I'm new to this! Not sure what I'm growing or where I'm going wrong... I have several of these trees just about 10 month old. About half are OK and looking good, the other half are wilting and the leaves are dropping off.
I have used feed and think some are suffering from burn.

They are currently in a warm conservatory. Watered when needed.

I just need to know whether they shed leaves? What type are they, how best to care/feed?

Any help would be awesome

Any help would be awesome

I am not an expert, so I can only give you my best guess. I would recommend hoping/waiting for one of our more experienced posters here.

To me that looks like a Flame Tree, if the leaves kinda fold up at night (looking at the branch in the back/top/middle).

My other guesses would be Brazilian Rosewood, or Blue Jacaranda. But I don't want to mislead you, I would see if someone who knew better could lead you the right way as I am still learning and could definitely be wrong.

No! That for sure doesn't look like a flame tree as you can see that the tips are kind of pointy, it looks like a blue jacaranda (I'm growing a few of these from seeds myself, although they're from my backyard). You should not keep them in a warm climate! Keep them cool until they're about 1.5 years old. What hardiness zone are you in? They best grow in the SoCal-Arizona side in the US. (Though you may not be in the US.) The hardiness zone they thrive in is around 9a-9b. (Which is where I live) You should stop watering them on a schedule, water right when the soil feels slightly moist. It looks like the leaves are drying and getting fried, keep a humidifier next to it to prevent leaf drying. (though it is not enough to do that) Give it a thorough watering now (Like right now, when you read this message) because it is probably already half dead. Do the bark scratch test, where you remove a layer of the bark to check the colour:

If it's green, it's alive.
If it's brown, probably dead.

These trees are semi-deciduous, in other words, they lose their leaves for a very short period of time in the winter. Not during this time. One time, I took a cutting off of the Jacaranda tree in my backyard, but it's leaves fell off after a few days. (Because of lack of water.)

Long story short: This tree is a jacaranda, these are semi-deciduous. The leaves have dried up, give it a thorough watering, NOW.

I hope that this helps, sorry for the long answer!

Oh, and a short note: Keep them between 70-80º F (21-31º C) and give them plenty of sunlight, but keep them indoors until they are 1.5 years old.

First you should focus on identify this tree...
By the look of it, I would tell you it's bud really looks like a Flame Tree, but the leaves don't look that much...

And well, I can tell you for sure that this is not a Jacaranda either...

Do you have any picture of the seeds?

Reference:
Jacaranda leaves' very tip are always single and pointy, never doubled...

My guess, is that this is a Leucena as we call here.
(Leucaena leucocephala)

But yes, could be another mimosoideae

Brother, you have better attention than me.

I just noticed that blue jacaranda tree leaf tips are single-pointed.

Could be a flame tree... But may also be Leucaena Leucocephala.

Maybe the OP can confirm what species it is.

NEVER do a scratch test. it does NOT tell you ANYTHING.