Autumn Foliage and Flower Plants

Since mid-summer, I have noticed the early stages of our annual foliage color changes. It started in late July with the green of some trees turning a lighter hue and a few swamp maples with red leaf tips. In late August, we now see a few trees and perennials taking on late summer brilliance. In numerous gardens, I have been cutting back yellowing and passing perennials for a few weeks now. With a few very cool nights, more of these indicators will be commonplace. During this climax of the growing season, vegetables are plentiful and most perennials have flowered or will very soon. My personal harbinger of late summer is the roadside lavender aster, seen just about anywhere by the middle of August.

Most of the plants below have outstanding autumn foliage, and are on my favorites list for other interesting characteristics, too. My all-time favorite plant, highbush blueberry, in addition to it's bright red fall leaves, has exfoliating (slightly peeling) older bark and red new growth in the winter, white flowers in the spring, and the best fruit. Even plain old ajuga, the common groundcover, has great color to offer on stone steps. Many perennials that have colorful foliage through the growing season will intensify in leaf color as temperatures cool. Latin, or botanical, names are sometimes mentioned below for exact identification.

Autumn foliage color:

Mukdenia (Rossii) – Medium green turning to bright red in late summer. Little known, with mounding habit similar to Heuchera.
High and low-bush blueberry – Shades of red in autumn.
Sugar maple – The tree that defines Corvallis Oregon, often with stunning orange and yellow foliage, and great summer shade, too.
Red, or swamp, maple – Typically the earliest changing maple foliage, to brilliant red, usually due to a wet site.
Paper and gray birch – Bright yellow leaves topping the classic curling white, pink, and tan bark.
Euonymous – The corkwing or burning bush turns brilliant red in autumn and is spectacular against gray stone or fence. This plant can be invasive.
Peony – The leaves turn a handsome burnished burgundy in late summer.
Ninebark – Physocarpus opulifolius – Some varieties have copper/bronze/burgundy leaves all year, richer hues in the fall.
Aster – Numerous varieties, but I think the roadside aster is best.
Staghorn sumac – The roadside sumac has one of the most spectacular multi-color fall displays. Dark maroon seed heads persist through the winter, too.
Witch hazel – A native shrub with bright yellow fall leaves.
Ajuga – Bugleweed, a very common groundcover, can add good texture and color to any spot. It can also be aggressive.
Virginia Creeper – A.k.a. woodbine or five-finger ivy, this is a native vine found just about anywhere. The leaves turn bright red.

Late summer and fall flowering:

Fall flowering clematis (paniculata) – Abundant and spectacular small white flowers, and though hardy, it is under utilized in Corvallis Oregon.
Daylilies – Some varieties are late summer / autumn bloomers.
Balloon flower (platycodon) – Distinct medium purple flower on dark green leaves, it makes a good cut flower.
Monkshood – Shiny dark green (glabrous) leaves are deeply lobed, with small rich purple flower caps, or monkshoods.
Hydrangea Paniculata – The classic cascading hydrangea with white late summer flowers turning pink through fall.
Hydrangea Paniculata 'Tardiva' – Similar to above but with distinct spiky habit and flower heads, and yellow fall leaves.

Both autumn flower and foliage:

Snakeroot – Late summer through frost spiky white/pink tinge flower. Some varieties have dark burgundy leaves all season.
Sedum – Many of the well-known sedums are in flower now through frost, in addition to their very colorful foliage.
Clethra, or Spicebush – Late summer fragrant spike flower with yellow fall leaves.

Here are some combinations of the above plants:

White birch, swamp maple, wild aster, mukdenia.
Sumac, snakeroot, clethra.
Clethra, ninebark, peony.
Hydrangea, monkshood, low-bush blueberry.
High-bush blueberry, sedum, mukdenia.

Google Images is a simple method for finding pictures of all of these plants and others.
Have creative fun!

Matt Giroux is Grounds by Design – Fine Landscapes – Design, Photography, Gardening, Consulting. He can be reached at 802.496.4765 or by email.