This grower is fairly sure of this plant identification.
Pineapple mint, Apple mint, Round-leaved mint, Mint
Mentha suaveolens (Pineapple mint). This is a vigorous suckering perennial it grows to about 1m tall with felted grey-green apple-scented leaves.
They are very frost hardy, and need sunshine and rich soil with lots of moisture.
Grown for their aromatic foliage, which is both decorative and used as a culinary herb.