The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
- When purchasing Heuchera plants inspect the foliage closely, and reject any plants showing symptoms of rust infection
- Consider quarantining bought-in plants, if in leaf, for three to four weeks, particularly if you have unaffected Heuchera plants in your garden. Keep the new plants well away from the others, and inspect them every week for symptoms
- Remove the old, senescing leaves from plants in autumn to help to prevent the fungus from overwintering
- Avoiding growing heucheras in areas with poor air circulation, as high humidity and leaf wetness are favourable for infection
- If the plants are to be watered, do so in the morning so that the leaf surfaces dry out rapidly
- Remove and dispose of any affected foliage – do not compost it
The fungicides tebuconazole (Provanto Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Provanto Fungus Fighter Plus, Toprose Fungus Control & Protect), and triticonazole (Fungus Clear Ultra) are approved for the control of rust diseases on ornamental plants.
The following products contain a combination of both insecticide and fungicide, enabling the control of both insect pests and disease: myclobutanil containing cypermethrin (Resolva Rose 3 in 1, Rose Shield Bug & Fungus Killer, Roseclear Ultra Gun 2, Rosegarde) and triticonazole containing acetamiprid (Roseclear Ultra, Roseclear Ultra Gun).When a proprietary product contains an insecticide as well as a fungicide it would be preferable to use an alternative product if pests are not a problem on the plants treated.
Inclusion of a product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.
Fungicides for gardeners (Adobe Acrobat pdf document outlining fungicides available to gardeners)
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: storing and disposing safely