There is a Cure for the Summertime Blues

Like some television commercials say about their product, “But wait, there’s more”, this statement can also be said about flowering shrubs. Just because spring is over, it does not mean there is no more color in the garden. Yes, there are herbaceous perennials that bloom in summer, but there are some fabulous flowering shrubs that also shine during the dog days of summer besides roses and Japanese spirea. Here are three of my favorite larger shrubs with big landscape impact.

Roses ('Graham Thomas') are not the only shrub that blooms in summer
Roses (‘Graham Thomas’) are not the only shrubs that blooms in summer

Bottlebrush buckeye (Aesculus parviflora) produces flowers in the northern U.S. in early July. The white flowers are especially unique and are borne on large, 8-12” long panicles rising far above the leaves. The flowers resemble a large bottlebrush and are often home to visiting butterflies and bees.

Bottlebrush-like flowers
Bottlebrush-like flowers
Bottlebrush buckeye in full bloom
Bottlebrush buckeye in full bloom

In autumn, the foliage turns bright yellow early in the season. This large, spreading, suckering shrub needs a lot of space to grow reaching 8-12′ tall and 12-15’ wide at maturity. It is native to the southeastern U.S. and performs best in rich, moist, well-drained soil, but is adaptable to most soils and pH. Bottlebrush buckeye grows in shade to partial shade and out of the hot afternoon sun. Unlike its tree relatives, this Aesculus species is not susceptible to powdery mildew, leaf blotch or leaf scorch and is hardy to zone 4b.

 ‘Nordine’ smokebush (Cotinus coggygria ‘Nordine’) is another large, wide-spreading, upright shrub that grows 10-15′ tall and wide. It produces purplish-red new leaves throughout the growing season that later turn dark bluish-green. When crushed, these leaves smell like a combination of radishes and oranges.

'Nordine' smokebush in full bloom
‘Nordine’ smokebush in full bloom

The individual flowers are not particularly attractive, however, that quickly changes. The hairs on the individual stems of the 6-8” long flower panicle elongate and turn a wonderful smoky pink to purple color that lasts for many months. The orange-yellow to purple fall color is equally appealing.

Hairy flower panicles of 'Nordine' smokebush
Hairy flower panicles of ‘Nordine’ smokebush

The species is native to southern Europe over to central China and the Himalayas. This particular cultivar of smokebush is hardier than other purple-leaved cultivars of smokebush and should reliably flower in zone 4b each year. It is able to withstand most soils and pH, full sun, drought, and urban conditions. Deer don’t seem to bother this plant. Maybe the smoky appearance of the flowers scares them away?

‘Limelight’ panicle hydrangea (Hydrangea paniculata ‘Limelight’) is one of the best flowering cultivars of panicle hydrangea. The flower panicles are huge, up to 6-10” long starting lime-green and eventually turning all white. As the flowers fade, they turn pinkish to brown from fall through winter providing multi-seasonal interest. The added benefit of this cultivar is that the flowers are borne on strong stems that are held upright, so flowers will not flop over like some other panicle hydrangea cultivars.

Green flowers of 'Limelight' hydrangea before they turn white
Green flowers of ‘Limelight’ hydrangea before they turn white

‘Limelight’ hydrangea is smaller than the species growing 6-8’ tall and 5-6’ wide at maturity with an upright, spreading form. The species is native to Japan and China and hardy to zone 4a. Panicle hydrangea does well in an organic, fertile soil, but is quite adaptable to soil and pH. It requires full sun for the best flower display and moist, well-drained soil, but it is not as finicky about soil moisture as some of the other species of Hydrangea.

'Limelight' panicle hydrangea in full bloom
‘Limelight’ panicle hydrangea in full bloom

When designing a landscape, incorporate a variety of trees, shrubs and perennials to insure continual bloom throughout most of the growing season. These three, non-invasive shrubs are all available at most nurseries and garden centers. If you have not tried one of these beauties yet, plant one or all three in your yard. You will be happy you did.

–Laura Jull, a.k.a. The Lorax

Published by

Laura Jull

Associate Professor and Woody Ornamental Extension Specialist in the Dept. of Horticulture at University of Wisconsin-Madison

3 thoughts on “There is a Cure for the Summertime Blues”

  1. Hi and welcome to the blog!

    Thanks for the suggestions. I’ve never see the buckeye growing and it certainly looks beautiful. Does it need any support to stay upright during rain and storms? I dislike staking plants passionately (even though I do it for a few select favorites.)

  2. No, bottlebrush buckeye does not need support, nor does the other two shrubs featured. The flowers are held upright and the plant does spread via suckers. It is not for the little garden. Hope this helps,
    Laura

  3. Laura, I was wondering if you have ever noticed a difference in performance between b-&-b Cotinus cvs. and those grown in soilless media. It is hard to find smoketrees in Atlanta, especially ones that do well other than ‘Grace’ which is overplanted and rangy. Usually, only ‘Grace’ is available in pots, and I have noticed problems with varieties that are b-&-b and then planted in our clay.

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