I have 2 young apple trees approximately 2 years old. They were planted last spring and have been growing well. One dwarf mac, and one dwarf honeycrisp. Both trees in the past few weeks have discolored areas on their leaves on this years growth. They have not been fertilized this year, but mulched this and last year. Is this coloration just due to new growth or is this a deficiency? If so, what am I likely missing?
See attached images.
That could be a deficiency, but I am not sure which one. Perhaps a combination.
Mulch is not fertilizer. It may contain the elements the plants need, but before the plants can benefit the mulch needs to be broken down by macro and microorganisms from worms to fungi.
Each of these takes some of the elements, leaving less and less for the plants. By the time the elements originally present in the mulch make it to the plant they could have passed through several organisms, and a lot of the original material is lost. It also takes time.
I would rake back the mulch, apply a complete fertilizer and soak it in, then put the mulch back. Read the label on the fertilizer, and apply it as often as it says, though maybe not as much as it suggests.
Our yard where this is planted is mostly clover, so I'm thinking that nitrogen is not the problem, and am guessing there's a different mineral issue since both trees are affected. I should probably just get a soil test to know what to supplement. I know that boron has a similar discoloration in citrus, but can't find information relating to apples.
http://homeorchard.ucanr.edu/
Here is a starting place for a lot of info about growing fruiting trees in the garden. I know it is a west coast site, but nutrient deficiencies look the same all over.
Wow! Thanks for reviving this thread and posting this answer.
