www.arborage.com ARBOR AGE WINTER 2015 25
INDUSTRY INSIGHTS
better drainage. Better drainage allows salt to more freely leach
out. A larger rooting volume also brings better drainage and
salt flushing. Also, healthy soil leads to healthy plants that are
better able to withstand salt exposure.
FLUSH THE SOIL
AND/OR THE TREE
Thorough, deep irrigation can
help flush salt out of the soil.
The VCE bulletin recommends
"applying 2 inches of water over
a 2 to 3 hour period, stopping
if runoff occurs. Repeat this
treatment three days later if salt levels are still high." To deal
with salt spray, the bulletin advises to "rinse salt spray off trees
and shrubs after storms and high winds and again in early
spring to remove salt residue from tender buds and leaves."
HOLD THE FERTILIZER, BUT PASS THE MULCH
Since synthetic fertilizers are salt-based, one should use them
judiciously, if at all. Mulching is a good idea, because it helps
the soil to retain moisture, which helps move salt out of the soil.
SOME SURPRISES
"Trees have a great capacity to store chemicals," said Percival.
"Consequently, trees may store salt over a number of years
until eventually a threshold is reached, after which the tree
quickly spirals into a salt
toxicity decline."
Also, a little salt is good!
Percival said that spraying
trees with a weak salt solution
(1-3 grams in a liter of water)
actually toughens them up.
"We call it pre-conditioning,"
he said. "Several nurseries now
pre-condition their nursery-grown trees (which previously
have in essence been 'pampered' throughout their growing
lives) before planting into an urban landscape where salinity
represents a major issue killing hundreds of thousands of
trees annually." Transplant losses tend to be far lower in
pre-conditioned trees.
Michelle Sutton (michellejudysutton.com) is a horticulturist,
writer, and editor.
"
Rinse salt spray off trees and shrubs
after storms and high winds and again
in early spring to remove salt residue
from tender buds and leaves.
"
