Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
9/12/02
FOR IMMEDIATE RELEASE
Contacts:
Maria Ball, Reiman Gardens, (515) 294-2710, mball@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Spring Scent from Sweet Autumn Clematis
By Linda Naeve
Extension Coordinator
Reiman Gardens
Throughout the year, each season yields familiar plant fragrances. For example, some homes are filled with the strong scent of forced paper white narcissus in the winter months. The sweet smell of flowering crabapple trees and lilac perfume fills the fresh spring air. In the summer, lilies and roses dominate with their heady fragrances. The smells of dried leaves or chrysanthemums make us think of fall. This week's Reiman's Pick - 'Sweet Autumn' clematis, Clematis ternifolia - brings back the sweet smell of spring in the fall. To some gardeners, its scent resembles the fragrance of hawthorn blossoms while others believe it smells more like vanilla. But everyone agrees s that its fragrance is sweet without being overpowering.
'Sweet Autumn' clematis is an extraordinary plant in the garden. It is hardy to zone 4 and rivals Jack's beanstalk with its rapid, vigorous growth. If given support, the shoots will climb rapidly - up to 20 to 25 feet in a single season. If it runs out of room to climb, it will form a mound of vines over the top of its support, onto the roof of a house or into the branches of a nearby tree. The climbing ability of 'Sweet Autumn' clematis is credited to its leaf petioles, or leaf stalks, that wrap around a trellis or any upright structure it can climb. It can quickly cover a trellis or arbor with foliage in the summer, and in late August and early September it puts on a spectacular show with thousands of small white, star-like flowers. This profusion of flowers looks like white foam. After the flowers fade, silvery, plume-like seed heads decorate the vines.
Except for its foliage, long vines and fluffy seed heads, 'Sweet Autumn' does not share many characteristics with others in its genus. It blooms much later than many clematis species and the flowers are much smaller at only an inch to an inch-and-a-half in diameter. It also seems to have a bit of an identity crisis in the literature and nursery industry. 'Sweet Autumn' clematis, has been called C. maximowicziana, C. paniculata, C. dioscoreifolia and Clematis ternifolia - the latter being the most recent, correct name. It is not a new species to gardens, either. It has been grown in Europe since the 1770s, when Thunberg, a Swedish botanist, sent it from Japan.
The flowering habit of 'Sweet Autumn' is also a bit different from other clematis. It is considered a "group 3" type clematis which means that it produces flowers on the current season's wood. This is an important characteristic to know about clematis at pruning time. For example, some clematis bloom on previous season's wood so they should not be pruned until after the flowers fade. 'Sweet Autumn' clematis is just the opposite. It is easily and best pruned in early spring by cutting last year's stems six to 12 inches above the ground. Don't be alarmed by this drastic pruning. It is a vigorous grower and by mid-season will be covering the trellis again.
Plant clematis early in the spring in a well-drained sunny location where the roots are shaded and kept cool. A layer of mulch around the plant will keep the soil moist and cool. The young shoots can be directed to grow up a trellis, on a tall pergola, or even on support posts of a deck or balcony. Don't erase 'Sweet Autumn' clematis from your list of "must have" plants simply because you don't have a trellis or arbor to grow it on. It can be grown through and over a large shrub, but its growth must be monitored and contained to ensure that the clematis does not overwhelm the shrub. 'Sweet Autumn' is so vigorous that it can simply sprawl along the ground as a dense ground cover to hide old tree stumps or other problem areas in your garden. As Frank Lloyd Wright said, "a physician may bury his mistakes ... but an architect can only plant a vine."
You can see a beautiful 'Sweet Autumn' clematis in full bloom in the Helen Latch Jones Rose Garden at Reiman Gardens.
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