variegated yew tree has dead patches appearing in it. The rest of
the tree seems healthy and there are no obvious insect pests. Can
on yews is usually caused by problems with the root system. Yews
are notoriously susceptible to root damage, which can be caused
by a variety of factors including poor drainage, excessive summer
drought, soil too acid or too alkaline, root injury by insect pests,
too much fertiliser and damage from digging or cultivation. The
dieback symptoms usually start off with an occasional shoot turning
yellow and eventually going brown. If you cut out the dead piece
the tree may look fine for a while, then another shoot may die off
and this sequence of events can go on for years.
Unfortunately, the tree
will probably eventually decline and die. If you can't improve the
soil conditions, you could try spraying it with the fungicide No
Root Rot which may help, but probably only temporarily.
Gardener, Issue 198, 2006, Page 22
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.