Q What are the symptoms of heuchera rust?
A Look for small brown spots, sunken depressions or raised bumps on the upper leaf surface of heucheras and raised, orange-brown spore producing pustules underneath the leaves. (Sometimes, pustules may also be seen on upper leaf surfaces, too.) Younger leaves often become distorted, while older foliage tends to shrivel up and turn brown. Older spots may fall out, giving a ‘shot-hole’ appearance to leaves. Affected plants also lose their natural vigour.
Caption: Heuchera rust pustules on the lower leaf surfaces
Q How do I control heuchera rust?
A When buying new plants, check the leaves carefully and avoid any showing symptoms. Remove and dispose of affected leaves on existing plants promptly – don’t compost them. Water early in the day, so that leaf surfaces dry out quickly; constant leaf wetness favours the disease. Clean up border plants in autumn to reduce overwintering infections, which can spread to new spring foliage.
Caption: Sunken depressions on the upper leaf surfaces of heuchera
Q When did heuchera rust arrive in the UK?
A It was first recorded in the UK in 2004. It's common in the US and well-known here commercially, following a surge in nursery production, although generally it’s been less prevalent so far this year. In the UK, only heuchera has been affected so far, although in the US, other members of the Saxifragaceae family have been attacked, including saxifraga, tellima and tiarella.