Locust (Robinia), fam. Fabaceae.
Unlike Black Locust, the rest species possible in Kyiv, among which are New Mexican Locust (Robinia neomexicana), Clammy Locust (R. viscosa), Luxuriant Locust (R. luxurians), Bristly Locust (R. hispida), have pink flowers, and their inflorescences are covered with hairs (sticky in the case of R. viscosa), the leaves are sharpened instead of oval.
All these species are much more rare, and start blooming somewhat later than false acacia, but then they bloom second time – in late summer. The flowers have weak smell.