Real World Gardener Controlling Black Spot on Roses in Plant Doctor

October 9th, 2015

REAL WORLD GARDENER Wed. 5pm 2RRR 88.5fm Sydney, streaming live at  and Across Australia on the Community Radio Network.
Real World Gardener is funded by the Community Broadcasting Foundation (CBF).

The complete CRN edition of RWG is available on , just click on 2RRR to find this week’s edition



We love our roses don’t we?

What’s not to like? 
Just inhale the perfume, and feast your eyes on the shape and form of the flower and the whole gorgeousness of a bunch of roses.

On the other hand, there’s the thorns on most, the pruning and the dreaded diseases that they get if they’re not in the right environment.

So what can we do about the most common problem on roses?


Talking with eco Organic Garden General Manager, Steve Falcioni





Black spots have a soft edge and initially they're just black about the size of a pea.

As the fungus progresses the leaf yellows and then drops off.


symptoms show up 3 to 10 days later of mild temperatures of around 24 degrees Centigrade and high humidity.

Usually black spot starts on the lower leaves and works its way up,

Sometimes it can defoliate the whole bush.

Even though you've sprayed your roses in winter to control fungal problems, fungal spores blow in on the wind from somewhere else.

Some of the cultural controls they you need to do before spraying are:-make sure your rose has 6 hours of direct sunlight and logs of good air movement.

Winter pruning should have opened up the bush as a way of reducing the humidity issue.

Also rose are heavy feeders so make sure your roses are well fed.

I hope this peaks your interest in getting out there and spraying those roses with whatever method of control you choose.
Starting early is a good way to get a jump on those fungal diseases before the weather warms up and the humidity increases.

Organic sprays include whole cream milk, but is only effective if sprayed on sunny days.

Bi-carb soda and horticultural oil.


Potassium bicarbonate sold as eco Carb fro,

Potassium bicarbonate changes the osmotic pressure on the leaf causing any fungal spores to burst.

While you’re out there, why not pick some roses for inside the house.
If you have any questions about your rose bushes or have some information you’d like to share, why not email or write in to 2RRR P.O. Box 644 Gladesville NSW 1675.

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