If you're looking for hardy, no-care, "Plant and Forget" spring flowering bulbs, look no further - load up on Muscari. These bulbs are so winter hardy and easy to grow that no garden should be without them.
The Hardiest of Hardy Perennials. Generally speaking, a plant is classified as a perennial if it can survive to Zone 7. Above that range, plants become tender perennials or annuals. For the purpose of this article, we will only consider the "hardiest" of hardy perennials, plants that are hardy to Zones 4 and lower (or higher in latitude). The plants on this list are definitely tough enough to survive your area's worst winters.
Allium ‘Millenium’ is a versatile perennial for a sunny garden because of its compact upright habit and resistance to all types of pests. It is also drought tolerant and loved by butterflies and bees. Though the fragrant blooms are very attractive in midsummer, the seed heads are the real floral feature. They last for several months, providing interest in the garden until late winter.