It’s at this time of year when the nation’s favourite plant – the rose – gets attacked by the dreaded blackspot.
The disease thrives in warm moist conditions, and most early attacks come from those spores that have spent the winter in uncleared plant debris or in dormant buds.
You’ll know if your plant has it if its leaves look anything like that in the photograph (right).
Good garden hygiene plays a large part in keeping blackspot under control.
You’ll go a long way in breaking the life cycle of this disease if you gather up the fallen leaves around the base of the plant. During the season, it’s important to pick off the worst affected leaves and dispose of them very carefully. Place them in a plastic bag and tie the top tightly.
Leave the bag in the hot sun for a few days, and then put them into the dustbin or burn them. This should kill off the active organisms to prevent further infection. Under no circumstances put leaves affected by blackspot into your compost heap.
Spray the plant with a fungicide of your choice – mine is Rose Clear Ultra
Growing garlic or onions with roses is said to help deter black spot, though there’s no scientific evidence that it actually works!
I have a recipe for a garlic wash, which you are welcome to try – just email me. But there is also no doubt that a plant that is well fed and watered is able to better withstand the onslaught of any fungal attack