Blackspot Remedy

Credit: Nigel Cattlin/Holt Studios Photography Library

For a fungicide spray excellent for roses, rhododendrons and other flowering bushes troubled by blackspot, try this recipe:

4 tsp. (20 mL) baking soda
1 tsp. (5 mL) horticultural oil (can be purchased at nurseries or garden centres)
2 Tbsp. (30 mL) 20-20-20
Add this to 3.5 qts. (4 L) water and mix well.

Tap the rose bush so leaves damaged by blackspot fall off, then rake them up and dispose of them. Spray the fungicide mix over the bush once a week to keep it healthy. The baking soda helps prevent mildew, the horticultural oil seals in tiny borers and suffocates them, and the 20-20-20 feeds the plant. An added bonus – the leaves enjoy a healthy shine!