Tristan wrote:

We have a North/South aligned path running from our front door along the
side of the house to the garage, it is shaded on both sides and the
Northern
end so it gets very little sunlight. The Orange Jessamines are doing
fantastically but everything else seems to be covered in a white fluffy
fungus. The roses are especially affected, I know its too dark for them
really but we would like them to stay. The Gardenias are also affected,
however the very sick gardenias are the ones closest to a rendered brick
wall, which actually acts as a retaining wall for about 40 cm of next
doors
land. I was wondering perhaps if excessive lime was leaching out of
the wall
and into the soil. The Gardenias also have a brown sooty coating, plus
what
I think is scale, and occasionally those little marshmallow white things.
Can any one help? We are in Perth.


Tristan

Get a pH test kit from a garden centre to test the soil. Add sulphur if
it is too limey.

Is the fungus like a powdery layer on the leaves, or like bits of fluff
stuck to stems and under leaves? If it's the latter, it's from the
mealybug. If white oil doesn't work, try methylated spirits. If there is
lots of fluff around be prepared to do followup sprays regularly, or
drench the soil with malathion, as they lay eggs underground.

If it's powdery mildew, then you could spray with wettable sulphur. This
is a good time of year for that. Follow the instructions as you can burn
the plants. Someone suggested Bordeaux mixture a while back, and someone
else suggested milk, so you could try them.

White oil will also treat scale and sooty mould. Check for ants, too.


Jane