Pecan seedling or grafted tree: How to tell the difference

   Several weeks ago I received and email from a grower that had was having trouble determining if the shoots growing from a newly planted tree were coming from the scion cultivar or from the seedling rootstock. Once you learn what to look for, telling the difference can be easy.
    In the photo at right, the leaf on the left was produced by a trunk sprout originating from below the graft union. The leaf on the right came from the grafted portion of the tree.
    Early in the growing season, juvenile leaves have a reddish appearance compared to the bright green of leaves growing from mature wood (the scion). But by mid summer the color differences are more muted. 
    Look at the color of the rachis of each leaf (the rachis is the stem-like structure to which the leaflets are attached). By mid-summer, the red coloration of the rachis of the juvenile leaf (at left in photo) has faded and is now dull greyish-green. In contrast, the mature (grafted) leaf has a rachis that is bright green in color.

    Taking a closer look at these two leaves reveals stronger differences between juvenile and mature leaves. I flipped the leaves over and took a close-up photo of the rachii of these two leaf types (photo at left). Note that red pigmentation can still be seen on the juvenile leaf, especially at the point where the leaflet attaches to the rachis. The mature leaf has no red coloration.
   Now, look closely at the surface of the juvenile rachis. Note the small hairs that cover the rachis and the petioles of the leaflets. To the touch, these plant parts feel rough especially when compared the the smooth rachis of the mature leave.
     Many pecan growing novices end up caring for a pecan tree for 20 years and never see a pecan crop.  They most likely ended up with a seedling tree because the graft died sometime after planting and then sprouted from the rootstock. To avoid wasting 20 years waiting for a seedling tree to produce, learn to recognize juvenile leaves, then brush up on your grafting skills to topwork any seedlings while they are still small enough to graft.