The main failed graft indicators you'll notice are brown wood, shriveled bark, and dead buds on your scion. While the rootstock keeps growing strong, the grafted piece shows no signs of life. These symptoms tell you the two pieces never formed the bond they needed to share water and nutrients.
I tested dozens of grafts each spring for years and learned to read the signs early. One season I checked a row of apple grafts and found three that looked perfect while two had turned brown. But here's the thing: one of those brown scions came back to life two weeks later. Now I wait a full six weeks before I declare any graft dead for good.
Graft failure signs show up when the cambium layers don't connect the way they should. The cambium is where new growth happens, and both pieces must touch at this thin green layer. If the scion dries out, gets infected, or moves around before it heals, the cambium dies. Once that happens, no water can flow from root to scion.
How to tell if graft failed comes down to a simple scratch test. Use your thumbnail to scrape a tiny bit of bark off the scion near the graft union. Live wood shows bright green tissue under the surface. Dead wood looks brown or tan with no moisture. This quick check gives you a clear answer when you're not sure about a graft's status.
Check for callus tissue at the graft union around four to six weeks after you made the cut. Healthy grafts form white bumpy tissue where the two pieces meet. This callus means new cells are growing and the union is taking hold. No callus after six weeks points to unsuccessful graft symptoms that mean the bond never formed right.
Compare your questionable grafts to ones you know took well. Successful scions swell at the buds and push out new green growth within four to eight weeks. Failed scions stay the same size or shrink a bit as they dry out. The contrast between living and dead grafts becomes clear once you see them side by side.
Watch for mold or fungus growing at the graft union as another failed graft indicator. Gray or white fuzzy growth means infection has set in, which kills the scion fast. Black spots on the wood signal disease that spread before the graft could heal. These problems often start when you skip tool cleaning between cuts.
A scion that leafs out and then wilts down shows delayed failure. The buds had enough stored energy to push growth, but the graft union never formed well enough to supply water. These grafts trick you into thinking they worked before they collapse. Check for firm callus tissue around the union to avoid this surprise.
Don't give up too fast on grafts that look rough in their first month. In my experience some take longer to wake up than others based on the variety and weather. Mark your calendar for a six week check date and do the scratch test then. If the scion shows brown wood with no callus forming, cut your losses and try again next spring.
Read the full article: Mastering Grafting Fruit Trees: A Complete Guide
