Flamboyant leaves yellowing and falling

Hello all ! :-)

Ever since I repotted my red Flamboyant tree from its original pot to a bigger pot, its bottom branches lose their leaves after yellowing (with brown spots) - photo link below...

The tree is still growing well, sprouting new branches regularly, but the yellowing, falling leaves are worrying me.

I'm in the south of France so I need to water the pot regularly but I try not to over water either...

I'm thinking my substrate mix is wrong. I added compost with fertilizer when I changed pots - maybe the mix is too rich...

What mix would you suggest?
Compost + earth + sand mix? Gravel too?
Any advice would be great - I don't want to make a mistake in my efforts to save this beautiful young tree..

 

Not a plant I've ever been very successful with so cant help much.
I know it needs high light levels and possibly a tropical climate, you might stand a better chance than me being in Southern France.
That leaf problem I have had, and seen before, in other similar related plants eg, Sesbania puncea.

Not worked out what actually causes it, you could look very closely at the undersides of the leaves with a lense, it could be Red Spider Mite.

Or it could just be down to unsuitable growing gonditions.
Maybe the repot stopped the roots growing.

Were there new white roots forming when you repotted? Or was the rootball dormant?

 

Thanks Pete.
Looking closely at the leaves but can't see if it's animal or chemical...
The root ball was dormant (repotted in autumn)...

 

Yep, so its been repotted since last year??
Has it made any real growth this year??

 

Looking at the pics again.
are you sure its Flamboyant tree, ie. Delonix regia.
The leaves dont look right.

It really reminds me of Sesbania

 

Not a good choice for pot growing. Possible causes are cool nights compared to the daytime temps, drying out, RSM or lack of nutrients (it grows best with plenty of organic material to simulate the forest floor conditions of its native habitat).

I grew one and by the sounds of it had as much luck as Pete. Caesalpinia is easier but not an alternative if Delonix is what you want.

 

It's Delonix alright.
Daytime 25 to 35°C, night time 20 to 25 on average.
It's been growing steadily since springtime and has doubled in height since last year (about 60 cm grown this year). Yes, repotted in the Autumn last year.
New branches sprouting every week!
But yellowing leaves with brown spots on lowest branch (which I usually prune off once it is bare)...
I'll be planting it in the ground next February (when our house is finished being built)... Until then trying to keep it healthy in a pot.

 

The Delonix I grew had tripinnate leaves.

Yours appears to be bipinnate

I know you are in the S. France, but I dont think the winters would be warm enough for Delonix.
But I could be wrong.

 

We're hoping so much that it will survive and flower here in the Mediterranean area. My wife has Mauritian roots and the red flamboyants are majestic over there!
We're going to plant it south-facing.
We'll give it all the love it needs hehe
But we want to be sure about the substrate mix (is that the term?)
Pozzolane + compost + earth from the new garden...

 

I've never seen a Flamboyant (Delonix Regia) with tripinnate leaves Pete, but I'm no expert...
Yes, it goes down to zero (celcius) maybe 2 or 3 nights per Winter season. I hope "she" will survive it if I cover the trunk and vase through the winter like I do with our other more tropical plants (banana tree, mango tree...)

 

OK, perhaps I got it wrong about the leaves then.

God knows what I was trying to grow