My Trachelospermum jasminoides leaves are covered in a thick black sooty layer. This happened last winter and I guess it is because the spot where it is growing doesn’t much much sun in the winter months. Is there any non-chemical spray I can use or should I cut it right back now and then replant it? It has been in preent position for about 4-5 years and is a vigorous plant, so I assume that the black “soot” isn’t going to kill it but it is very unsightly. It does however flower well in the summer on the new growth..
Certified GKH Gardening Expert
This was likely brought about by an insect infestation, at one time. Aphids will cause this, usually.
What you describe for winter conditions will make things worse, for sure, though.
Unfortunately, cutting them back will not solve the issue. Whether you choose organic or synthetic chemicals, chemicals will be needed, however.