Yes. They need water to carry all that foliage and sweet fruit. And lots of fertilizers for young tree's...you'res Jalilu not so much- it looks healthy,but still, it would help.
The shedding leaves means they need more water. I have an old 'Suebell' and years ago,every summer it was going too dry- a long story- but,now that's its getting some water and better care- its one of the nicest looking tree's around. Dark green.
Heck,I prune it 2-3 times a year all around to give me a nice canopy and room for Mangoes,Avocado's and more.

Thanks Stan. Always giving good advices! I envy you for your Suebelle sapote. The only varieties available here are Pike and McDill.

Changing subjects, I wonder if you could send me Manila mango pits. If you don't mind, email me to kfoukay@yahoo.com for further arrangements.

Yeah, white sapote seem to be a balancing act. They don't like too much water, or too little. Mine (SES2) has defoliated,
regrown, but in 5 years has not flowered.

Locally, Regans Nursery in Newark (ca) has tons of White Sapotes..all in great shape too. Very healthy looking and under full sun.
BUT- those other exotics? Still at only Sea Food city...the Carambola- I should buy that.
Jalilu..I will keep it in mind..But,I don' know if California to Morocco shipments is allowed. And,I have to really get them dry and clean. I once sent Papaya seeds to NZ..lol, I thought they were dry enough. They got there a mass of fungus and tossed out. My second try worked!