Pineapple sage leaves turning yellow
I have three plants, two planted in one location and one in another. The two together are doing great and growing nicely, the other seems to ge growing okay but the underleaves are turning yellow. I don't think this is a case of the older leaves yellowing to allow for new growth as in some plants. My soil is slightly acedic which I know they prefer alkaline so I'm wondering if I should add lime. Funny thing is that everything else I plant besides my salvias like acedic to slightly acedic soil. My pH is 6.6 in most sites so I usually add acedifying materials to my acid loving plants but have not amended for my Sages.
Any other ideas as to why this might be or should I stick with my suspicions?