Hi, I have an AP-Burgundy Lace probably over 6yrs old, the main trunk is about 1.5inches and the scion is now 1.0". But at the graft union there is a noticeable bump (photos) on one side of the graft. Can anyone share how we can get rid or reduce the bump scar?. Thanks.
You can give it time and as the tree ages and thickens it will become less noticable. Taking action would involve investing in a quality knob cutter sold for bonsai. Or a concave cutter is a more modern version that is less aggressive. You would use a high quality fine tooth bonsai saw to saw the bump leaving about 1/4" proud. Then with the concave cutter flush against the trunk, you will remove the remaining, causing a slight shallow concave bowl in the trunk. The wound wood will form and fill the shallow bowl closing the wound flush with the trunk. Given that this is a critical zone of the tree where extreme moisture loss and tissue dieback could be catastrophic for the tree, I would recommend sealing the cut with waterproof outdoor glue like Titebond 3. The least invasive would be to use PHC Roots Healthy Start fertilizer with rhizobacteria which improves the trees health by: improving root growth up to 70%, fungal and bacterial resistance, improves drought and cold resistance, improves the trees ability to take up nutrients, thickens trunk and improves wound healing time, improves spring and fall colors while lengthening the show of color by over 50%. I buy mine from Great Garden Supply PHC Healthy Start (3-4-3) 25lb. My product recommendation comes from experience over several seasons and seeing the results and the drastic difference the product makes in my collection. Use it on all your maples in ground or potted and you will be recommending it too. I do not benefit in any way by my recommendation as I have no affiliation with the product or retailers who sell it.