How to deal with hol­ly­hock rust

Amateur Gardening - - Your Gardening Week -

HOL­LY­HOCK rust has struck for the sec­ond year run­ning, but I’m hop­ing that this year I’ve caught it early enough to pre­vent it spread­ing to healthy plants and weak­en­ing the af­fected ones to the ex­tent they need to be re­moved and de­stroyed.

This is a fun­gal dis­ease caused by Puc­cinia mal­vacearum and is spread via air­borne spores. The symp­toms are bright or­ange or yel­low spots on the leaf sur­face, lumpy pus­tules un­der the leaves, and spots and pus­tules de­vel­op­ing on the stems. In se­vere cases the leaves shrivel and fall, and the plant loses vigour and be­comes stunted. Con­trol­ling it isn’t easy, but isn’t im­pos­si­ble, ei­ther. Cut off all af­fected leaves and ei­ther burn or bin them. Don’t add them to the com­post heap, and ster­ilise se­ca­teurs af­ter­wards.

Keep plants well wa­tered and avoid dense plant­ing as this will re­strict air­flow. Try not to grow re­lated plants such as lavat­era, hibis­cus and abu­tilon if hol­ly­hocks fea­ture in your gar­den. Dis­pose of af­fected plants and don’t keep the seed from rusted plants for fu­ture use. Check that plants bought in from else­where are free of the prob­lem. In se­vere cases use a fungi­cide such as Bayer Fun­gus Fighter Plus and Scotts Fun­gus Clear Ul­tra.

Re­move and de­stroy hol­ly­hock leaves as soon as they show signs of rust

Fungi­cide can help con­trol the prob­lem

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