Jerusalem artichoke- also called the sunchoke, is grown for its tubers. They can be used in most of the same ways as a potato, although they tend to be lumpier. The biggest benefit to these is they are a phenomenal substitute for potatoes for diabetics. They do not cause the spikes in blood sugar that potatoes do. They multiply underground, so as long as you do not dig out all of them (which is VERY hard to do anyway), they will come back year after year. If you want to keep them from taking over, digging a hole for a baby pool and tossing one in can keep them contained a little better.
Walking/egyption onion- These onions have little baby onions, called bulbils that prolifically grow on the top of the plant. They can be used like any baby onions and regular onions, and have a stronger taste. The stalks can be used as a spice or in salads and have an oniony taste also. Do not pick the big onion if you expect them to come back the next year.
Siberian pea shrub- this little shrub produces lentil-like seed, pods, and flowers, all of which are edible. They are fairly mild and can be used in many ways.
Ground nut- yes, the peanut. as with all root vegetables, you can not pull out all of the peanuts, or they will not grow back. Aside from their uses in candy and as a snack, they can be ground into flour, made into milk, oil, and of course, peanut butter.
Potatoes also work great as a perennial. As with the others, just don’t harvest all of them, and they should sprout back next year from the eyes of the remaining potatoes.
Using these types of plants in your garden not only provide food, but also save you time and money. This is very important if you have a big family and bigger bills.