On May 25th 2007 I purchased a 6ft valencia orange tree in a 17" black plastic pot at Humber Nurseries in Toronto. This orange tree was stored in their tropicals greenhouse. The tree already bloomed and oranges were forming 2 oranges the size of a little bigger then a golf ball and a whole bunch of small ones (total orange apprx 18). It looked like the were a lot more that the buds fell off, I know they can be sensitive. I took the orange tree home and placed it in my backyard on top of my patio stones, my backyard faces southeast sun all day. I gave it a good watering. The last 3-4 days I must of lost about 3 dozen leaves off the tree. The leaves were smooth pale greenish yellow colour. What could be the problem? The fruit on the tree is OK and growing.