Reply
Super Contributor
Posts: 264
Registered: ‎03-09-2010

I have lots of Azaleas in my yard and see  the leaves are looking yellow on quite a few. They are not dry, lots of rain this year. I'm sure the soil needs to be acidified but I can't find anything on WHEN. They look bad, hate to wait till spring. Would something like Hollytone be ok for winter application?

Super Contributor
Posts: 285
Registered: ‎08-03-2019

Not sure what is going on. Could be they need a lirrle Miracle-Gro or something like that. I had Azeleas back north that I took inside winter. 

Honored Contributor
Posts: 56,624
Registered: ‎03-10-2010

@Summer Shine.  Talk to @Justjazzmom our resident Master Gardner.  

 

@Justjazzmom 

 

New Mexico☀️Land Of Enchantment
Honored Contributor
Posts: 12,507
Registered: ‎03-15-2014

Do you have an evergreen azalea - usually found in warmer climes - or deciduous?  Leaves on deciduous types - found in colder areas - would be turning yellow and dropping about now.  At least, mine are.  

Honored Contributor
Posts: 20,341
Registered: ‎03-09-2010

As to when to acidify the soil, you can do that at any time. If you think your plant is in serious stress, you'll want to use a faster acting soil acidifier. Some materials act quickly while others slowly alter the soil. Vinegar acts very quickly. Some other methods take a long time.

 

A soil test first might be wise as there are other things that could be causing the issue. I doubt that it's a sudden drop in soil ph unless you live in an area with alkaline soil and/or have added materials to lower the ph that could have been washed away by the rain. Rain water these days is typically acidic (acid rain) and that alone can often act to acidify your soil. 

 

Checking the underside of yellowing leaves for any insects would be wise also. You could have a spider mite infestation. There's also a stunt nematode that eats the feeder roots of azaleas. Too little iron in the soil could be the cause. Poor draining soil could drown the roots. (You did say there had been a lot of rain.) There are lots of options that could be causing your issue besides the soil ph, so a soil test would let you know for sure if it was ph related.

Fly!!! Eagles!!! Fly!!!
Super Contributor
Posts: 264
Registered: ‎03-09-2010

Thanks for the all the replies. I have the evergreen type shrubs. I will test the soil, have to pick up a ph kit. I don't see any evidence of pest problems. I appreciate all the advise.

Honored Contributor
Posts: 17,146
Registered: ‎03-09-2010

Uniformly yellow leaves on an azalea with a dark green center vein on the leaves indicates chlorosis which is an iron deficiency. This happens when the acid loving roots come near or in contact with brick or cement foundations or hardscape. The lime that leeches into the soil is absorbed by the plant and it shows up as an iron deficiency. Here is a photo to show an example.To correct this, you would have to buy Ironite and follow label directions. It adds iron back into the soil and helps the acid loving plant by decreasing the pH of the soil.  This is a temporary fix. You would have to add more acidic things into the soil like peat moss or compost to lower the pH for the azalea which is generally around 5.5 pH.. You can use Holly Tone fertilizer for acid loving plants too.

 

Iron Chlorosis

 

 

https://www.purdue.edu/hla/sites/yardandgarden/interveinal-chlorosis-on-azaleas-and-rhododendron/

 

 

 

☼The best place to seek God is in a garden. You can dig for him there. GBShaw☼