St. John’s Wort (Hypericum)
Symptom Cause  
Lower foliage looks burned
Dog Urine
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Leaves covered with white powder
Powdery Mildew
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Plants look sickly
Root Knot Nematodes
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Powdery spots on leaf undersides
Rust (on plants)
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Cottony masses or bumps on twigs, leaves yellow, drop; bumps on leaves and stems; sometimes sticky leaves
Scale Insects
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Foliage damaged in winter
Winter Burn
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