Mango tree no lateral branches?

Anyone explain why my mango wants to shoot straight up but will never grow lateral branches. Leaves grow but they fall off and never eventuate into branches. I’ve had mango trees before and this never happened. It’s Kensington Pride, Perth WA. It’s growing where a dead peppermint native tree used to be; wondering whether the roots having hard time but seems healthy otherwise. Been there 2yrs now.