GLT's Grow: Downy Mildew Hits Impatiens

Jul 7, 2017

Impatiens downy mildew is a growing problem in gardens across America. Defoliation and flower dropping are two signs your plants are infected.

  • Impatiens are an enormously popular bedding plant that love the shade, though there are sun tolerant varieties.
  • What this sweet-looking plant can't stand is too much heat and humidity. That potent combination leaves the plant open to downy mildew.
  • When the mildew first strikes, leaves curl under and turn light in color, blossoms drop and a fluffy white growth manifests under the leaves.
  • To reduce humidity, space your plants so that air can circulate between them. Incorporate some sand or pea gravel to enhance drainage in your bed. Cover with mulch, 2 to 3 inches. Plant your impatiens through the mulch.
  • Growing the plant in a pot can help. Use a soil-free potting mix only. That's the key to protecting against mildew. Make sure your pot has drainage holes in the bottom.
  • Rosemary or Neem oil can help you treat plants in the ground that show signs of downy mildew.

WGLT depends on financial support from users to bring you stories and interviews like this one. As someone who values experienced, knowledgeable, and award-winning journalists covering meaningful stories in central Illinois, please consider making a contribution.