Flower bud glaucescence 

Glaucous (white with wax): the buds are prominently covered with a surface white wax (e.g. E. caesia). This condition must be assessed with care. Because the wax is superficial, it may rub off easily. On some parts of the tree the buds may be green, on others they may be waxy. Obviously, if most buds show the wax, the plant is considered to have glaucous buds.  
Not glaucous (wax absent): buds are usually green or yellow to cream or tinged with red or brown.