In grafting pecan trees, we take a piece of one-year-old wood collected from a mature pecan tree and place it on a seedling rootstock tree. If the scion was collected from a vigorous and healthy tree, that small piece of twig will be programed to produce both catkins and pistillate flowers.
The photo at right is a Kanza graft I made this spring. Hanging down over the plastic bag, that I use to wrap the graft union, are catkins produced by the scion. At the very top of the scion's new shoot growth is a cluster of female flowers.
Whenever I see pistillate flowers forming on a new graft I usually pinch them off immediately. At this point in the tree's life, I want to encourage maximum vegetative growth. Female flower production on a new graft only serves to slow shoot growth.