Panicle Hydrangea Yellow Leaves

(Question)

I got this hydrangea last year, and I planted in a pot outdoor. It was blooming well last year, and the leaf growth has been pretty good this year. However, the leaves were gradually turning yellow since it started to grow its flower balls. All of the leaves are affected by this, and majority of the leaves are now gone. The falling leaves are not completely yellow. The flower balls have also stopped growing.

I fed the plant with 20-20-20 fertilizers early spring. And my watering schedule has been pretty consistent with what I have been doing.

What could have gone wrong? And is there any remedy to improve the problem? Thanks!

(Answer)

It is unfortunate to have a plant that gave so much pleasure last year take a turn this year.

Brown, tan, yellowish or black spots on hydrangea leaves may be anthracnose. You can also identify it by cankers that form on stems and branches. Anthracnose can be fatal to hydrangeas, so prune out dead or diseased plant parts and destroy them.

The Plant Addicts nursery in Nebraska suggests on their web site the following three reasons for yellowing leaves in hydrangea:

  • The plant has become too dry
  • The plant has been kept too wet
  • The plant has received too much fertilizer.

Click here to access their information on how to identify these issues and how to correct them.

If any of the leaves also appear to be chlorotic, pale green, this means that the plant is not able to absorb iron and other trace minerals from the soil.  Often high pH (i.e. basic soil) prevents these nutrients from being absorbed by the plant.  You may consider amending  your soil.  To accomplish this, add a layer of really good triple mix.  Two or three inches of organic matter including clumpy aged manure, might help strengthen the immune system of your hydrangeas, change the environment for the bugs, and help prevent reoccurrence of pest problems. No need to dig it in.   Another idea  is to remove some  older plants to allow more air circulation as well as allowing the  uptake of  more available nutrients per plant.

Below is a link to an article which lists common hydrangea problems.

https://www.hgtv.com/outdoors/flowers-and-plants/trees-and-shrubs/a-hydrangea-problems-primer

Good luck with your hydrangea.

June 26, 2024