Most perennial gardeners dream of finding the perfect plant, a holy grail that sporst constant, abundant flowers and returns effortlessly each spring.
Of course, there are good reasons the prize is so elusive. It takes a lot of energy to produce flowers, and any plant that can keep it up well into fall will be challenged to store enough reserves to carry it through our long Michigan winters. This can make them the James Dean of the garden — handsome heartthrobs that live fast and die young.
A workable compromise is a balance between long bloom and longevity. Some of my favorites.
Pincushion flower Butterfly Blue and Pink Mist (Scabiosa columbaria hybrids) are blooming machines. These plants have a 3- to 4-inch mound of foliage and wiry 12-inch stems topped with blue or pink flowers. They start blooming in June, and will continue through the summer. Papery seed heads are ornamental in their own right and can accumulate for several weeks before they start to take away from the impact of the flower display. At that point I take a pair of shears and snip the stems down to the next good bud and off they go again. They grow best in full sun and well-drained soil.
If you have shaded conditions, yellow false bleeding heart (Corydalis lutea) is an outstanding performer. It starts flowering in May, and continues until frost. Plants form eight to twelve inch mounds of fine spring-green leaves topped with sprays of petite yellow flowers. They reseed themselves anywhere there is a spot of open soil in the garden — opportunistic to be sure, but not aggressive, as they will not push any other plants aside. This continuing renewal and abundance of new plants ensures fresh, vigorous growth and flowering, and it may in fact be a succession of different plants that carry the bloom for the full season.
Many long-blooming perennials start with an initial heavy bloom, and repeat less profusely through the summer. Bloody cranesbill (Geranium sanguineum) is one of the best, with its mounds of clean green foliage topped with magenta flowers. Unlike some of the other perennial geraniums in my garden, it does not fall open in the center when in full bloom. No need to trim spent flowers to keep it blooming, either. It reaches 12 inches tall and grows well in full sun or half shade.
Plants that bloom for six to eight weeks are more plentiful, and tend to be longer lived. The best of these are also sought by hybridizers, who do their best to develop varieties with an extended flowering season. This breeding work sometimes shortens longevity, or varieties may not produce fertile flowers — considerations as you choose plants for your garden.
Coneflower (Echinacea purpurea and hybrids) is an excellent example. The standard species starts producing its purple or white flowers in early July and continues through fall — if you trim the first crop of faded blooms before they go to seed. Today’s overwhelming assortment of hybrids offer unusual flower forms and color blends, and colors in myriad shades pink, purple, yellow, orange, red — and flower earlier and more abundantly, even if we’re slow to trim those old flowers. Choose from a range of plant sizes and shapes, including petite, compact forms perfect for garden’s edge, or towering specimens that rise from the center.
Black-eyed Susan (Rudbeckia hirta) and balloon flower (Platycodon) can be tricky to sort out in the garden center. Some hybrids bloom so early and long that they behave more like flowering annuals, and may be sold as such, though technically they are perennials. Encourage these to reseed in the garden to improve chances you’ll see them again next season.