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| Apple tree planted in rock mulch |
A. Because the entire tree died from top to bottom we can be relatively certain the problem was at the very bottom of the tree, in the trunk or the roots. The most common reasons are watering too much or too little, planting the tree too deeply, and leaving mulch piled around the trunk when it is young.
First, manually run the irrigation cycle and make sure that water is getting to the tree. If that cycle is operating normally and other plants on that cycle seem to be doing fine then we can probably eliminate watering. But you must check this first since this is the easiest one to eliminate.
Next, let’s eliminate planting too deeply and problems with the rock mulch. Get something to kneel on and pull the rock mulch away from the trunk. With your fingernail or a penknife cut into the part of the trunk, just barely beneath outer bark, that was covered with mulch. Make the same cut into the trunk just above the bark or make one long cut to include both.
The color of the trunk just under the bark should be identical in color in both spots; white not brown. If the color just under the bark that was covered with mulch is brown, then the tree died from collar rot due to the mulch in contact with a young trunk. Never put mulch, whether it is wood or rock, directly against the trunk for the first four growing seasons. Keep its six inches away from the trunk until it is older.
Lastly with the mulch pulled away from the trunk and still on your knees, dig the soil away from the trunk until you find the first roots. These first roots should be no deeper than about ½ inch below the soil. If roots coming from the trunk are deeper than this and soil has been placed around the trunk and the part of the trunk covered by the soil was brown, then it died of collar rot because it was planted too deeply, a common mistake.
Always plant all trees and shrubs with no more than ½ inch of soil covering the roots and make sure the tree is staked the first growing season.
Thank you for this very helpful response. I did exactly as you said and it seems to be collar rot because the (rock) mulch was planted right up to the trunk and when I checked the bark was not only brown but dried out. I’ve moved back the mulch on all of my other trees. Thank you again.
Is free wood-mulch still available at the Master Gardener's Orchard? Thank you…
Yes, come and get it any Tuesday or Saturday morning. Thanks to First Choice Tree Service for their supply of green waste from local trees instead of taking it to the landfill. It is free if you load it yourself. If we load it with a tractor we are asking for a small donation for maintenance and fuel.
Sounds good! Do I feed young fruit trees extra nitrogen when mulching with wood chips? Thanks again…
I really don't add any extra nitrogen with the wood mulch. I know it says to do that in the "textbooks" but I just have not found it necessary but I do put the fertilizer in one location, near the water source, and water it in. I do not spread it under the canopy of the tree where it is diluted. The other thing you might try are the fertilizer stakes. I like them and have used them at the orchard in the past. For homeowners they are less messy than opening a bag and having the possibility of spilling everywhere or getting wet. Just make sure you use enough of them per tree and keep all fertilizers a good distance from the trunk or you can damage the tree.