How Long Do Perennials Last?
The life spans of perennials vary with each species. Most last for a several years. Peonies go happily for many decades! Delphiniums increase in size steadily for about 7 years and then slowly become weaker and need replacing. However, because their root base has been increasing, root division of perennials allows the plants to be divided and new younger roots to be used to replace the parent plants. Thus, their lives can be extended almost indefinitely. Perennials in the Pacific Northwest All our perennials are grown and stored outside. They need no special conditions, being hardy at our zone (approximately zone 8). You need have no concern about the survival of our plants throughout the year in this region.