The Magic of Sweet Autumn Clematis

Written by: Ruth Sens, Weld County Master Gardener 

There is a plant that reigns over my Greeley garden this time of year and it is a clematis vine. More specifically, Sweet Autumn clematis vines (Clematis terniflora) faithfully provide wonderful masses of fragrant creamy white blooms the first week of September. This plant absolutely lights up my tired late-summer garden with much needed beauty and fragrance when most everything else has stopped blooming. 

Sweet Autumn clematis produces masses of fragrant white blooms in the early fall (photo by R. Sens).

The early and mid-summer blooming clematis vines with the larger blooms get serious adoration from gardeners. I do have them planted in my garden also but this clematis is my favorite. Reasons to love this vine include the attractive green leaves in summer, the stunning amount of beautiful blooms, the wonderful fragrance, and the fact that it is a fast growing vine.

The fragrant white blooms awaken the late-summer garden (photo by R. Sens).

You can plant it now but spring planting is optimal. Choose a spot where you will be able to see the mass of flowers and enjoy the fragrance in late summer. Although some sources suggest it will bloom well in part shade, Sweet Autumn blooms most prolifically for me when planted in full sun. This clematis likes a location where the roots can be kept cool in the shade of other shorter garden plants. Dig in some compost when planting, mulch, and then keep the soil moist but not water logged. Sweet Autumn clematis may take a few years to become fully established and winter watering is advised.

The fast growth (15-20 feet per year) means it requires a strong trellis and/or support that it can twine on. Feature it in your perennial garden on a strong accent trellis, on an arbor, a pergola, or even along the top of a chain-link fence. Gorgeous! The flowers will turn into fuzzy seed heads that I think look beautiful in the winter landscape.

Sweet Autumn clematis is a vigorous climber, so provide it with support or a structure (photo by R. Sens).

These vines bloom on new growth so can be pruned to produce optimal blooms. They thrive after a heavy pruning in spring, cut down to 12-18 inches when new green shoots start to emerge. This can be a physical workout if the plant has gotten large, but then you can stand back to watch in amazement as it grows and blooms again. Plants established in optimal conditions can live up to 20 years.

Of note, Sweet Autumn is considered invasive in several Eastern states. It is not listed on the Colorado Noxious Weed list. 

This should be an easy decision if you have the right spot and want a gorgeous large vine. Plant and enjoy! Refer to this University of Wisconsin Extension publication for more information.