Spiraeas

Spiraeas are show-stopping shrubs that enhance the midsummer garden.

It’s easy to have a glorious garden in late spring and early summer, when all the classics from peonies to iris are in bloom. As the heat settles in, though, these early bloomers fade, often leaving the garden dull through midsummer, in the interval before fall arrives with its colorful fruits and foliage. With a little skill, though, you can re-energize your summer garden. The midsummer bloomers are less well known than those of spring and early summer, but they do exist. It’s just a matter of knowing what to ask for at the nursery.

Shrubs are the backbone of most gardens, lending structure to the landscape, as well as serving as a backdrop for perennials and annuals. There are a number of choice shrubs that come into bloom in midsummer. Of these, I prefer to focus on native species, as they serve not only to delight the eye, but also to feed pollinators and other wildlife.

Perhaps the most dramatic of these is the sweet pepperbush (Clethra alnifolia). This medium-sized deciduous shrub makes a compact and rounded mass of rich green foliage, typically 3 to 6 feet tall and wide. Sweet pepperbush flourishes on average to moist soils in full sun to partial shade, and in July to August covers itself with upright spikes of perfumed, white flowers that are magnets for butterflies and other pollinators. Come fall, this shrub’s leaves turn an attractive yellow to golden brown. Hardy zones 3-9.

Other star performers of midsummer are a pair of native spiraeas: the meadowsweet (Spiraea alba) and the steeplebush (Spiraea tomentosa). The meadowsweet makes an upright shrub to four feet tall, preferring moist, well-drained soils in sun to partial shade, and blooms typically in mid-July, with small white to pale pink flowers borne in cone-shaped clusters 3 to 4 inches long. Hardy zones 3-7.

Steeplebush is a little later to flower, coming into bloom in late July. It’s broader than its cousin, reaching a height of 2 to 4 feet with a spread of 3 to 5 feet. Steeplebush’s blooms are, as the name suggests, exhibit spire-shaped clusters to 8 inches long and are pink to rose purple, and attractive to butterflies. It tolerates a wide range of soils, thriving especially in acidic, moist to wet ones in full sun, although it tolerates light shade. Hardy zones 3-8.

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A native shrub that flourishes in drier soils is the northern bush honeysuckle (Diervilla lonicera). Reaching a height of 2 to 3 feet and a spread of up to 4, this shrub features trumpet-shaped, yellow flowers into July in the North Country; it’s hardy as far north as zone 3. Adapted to full sun or partial shade, this shrub is an important nectar-source for bumblebees. Its shiny, green foliage turns yellow to orange, sometimes red, in the fall.

A dramatic, summer-blooming native perennial to weave in around these shrubs is Culver’s Root (Veronicastrum virginicum), whose imposing stalks tower to a height of as much as 5 feet, bearing slender, upright, 9-inch stalks of white to pale blue colored flowers in July and August. Preferring full sun, it grows best on medium to moist, well-drained soils, and is hardy to zone 3. Butterflies flock to this plant when it is in bloom.

Another summer-blooming native perennial is the large coneflower (Rudbeckia maxima). An outsized presence in the garden, this perennial can reach a height of 7 feet with a spread of 4, and its bluish basal leaves can measure 24 inches long by 10 inches across. The brown-centered, yellow flowers attract monarch and swallowtail butterflies, as well as hummingbirds. Best in full sun, this plant tolerates light shade and thrives on moist to dry, well-drained, average soils. Hardy to zone 4.

One final entry in this portfolio of summer-blooming natives is the so-called “sneezeweed,” Helenium autumnale. Growing to a height of 3 to 5 feet with a spread of 3 feet on the rich, moist soils and full sun it prefers, this perennial bears its 2-inch, bright yellow daisy-like flowers later in the season than the other species described here; sneezeweed typically blooms from August into October. Hardy to zone 3.

A garden based on these natives will be as beneficial to wildlife and pollinators as it is colorful. It can also provide an environmentally beneficial backdrop to more traditional summer bloomers such as shrub roses, dahlias, and summer-blooming annuals. There should, after all, be room for all kinds of pleasures in a well-planned garden.

Be-a-Better-Gardener is a community service of Berkshire Botanical Garden in Stockbridge. Thomas Christopher is a volunteer at Berkshire Botanical Garden and is the author or coauthor of more than a dozen books His companion broadcast to this column, Growing Greener, streams on WESUFM.org, Pacifica Radio and NPR and is available at his website, thomaschristophergardens.com/podcast.