DEL.ICIO.USERICA GLASENER
Tall, late-blooming perennials add drama
Thursday, September 04, 2008
I recently visited with George Sanko at the Georgia Perimeter College Botanical Garden in Decatur. His passion for plants is contagious, and it’s always invigorating to talk with him about whatever is happening in the garden during a particular season.
On this late summer day, I was struck by how many perennials in bloom or about to bloom reach 5 feet high or higher. I have always liked tall plants; dwarf selections are OK, but sometimes bigger is better! Clumps of tall perennials can help anchor the herbaceous border in a large garden, while at the same time they can make a small garden seem larger. A well-placed rudbeckia nitida “Herbstsonne” or ironweed, vernonia noveborcensis, adds late-season color and drama to the garden.
Erica Glasener / AJC Special
Shining coneflower is a sturdy perennial that produces masses of yellow flowers with green cones in midsummer and again in fall.
Erica Glasener / AJC Special
Joe-pye weeds are perfect for a border, with coarse green leaves and heads of rosy-purple flowers in late summer. This native may not be refined enough for every garden.
Botanical name: Rudbeckia nitida, "Herbstsonne"
About the plant: This sturdy perennial produces masses of yellow flowers with green cones in midsummer and again in fall. It grows to 7 feet high and is a favorite of monarch butterflies.
Use in the garden: Plant this coneflower at the back of the border or in the middle for added height. Combine it with ironweed, ornamental grasses, salvias and verbena bonariensis.
Planting and care: Plant shining coneflower in full sun in well-drained soil.
Source: Scottsdale Farms, 15639 Birmingham Hwy. (Ga. 372), Alpharetta, GA 30004, 770-777-5875
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In my garden I grow “herbstsonne” with purple-flowered salvia guaranitica and the airy lavender-flowered verbena bonariensis, which I let weave in and among the other plants.
Joe-pye weed, eupatorium, is a native that may not be refined enough for every garden, but its late-season blooms are welcomed by many butterflies and bees.
Many of these long-legged beauties are “good doers,” too. By this I mean that they are generally pest- and disease-resistant, drought-friendly and adapt to a wide range of soil types. Most of them won’t require staking, as long as the soil is not too rich.
On the day I visited the GPC botanical garden there were several silphiums in bloom, including silphium gracile, also known as Slender Rosinweed. This tough guy grows close to 7 feet high and produces yellow daisylike blooms from late summer to early fall. Combine it in a naturalistic style garden with other late bloomers like the mountain mint, pycnanthemum virginiana, and butterfly bush, buddleia davidii, a combination guaranteed to attract butterflies to your garden.
A duo I like for late summer and early fall is ironweed (it has purple flowers) in combination with hibiscus coccineus, the rose mallow with scarlet blooms. A bonus is the hummingbirds, which are attracted to the hibiscus.
Another group of late summer and fall bloomers are the different species of helianthus, or sunflowers. Helianthus trachelifolius, woodland sunflower, a native of the eastern and central United States, produces masses of yellow flowers in late summer, as does helianthus grosseserratus. Both of these species grow to 7 feet high and like full sun and a light, rich soil. Later in the season, the giant whorled sunflower, helianthus verticillatus, blooms on stems that reach 10 to 12 feet or higher. Not quite as tall, reaching 8 to 10 feet, the giant pale yellow sunflower, helianthus giganteus, makes a statement with its masses of yellow sunflowers in early fall.
Gardeners may not be familiar with the stiff goldenrod, solidago rigida, which blooms in fall, too. Its showy yellow flowers attract bees, butterflies and hummingbirds. The stiff goldenrod also provides a nectar source for monarch butterflies. A drought-friendly species, it likes well-drained soil. Combine it with one of the ironweeds and late blooming sunflowers.
There are many different asters for fall, but the tallest one I know of is aster tartaricus, which produces masses of pale lavender daisies with yellow centers atop 6-foot (or taller) stems in October to November. I have grown this aster in several different gardens and have never had to stake it.
Erica Glasener is a horticulturist and host of HGTV’s “A Gardener’s Diary” at 7 a.m. Thursdays.
