White cedar tips turning brown in part of hedge over the early spring

(Question)

a cedar needles how they look as they start to dieWe live in North York, Toronto area.  After the severe winter of 2015, our cedar hedge looked fine but then in the early spring, about a 6 foot area seemed to be going brown.  The entire hedge gets the same amount of light (hedge goes from North to South and gets light both from east and west) and is in clay soil.  This is the 4th year and they are about 6 feet tall now.  Last year the same thing happened to the same area but the damage was not as extensive.  It seems to be self limiting but I am worried it may not be.  There is a distinct pattern of browning of the tips but not sure it all died off in that manner.  I cannot see anything unusual when I look closely at the tree even with a magnifying glass.  Here is an example of the pattern of tip die off.  The rest of the hedge looks very green and healthy.

This hedge is near a bird feeder and I’m not sure if this is a coincidence or not, but many of the sparrows that land for shelter seem to concentrate in this area in the early spring.  The birds settled there last year too.  Could these be the cause of the browning?

Would you have an idea what this might be as I cannot see anything suspicious?

Should I cut out the brown branches for the health of the tree?  We now have a small hole in our privacy hedge.

(Answer)

First of all, congratulations on having a lovely, healthy hedge of Eastern White Cedar, and having an obviously very appreciative colony of sparrows in your yard!

While the avian population can inflict damage to trees, this is usually limited to physical injury by boring (e.g. Woodpeckers or sap sucking birds).  Furthermore, the resulting holes can also become entry points of pests and disease.  However, sparrows do not seem to pose any risk to trees.

The browning of the tips of your cedar, occuring two years in a row in early Spring and only in one limited area on an otherwise healthy hedge, seems to point to winter injury as the cause.  Cedar leaf scales that are dessicated by winter cold would fade from green to light tan or reddish-brown in the spring – this matches the pattern of browning on your cedar shown in the photo.

Winter injury usually occurs to evergreens that have been exposed to wide temperature fluctuations or strong winds.  Certain locations are especially susceptible, and evergreens planted at these locations would be more vulnerable.  Sites close to surfaces or structures (which reflect heat and magnify the temperature discrepency), spots near exhaust vents or fans, the south and west sides of buildings, and sites that are exposed to prevailing winds could be the cause.
To protect your hedge from winter injury, make sure that the trees are well hydrated by watering deeply until the ground freezes.  You can also provide physical protection in the winter by installing a screen about one foot away from the damaged spot – wooden stakes and burlap can make an ideal windbreak.
Pruning of dead branches can be done at any time of the year, but try to do it before mid-July, so that new growth has time to harden off properly before winter.

 

In the early spring, water these plants well so that they can re-hydrate from any moisture loss over the winter.  At the same time, a top dressing of compost or well rotted manure around the entire hedge planting would be beneficial.