Why Pineapple Mint Is Not Available as Seeds

Why is pineapple mint only available as plants and not seeds? Is it also a perennial from the Mentha family of mint?

Few of the mints come true from seeds. The mints (Mentha species) are a promiscuous lot. They crosspollinate among themselves with abandon resulting in an almost infinite range of varieties. As hybrids they are either infertile and can't produce seeds or they do not produce seeds that grow plants like the parent. Even the familiar peppermint is recognized as a hybrid that does not produce seeds. If you see peppermint or spearmint seeds offered be warned that these will not produce anything like the true mints we know and love.
Pineapple mint is a hardy perennial. The botanical name is Mentha suaveolens 'Variegata'. It has a refreshing scent that is suggestive of pineapple, but it is not as strongly pineapple-scented as pineapple sage (Salvia elegans).