Question
I have a Tibouchina Urvilleana growing in a pot in my yard.  I live in Houston, Zone 9. Every year it starts out well, with big, velvety green leaves.  This year it's blooming more than it ever has.  My problem is that almost all the leaves begin to turn brown and crisp on the ends and edges, and I have no idea why.  Any tips?

Answer
What you describe sounds like drought stress or sunburn.  Try moving the plant to a lower light area if it is in full sun or give it more water.  Do one or the other first and then watch the new grow to see how it performs.  If one does not work then try the other.  You may be able to determine which is the cause with this method.  I hope this helps solve your problem.  Thanks.