Non-flowering black locust tree?

runewoodman

I have two trees at the front of my house. One of them I am almost certain is a black locust (cream to white, drooping strings of pea-like flowers; short almost black seed pods with almost black seeds; younger growth has thorns and is quite soft, the wood is strong; in summer soft green leaves diffuse the sunlight providing a dappled cover of shade, cool and breezy on the ground beneath).

I am almost as confident that the other tree is also a black locust but it never flowers. Also, the new spring growth starts later and the leaves are a darker green than the flowering one.

I can't give you any photos because I've rented the house out, but both trees seem identical except for the few differences above.

The flowering tree is on the north east side of the non-flowering tree, but lower down the hill. The house is on north west side of the trees and on the south east side is a row of she oaks, about three metres away.

I can't say how old the trees are, but they were mature when I bought the house 5 years ago.

My question is, is it common for a black locust to not flower?

The trees are in Sydney, Australia.

Thanks in advance.

Rune