It could be several reasons.  Is it possible you could attach at picture?  Thanks, A

Here r several pictures. 

Well, it looks like something is keeping the normal load of nitrogen from the plant taking what it needs to keep your plant healthily. It could be because the pH is way off. What is the black charcoal looking stuff near your plant? If it is charcoal and ash that would not be good. Get your soil pH tested if possible. In the mean time, feed your plant with a foliar fertilizer like Miricle Grow but dilute the solution by half. Spray this solution on the leaves every two weeks until we know what is or if something is going on with the soil. Also, check for any pest on the plant by tapping the stems of the plant onto a white bond paper. If there are any insects that drop onto the page, use see through tape to capture the insects. Take a picture and send them to me. Talk to you soon. A Let me know if you have been adding wood ash to your soil and the pH results. A