Plum and pear tree issues

[OhRene]

I have two patio plum and pear trees. They were sold to go into planters on a patio so it shouldn't be that where the issue lies hopefully. The poor buggers aren't doing very well. I've attached a couple of pics of the plum tree here:

The app is now being an arse and won't let me add more photos to the possible selection so I can't show the pear.

Could I be overwatering maybe? Under watering?

Looks like a fungal problem, I'd spray with fungicide. Does the pear have brown or orange spots on leaves too? If so that's the same, I think.

Or if there's visible beasties (usually aphids) then an insecticide instead.

Make sure you are feeding with seaweed regularly and watering enough.

What size pot are the trees in? If the pot is small it could be that the soil is drying out too quickly. Is it in full sunlight? I'd move it to a shadier area until the trees are more established. I'd guess a mix of overwatering and under watering is affecting growth and causing the brown leaves. Also don't leave the pot sitting in water.

If you unfurl the leaves are there any creepy crawlies or cobweb type deposits there?

And also feed with seaweed regularly as PP said.

The pots are pretty large but not huge and they are in full sun. I might move them round to the back garden where there's some shade during certain points of the day just in case. No sign of any bugs. I've been checking regularly since my new Cherry (in the same pots and bought with these guys) was nearly killed by aphids. I'd to spray it and keep it in a mini greenhouse so no bees got to it.

I'll give them a spray of a fungal treatment and see how it goes. If not I'll consider planting them out the back and I'll start me an orchard instead. Apple, cherry, pear and plum trees in pots never did seem like a doable idea to me but I thought I'd try.

And I'll buy some seaweed feed.