Hard to find plants can be easily started from seed
The ideal broccoli for a kitchen garden probably would behave like the fabled Hydra: For every head you cut off, two would grow back. Luckily, nature has already created broccoli that performs much that way. Unlike the modern hybrids you see in supermarkets, antique Italian varieties called sprouting broccoli develop small heads that mature at varying rates. That means a much longer harvest ― six to eight weeks ― of flavorful crops.
Italian green sprouting or Calabrese broccoli is the most commonly grown heirloom type. It develops a small main head followed by numerous side shoots. ‘Di Cicco’ and ‘Green Comet’ are two favorites. Spigariello broccoli doesn’t develop a central head, just lots of small buds and edible leaves. Use this versatile green raw in salads, in stir-fry dishes, or as a cooked vegetable.
Broccoli raab, like spigariello, has no head but lots of buds. All its edible parts ― buds, stems, leaves ― have a peppery edge reminiscent of turnip. Cook it the way the Italians do: Blanch briefly in boiling water, then sauté in olive oil with plenty of garlic. Nurseries seldom sell these as plants, but you can easily start them from seed.