Pacific Northwest Plant Disease Management Handbook

Hypericum (St. Johnswort)-Root Rot

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Latest revision: 
March 2024

Notes Several root rots have been sent in on samples of H. calycinum (creeping St. John's Wort) from the PNW to the OSU Plant Clinic. Pathogens found cause common root rot diseases and include the water loving oomycetes Phytophthora and Pythium as well as Rhizoctonia and Fusarium. Some of these pathogens have been reported in California but none from the PNW.

Pscheidt, J.W., and Ocamb, C.M. (Senior Eds.). 2024 Pacific Northwest Plant Disease Management Handbook.
© Oregon State University.

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  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

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H - Home garden packaging commonly available.     O - Acceptable in organic production.