After the first frost in the autumn kills the leaves, the root is dug and divided. The main root is harvested and one or more large offshoots of the main root are replanted to produce next year’s crop.
Horseradish left undisturbed in the garden spreads via underground shoots and can become invasive. That is a good reason to plant in a contained area. I have had mine in a half wine barrel for years.
The improved Green Globe Artichoke variety yields over a long period of time, fall or spring, depending upon location. Can be pretty in landscaping with its fountain-like look of silver-green foliage. Flowers great for dried arrangements. Mature height is 3-4 ft. with 5-6 ft. diameter. Cold hardy to USDA Zone 5.
The Jerusalem artichoke can be produced throughout the United States. However, the plant is better adapted to the northern two-thirds of the country than the southern third. Often used for pickling purposes. Fresh tuber tastes like a water chestnut and is used in salads. Tubers can also be cooked like potatoes. The edible portion is the tuber or swollen end of an underground stem, which in some respects resembles a potato.
Here is a video from Peaceful Valley http://www.groworganic.com about growing and the fall care of horseradish, artichokes, asparagus, Jerusalem artichoke, and rhubarb.
As you can see, these vegetables are easy to grow and bring many rewards to the garden and a bountiful harvest with few amendments - just add compost and mulch well.