A Driving Instructor's Blog

Silver Birch - summer 2017My article about early leaf drop in Silver Birch trees is very popular – but it has really peaked this year (2018).

My own trees started going yellow this time around in mid-June. After a lot of research, I concluded that it was due to heat stress as a result of the prolonged warm weather and low rainfall we have experienced. I know that some places have had torrential downpours, but it isn’t enough. The temperature has remained pretty much in double digits the whole time, and has been in the mid-20s and low-30s most days for almost two solid months, and with no end in sight.

I commenced deep watering right after I found it as a remedy in June, and it has worked like magic. Right now, I simply set the sprinkler going for about an hour in each of three separate locations, and I do this each night (next year, I’m going to install deep-watering spikes to help the water get deeper into the soil). I have also found a way of watering and fertilizing at the same time.

When trees are stressed as a result of high humidity and low rainfall, they can’t get enough water and begin to shut down just as they do in the Autumn. It doesn’t kill them unless it happens year after a year, but obviously you can take steps to deal with it once you notice it.

My Silver Birch in 2017One thing I have noticed with the benefit of hindsight is that the foliage on virtually every Silver Birch I have seen this year is thinner than in previous years (that’s also true for a lot of other trees I’ve seen). The leaves are actually smaller. The reason I say “hindsight” is that about a month into deep-watering and my tree has put out some significant new growth and the leaves on that new growth are much larger, and just like the photo I took last year.

Note that we have no hosepipe ban, and I wouldn’t be doing this if we did.

Once I commenced the watering, the yellowed leaves all fell over the next week or so, but no more were produced. Right now, not a single leaf has fallen in the last month at least and the whole tree is green with the aforementioned new growth. It is also producing fat catkins.

Will a Birch recover from drought?

It depends on whether the drought killed it or not. A reader wrote to me last year, mentioning that his tree had lost its leaves, and I advised that the only thing he could do right then was to feed and water – and hope for the best. He wrote to me recently to tell me the tree had started to rock in the wind, and that a tree surgeon had subsequently declared it dead, and had had to remove it. Apparently, the roots were rotten.

There’s no way of knowing if it was just the drought that did the damage. The tree may have been weakened by not feeding and watering over previous years, and the drought was just the final nail in the coffin. But last year’s drought certainly caused problems.

By now – early April 2019 – Birches are showing profuse growth of leaves and catkins (mine is). If yours is still completely bare then it doesn’t look good. Last year’s drought did a lot of damage, and since not many people do the feeding ritual that I have covered in the main leaf drop article, trees may already have been struggling.

That said, mine has certainly recovered from last year’s drought, although I did catch on very early and stopped it becoming a major issue.

All I can say is: water (if it’s not raining much) and feed.

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