planting the right plant in the right place” may be the most important credo in landscaping and gardening. When the wrong plants are planted, they suffer the consequences of our poor plant selection. Salt-intolerant plants should never be planted roadside, but unfortunately, they often are.

A classic example of a salt-sensitive plant is the White Pine (Pinus strobus) – often planted along highways and parkways in the Northeast. This native tree is extremely intolerant of road salt and frequently suffers major dieback after a rough winter, which becomes particularly evident in the spring and is different than the tree’s normal needle-drop of aging needles.

White Pine is impacted by the residual salt in the soil as well as the salt spray which lands on its needles. According to Laura Deeter, Professor of Landscape Horticulture and Horticultural Science at Ohio State University, White Pines can be affected by salt spray as far as 1,400 feet from the road!

It pays to select native woodies that are gritty and can handle the tough conditions that roadside planting brings. A good native plant choice for a roadside planting is Eastern Redcedar (Juniperus virginiana). It is a small to medium sized evergreen tree that can take road salt with a good tolerance for both soil-borne salt and salt spray.

The evergreen needles of Eastern Redcedar provide cover to overwintering birds and small mammals and its drupes feed over 40 species of birds. It’s a dioecious plant (separate male and female plants), so plant both for fruit production, unless you have many nearby.

I do not recommend removing mature native trees – if they are healthy. It would take a young replacement tree many years to provide the same wildlife habitat and other ecosystem services as a mature tree. But, if your White Pines are on their last legs and likely to get pounded by road salt year after year, think about some native salt tolerant replacements, including Eastern Redcedar. I would stagger the timing of the replacements for the reasons mentioned.

Best of luck!
Kim Eierman at EcoBeneficial!

Photo: Salt Damage to White Pine
Photo credit: University of Minnesota Extension