How Can I Stop Physiological Leaf Blight of Phlox?
By: Jessie Keith
“I have phlox growing in a big container. The bottom leaves are looking mottled/veiny. I have fed them and also added iron, but it doesn’t seem to be improving. Is there something else it needs?” Shawn from Kenosha, Wisconsin
Answer: Tall phlox (Phlox paniculata) varieties are prone to a series of diseases and foliage disorders, but yours sounds like it is physiological leaf blight of Phlox. It is a physical disorder caused by a water imbalance in the plant that can occur in some tall phlox varieties. Water circulation goes haywire–causing water to bypass the older leaves and only supply water to the new shoots. Here are the symptoms and solutions for this disorder:
Physiological Leaf Blight of Phlox Symptoms
- Mature clumps are most often affected.
- Lower leaves become mottled with prominent green veins before they eventually shrivel and die.
- New growth is not impacted.
Physiological Leaf Blight of Phlox Solutions
- Cut plants back at the end of the growing season, yearly.
- Mulch plants to conserve water.
- Water a little bit extra–though this only works in mild cases. Sometimes the circulatory disorder simply disables older leaves from accessing water.
- Choose a resistant variety, such as the white Phlox ‘Minnie Pearl’ or the shorter “tall” phlox varieties like Phlox paniculata FLAME™ Coral or Phlox paniculata ‘Pixie Twinkle’.
I hope that these tips help!
Black Gold Horticulturist
This site may contain content (including images and articles) as well as advice, opinions and statements presented by third parties. Sun Gro does not review these materials for accuracy or reliability and does not endorse the advice, opinions, or statements that may be contained in them. Sun Gro also does not review the materials to determine if they infringe the copyright or other rights of others. These materials are available only for informational purposes and are presented “as is” without warranty of any kind, express or implied, including without limitation warranties of merchantability, fitness for a particular purpose, and non-infringement. Reliance upon any such opinion, advice, statement or other information is at your own risk. In no event shall Sun Gro Horticulture Distribution, Inc. or any of its affiliates be liable to you for any inaccuracy, error, omission, fact, infringement and the like, resulting from your use of these materials, regardless of cause, or for any damages resulting there from.