Looks to me like sunburn or more likely contact with some chemicals. Could it be that herbicides were sprayed outside in the yard? Some may have splashed on to those leaves.

I don’t use any chemicals in my yard so I don’t think it could be that. It’s hard to imagine that it’s sunburn either, given that during the winter months it’s not in full sun.

Thanks for the feedback folks. Our weather is fluctuating wildly lately so I’m eager for it to mellow out and stay consistent so the poor tree can try to put on new growth.

As requested here are more pics of the overall. I have no idea why the photos rotated, the originals are upright. Oh well.

The damage seems more extensive than I thought. With all that curling of leaves it could also be cold damage or may be a combination of various factors. Otherwise the plant seems OK and should leaf out when the weather warms up. For you it is much earlier than ours and you should be fine.

Another thing you want to check is of the soil is too wet for too long. It should be on dry side now since it does not need as much water - you have only a few working leaves left and the demand is less. Regular potting soil holds a lot of water and can stay wet too long.

The pictures show your Meyer's lemon outdoors, did you let it slowly acclimate to the light when you brought it outside, or did you just put it out in bright sunlight?

tropicofcancer - I'll check the soil next time I'm outside. I don't actively water it in the winter though. We have rain periodically that does the job well enough. I originally thought it was drought stress because of this factor - we had a period of time where the weather warmed up (almost to 80F) and didn't rain for over a week.

Ike - There is no acclimation because it's always outside. I never brought it indoors. This next winter I am going to though!

Well it does not look diseased to me and so all I can think of is environmental factors. So it could be a drought event in the past, too cold or rapidly fluctuating weather conditions. Those are the factors I can think.

Meyers are the most cold hardy of all lemons so I doubt that if it never got below freezing the cold has anything to do with it. Looks to me like it dried out during the week in the 80's that it did not get watered.

I was thinking the same thing as Ken and Tropic.

Also, I would quickly take a look at the roots to make sure they are not damaged somehow. Your soil mix looks like it is very condensed, not allowing the roots to breath freely which in turn can cause water and nutrient deficiencies.

Those kind of sudden temperatures can wreak havoc on my potted trees.

Thanks everyone! I'm definitely due to re-pot it so I'll look into giving it some fresh citrus-appropriate soil this week :)

I just thought I’d post an update here and thank everyone again for all of their help. The tree eventually dropped all of its leaves. I moved it into a larger pot and once it started showing signs of growth I gave it a serious pruning. It only lost 2 or 3 branches from cold damage. It now has loads of fresh baby leaves and seems quite happy!

Something I noticed, however, is that it’s sprouting leaves at the base of the trunk. I’m assuming it’s ideal to remove these?

If it is grafted remove any growth below the graft line, if its on its own roots then its up to you, if you want a bushy tree leave them, if you want a tree like tree take them off.