Hi, I'm wondering if anyone can help with my gardenias. They have what looks
like a black mould or soot all over the leaves. Am I correct in assuming it
is scale or is it a fungus. We have had very hot summers and the plants
probably haven't had enough water and fertilisation. I have recently learnt
that they do need a bit of feeding.
Gardenias require acidic, fast-draining soil that is always moist
but never really wet. When I planted my gardenia, I mixed a
generous amount of peat moss into the soil. Once a year, I
sprinkle some soil sulfur around it. About twice a year, I add
enough gypsum to hide the soil, which is heavy adobe clay. The
gypsum keeps the clay porous and improves drainage.
They are heavy feeders. I feed my gardenia whenever I feed my
dwarf citrus, lightly twice a month from early April through mid
October. I alternate, using citrus food (yes on the gardenia) and
ammonium sulfate. Each time I feed, I also add a large pinch of
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.