I dug up my yellow potato onions and was surprised to find almost 40 bulbs. I first wrote about them in September 2016, when I received the shipment from Southern Exposure Seed Exchange. I planted the original 15 bulbs in the fall in very loose soil, high in organic matter. This spring, green stalks grew so that by summer there was green tubular foliage, similar to scallions. By the end of June, I could see bulbs clustered at soil level, as if emerging from the deep. The green stalks were bent and falling over so that when it was clear that the stalks were dying, I dug up the bulbs in the beginning of July.
Potato onions are a type of multiplier onion called Allium cepa var. aggregatum. They multiply at the base by making more bulbs. They are not as large or as pungent as onions we get at the grocery store. Within the same species are shallots, which also multiply at the base but are milder, can be eaten raw, and are round or bullet shape. The Egyptian walking onion is another type of multiplier onion, a different species called Allium cepa var. proliferum. The difference between potato onions and Egyptian walking onions is that potato onions do not create bulbils at the top. The Egyptian walking onions create bulbs in the ground and bulbils at the top; therefore, are “proliferate.”
In my Virginia garden, potato onions are planted in the fall, dug up in the summer, cured until fall, and then some are re-planted and some are eaten. Thus they are “perennial” because they will exist in the garden every year. In the 1800’s, they were very popular because they were a constant source of onions, they stored for a long time, and they propagated easily. People just passed them along to neighbors and family. Now they are considered an heirloom. Very few seed catalogs sell them and you probably will not see them in your garden center.
Like other onions, potato onions have to be cured in order to extend their storage time. Bulbs should be in a shaded, warm, dry, well-ventilated area for a few months. I could slice up the large ones now and cook them or just let them cure if I want to use them in the winter. In the fall, I will plant the smaller bulbs and harvest again next year in July. It’s a perennial cycle but I am looking forward to sliced yellow potato onions in butter and parsley over broiled trout, with green beans on the side.