Q.Magnolia leaves turning dark red
Hello, we have recently planted a Yellow Lantern magnolia and over the past two weeks the new leaves are turning a dark red colour. We put the ashes of a friend in the hole when we planted it. Would this be the cause of the problem? We have also heard it could be due to magnesium or iron deficiency, or too alkaline soil. Thanks for your help.
Certified GKH Gardening Expert
Unfortunately, this is the cause. You can't use un-composted ashes, no matter what the source. From this point, I would add something such as iron sulfate, or wettable sulfur to bring the pH of your soil back down... I would imagine that it is well up into the 8 point range.
Ashes, when added to compost as it is composting, will help add trace minerals and some macro nutrients.
Here is a composting guide to help you get started: https://www.gardeningknowhow.com/composting/basics/ultimate-beginners-guide-composting.htm
This article will help with the care of Magnolia trees: https://www.gardeningknowhow.com/ornamental/trees/magnolia/magnolia-tree-care.htm