Apple tree leaves turning brown and yellow

[bergamotblack]

Hi everyone,

This is my first time caring for a garden and it has mature fruit trees in there which I am worried about killing with my brown thumb.

The apple tea produced a small crop of apples about 1-2 months ago and I noticed that some of the leaves near the top are turning dark and almost purple, with brown spots. Some leaves at the bottom are showing up with yellow veins. All leaves were dark green previously.
Apple tree leaves turning dark with brown spots apple tree leaves turning yellow near the main stem

The Mandarin tree procued a HUGE crop of fruits about a month ago and now its leaves are turning yellow.
Mandarin tree leaves turning yellow

I water regularly, gave the trees some seaweed solution a couple of weeks ago, and just fertilised with RichGro Black Marvel Fruit & Citrus Food Liquids. Not sure if I did the right thing? Any advice would be much appreciated!

Also, should I be spraying food-safe pesticides and how often should I do it? I have another orange tree which is currently fruiting and I am not sure if using pesticides will affect the orange tree as these 3 trees are only about a metre apart.

[MitchellMc]

Hi @bergamotblack,

Applying fertiliser was a smart move, as yellowing leaves often indicate a nutrient deficiency. Additionally, ensure you check the soil's moisture levels and adjust your watering schedule so the soil can dry out slightly between waterings.

Have you experienced any frosts or particularly cold days in your area recently? The purple colouration on the leaves might be a sign of cold damage. If you are seeing frosts it would be best to cover the plant with frost protection overnight.

Pesticides should only be used if you notice pests on the plants, and since it doesn't sound like there are any at the moment, it's best to avoid using them.

Here are some helpful guides: How to diagnose a sick plant, How to grow and prune an apple tree and How to plant, grow and care for a mandarin tree.

I'd tag a couple of our gardening experts, @Noelle and @mich1972, to see if they have any additional insights.

Please let me know if you have any questions.

Mitchell

[Noelle]

Hi @bergamotblack 

It is, of course, now winter and apple trees are deciduous, meaning they lose all their leaves at this time of the year. I wouldn't stress about leaves darkening or changing colour now as they are all going to drop anyway over coming weeks! While dormant (asleep over the cooler months), the tree is not going to take up or need much in the way of fertiliser - the time to feed it is in early spring when the flower buds are just showing colour and the new leaf buds are starting to unfurl.

What you do need to do is watch for any signs of disease discolouration on the new leaves in spring and take any remedial action needed at that time, not now.

[bergamotblack]

Gosh I feel like a silly goose now 😂 In my defence I grew up in a tropical climate with no winters... Thank you for putting it so kindly!