Perennial vegetables and herbs produce for at least three years. They don't require reseeding each year if planted in an undisturbed garden location. Often perennial vegetables and herbs require several years to reach full production. Many perennial herbs are grown in gardens and containers.
Asparagus spears emerge when the soil temperature is about 10 degrees Celsius. The optimal size at harvest is 7 to 9 inches. Asparagus plants grow from crowns or seeds and produce for 15 years or more.
Rhubarb stalks are used in pie, bread, cake and sauce recipes. The red or green stalks are edible while the leaves are toxic. The cool season plant grows well in the northern areas of the United States. Rhubarb grows from crowns.
The lemony flavoured sorrel leaves are used in salads, soups and sandwiches. Individual leaves are harvested in early spring when 4 to 5 inches long. Sorrel is grown as an annual in cooler climates and as a perennial in warmer climates.
Ground horseradish roots provide a pungent sauce for roast beef. The hardy plants grow 2 to 2.5 feet tall. The roots are dug after the first hard fall frost and before new plant growth appears in the spring. The plants grow from root cuttings and spread vigorously.
Radicchio and Garlic
Heads of white and red radicchio are a major ingredient in Italian salads. Garlic, a popular seasoning, grows in bulbs. Both types of vegetables are perennials but are usually grown as annuals.
Lavender and lemon verbena provide a basis for potpourri. Catnip is a favourite herb for cats and provides leaves for tea. The remainder of the perennial herbs season soups, casseroles, meat and sauces. This list includes chives, French tarragon, mint, oregano, rosemary, sage and thyme. Perennial herbs grow well in pots and containers. The individual leaves or stems are harvested as needed for recipes.
- University of Illinois Extension: Gardner's Corner: Growing Cool Season Vegetables
- University of Minnesota Extension; Growing Rhubarb and Sorrel in Minnesota Home Gardens; Jill Mackenzie; 2009
- University of Illinois Extension: Home Hort Hints; Unusual Vegetables
- Virginia Cooperative Extension; Herbs; Diane Relf, et al.; May 2009