She said: “Salvias and roses are a very beneficial planting duo. The sulphur in the salvia’s scent profile means that when they warm up, they release a natural fungicide, which keeps roses super strong and healthy, and mildew and blackspot free.

“Underplanting with salvias is a great organic gardening method, which allows you to forgo pesticides and chemicals.”

It’s best to grow roses in a sunny spot as fungal spores rely on moisture to germinate, meaning shade could speed up the infection, which is “potentially lethal for roses”.

Gardening enthusiast Rebecca Lovatt from the blog My English Country Cottage, also recommended using salvias as a rose black spot deterrent. 

She said: “One of my favourite things about salvias is that they are naturally pest and disease resistant. This means you can even plant them next to roses to help keep black spot at bay.”

Sarah shared the same sentiments on her blog as she said: “One of the things that we’ve experimented with our roses is trying to protect them against blackspot and mildew without using chemicals, and we’ve had huge success with underplanting our roses with salvias.”

She noted that, particularly, the microphylla salvias are the ones to go for. Explaining how salvias deter black spot, she said: “The leaves give off a pungent smell that is slightly sulphurous, and of course sulphur is a fungicide, and my belief is that these salvias have sulphur in their scent profile.

“When they get hot, they warm up and they release that and they just give this whole rose garden sort of puffs of natural, home-grown fungicide, and keep our roses pretty pristine, so I just thoroughly recommend it.”

Sarah pointed out that housekeeping is also “essential” if you find that black spot has already infected your roses. 

If you spot the signs of blackspot, clear away any dead leaves which might work as a natural host for harmful spores.