Sick Exbury Azalea
Hello. My exbury is next to a fairly new concrete foundation(3 yrs) so may be iron chlrosis but may also be Nitrogen deficiency? Took these pics today so they may only show fall color change but a month ago the leaves were very yellow and many had very thin - 1/8 to 1/16" dark red margins. Have not tested soil. What should I do first? Is it too late this year to add nutrients?