While we all enjoy the spring and early summer blooms each year, for many of our common shrubs that is their one big show. However in recent years new varieties have been produced which are repeat flowering and so add extra interest throughout the season. This article which I found on the Dengarden website describes seven of our old favorites that now have new hybrid varieties that will give a second flush of flowers.
Some of the most exciting garden introductions of recent years are reblooming shrubs. Much like hybrid roses, which can repeat bloom throughout the summer when cut back after flowering, there are now several shrub hybrids which are capable of the same thing. Instead of the typical peak of bloom in spring or summer alone, these plants keep right on adding color, fragrance, and enjoyment to the yard. Those who are planting new shrubs can consider these specimens.
Improved lilacsLilacs are actually small trees. Some are shrubby, but many older types can exceed 15 feet in height if left to grow. Their fragrant flowers traditionally come in pink, blue, lavender, and white, with doubles called ?French lilacs.? Long a staple of the late spring garden, they are some of the most hardy bloomers, growing even in US zone 3, which can reach -40 below zero Fahrenheit. Some recent rebloomers include the ?Bloomerang? series, available in pink, light and deep purple, and ?Scent and Sensibility? in pink. Boomerangs grow 4 to 5 feet tall, Scents 2 to 3 feet. ?Josee? is another new hybrid said to repeat bloom. Happiest in full sun ( that is, at least 6 hours of sun a day), they are very easily grown through the temperate parts of the country.
New hardy azaleasAnother plant traditionally associated with spring is the hardy azalea. Many evergreen azaleas are somewhat less hardy than the deciduous types. Their flowers flourish in US zone 6 (-10 below zero Fahrenheit) and south. These plants prefer partial shade and acidic soil. A blanket of mulch keeps their roots cool, moist, and happy. Rebloomers becoming available in the trade include the patented and trademarked ?Bloom-a-Thon? series, and ?Encore? series. Available in single red, white, lavender and pink doubles, they are said to provide 20 weeks of flowers. They have also been bred to be compact in habit. The lavender variety is the tallest at 4 1/2 feet when mature, with the white at 2 1/2 feet.