At the end of the summer, many plants begin to put more energy into tip growth and take it away from the lower leaves. They yellow and drop off. Just pick them off and only watch the last two inches of the branch tips. If they are green and growing, all is fine. Eventually, the yellowing will increase as the evening become cool and shorter. The plant is preparing to overwinter its natural drought period, so too many leaves require too much water, so the plant keeps the tip ones last but tosses out the lower ones. Even though you are watering, the age old program in the plants says drought coming, prepare to survive. It will toss all the leaves finally and shut down. Even in moist tropical areas you still see the confused plant go into a dormant phase although it is much shorter. Bill

Hello tdogdad. Glad I've read your remarks they are very informative.I have had a similar experience with the older rooted cuttings and was getting concerned.I have been removing the yellowing leaves and the tips look O.K. so reading your comments makes sense.It seems that since the heatwave here in the U.K. it feels like autumn is coming early with cool winds and rain.Thanks again for sharing your knowledge.
Hazel.