is wrong with my well established rose bushes - and is there a cure?
A couple of my roses went like this last season. I thought it might
be weed spray but none has been anywhere near them. My roses are
regularly sprayed with two different rose sprays, alternately.
photo had me puzzled too, as it does look like herbicide damage.
However, I sought advice from rose expert Doug Bone who reports
he has seen symptoms like this before. In all cases, the affected
roses eventually produced healthy growth as spring progressed.
Experts he's consulted
consider the problem to be a nutrient deficiency, not caused by
lack of fertiliser in the soil but by leaf growth in early spring
occurring faster than root growth, so there's a temporary lack of
nutrients in the plant tissues. I think it's likely certain weather
conditions could increase the problem, such as a warm spell encouraging
bud growth, followed by a cold snap.
Other factors probably
play a part too, such as soil type and drainage, and some rose varieties
are probably more susceptible to the problem than others. So the
general consensus is that your plants should improve as the soil
warms up. If not, don't hesitate to let us know.
Gardener, Issue 133, 2003, Page 28
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.