Roses are a must for the summer garden. My garden walls, banks and hedges burst into life as they’re carpeted with these magnificent blooms.

But rose blackspot is an unsightly disease that has put many gardeners off growing roses. Many varieties are especially susceptible to it, with their leaves mottled with black spots and sections of stem turning an ugly black. Many years ago I remember my brother proudly showing off his immaculately clean bed of roses, explaining that he had the nearby Ravenscraig steel works to thank for this. Not even blackspot could survive the sulphurous fumes the factory chimneys belched out 24 hours a day.

None of us is cursed by the like of such steel mills any more but we usually haven’t been able to howk out and replace any victims of the disease as rose replant disease could put paid to them.

Replant disease is caused by a soil pathogen which attacks roots and inhibits new roots from growing. Established roses have developed some resistance to the pathogen but replacements can’t. So, unsurprisingly, many gardeners have naturally been reluctant to replace unsightly specimens and have chosen to plant something else instead.

Luckily, help is at hand. One of our most reputable rose growers, David Austin, has decided to ‘retire’ some of its varieties. Paul Constantine, project Director at the firm has noted that ‘due to climate change and evolving diseases’ several varieties, including ‘A Shropshire Lad’, ‘Lady Emma Hamilton’ and ‘Teasing Georgia’, have been discontinued. I have grown ‘Teasing Georgia’ for some years now and have frankly been disappointed by its poor performance.

But you can succeed with new disease-resistant varieties, such ‘Sunny Solution’ or ‘Diamond Dad’ now added to the Peter Beales range. Success with these and many other varieties is highly likely especially if you take a few precautions. Remove the old plant and replace the new soil from another part of the garden. The new hole should be about 60cm2

Add fertiliser such as hoof and horn, mixing in good home compost, if possible. Mix in mycorrhizal fungi, often sold as ‘Rootgrow’ to stimulate root growth.

A better alternative is to dig a hole, again about 60cm square, put a bottomless cardboard box in to it, fill with a mix of fresh soil and home-made compost and plant the new rose in this. The rose should be sufficiently well developed by the time the roots push beyond the box. Disease-resistant varieties increase the odds of success.

Plant of the week

Paeonia ‘Pink Hawaiian Coral’ is a semi-double, early season paeony with coral pink flowers that gradually fade to a more pastel pink. The flowers are held on strong stems that grow to about 90 cm. Hardy and easy to establish a clump will increase over the years to make an impressive display.

Like most peonies, if happy ‘Pink Hawaiian Coral’ will probably outlive you so choose a spot that will please it and you.