Asparagus
Asparagus is not only delicious, it is extremely long-lived--an asparagus bed can last over a century. Provide good drainage, mulch yearly, and enjoy the luxury of asparagus for a month every spring. Plants must size up and get a good root system before they can stand harvesting. There's not much else to it except patience. Plant on cutting your first crop the 3rd year. (My hard-won advice on this score: Do it now. If you put it off, in three years you still won't have asparagus.) Male plants have fatter spears, and you can weed out females (the plants with red berries) if desired. 20 seeds
Site a bed where it has good drainage and warms up fairly early in spring. In hot-summer climates, the east side of deciduous trees is great--sun comes through the bare branches for an early warm-up in spring, there is afternoon shade is summer, and the trees automatically mulch your asparagus bed. Cooler areas will want to have full sun all year. Good drainage is key. If you have heavy clay or live in a very rainy climate, be sure to add lots of compost and some rocks under the plants. Mulch is also key, to keep grass and weeds from invading the beds and weakening the plants. Seedlings will be both male and female. All that can wait, though, because these perennials are started in pots and planted out after frost. The little plants start slow, but develop big fleshy roots. Feed them well so they size up before winter.