Illustration
Sweet Autumn Clematis
Clematis terniflora
Sweet Autumn Clematis blooms from August through October.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Sweet Autumn Clematis
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 4–9. Expect it to reach about 13 ft tall and 5 ft wide at maturity, in roughly 3 years (not yet checked).
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Sweet Autumn Clematis
Plant Sweet Autumn Clematis in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 6, the middle of its hardy zones 4 to 9, spring means March to May and fall means August or September. Once settled, it blooms from August to October.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Sweet Autumn Clematis get?
13 fttall5 ft 7 inan adult5 ftwideSee Sweet Autumn Clematis in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Sweet Autumn Clematis
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Sweet Autumn Clematis about 5 ft apart, center to center, so each plant has room to reach its full width.
Add Sweet Autumn Clematis to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Sweet Autumn Clematis' height, spread, hardiness zones, sun and trait tags were checked against 13 published sources on July 30, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- Fine Gardeningplant guideheight, spread, hardiness zones, sun, years to mature size and trait tags
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun, years to mature size and trait tags
- fast-growing-trees.comFast Growing Treesheight, hardiness zones, sun, years to mature size and trait tags
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun and trait tags
- Plant Addictsheight, spread, hardiness zones, sun and trait tags
- The Morton Arboretumheight, hardiness zones, sun, years to mature size and trait tags
- Clemson Home and Garden Information CenterClemson Cooperative Extension Home and Garden Information Centerheight, sun, years to mature size and trait tags
- Holland Bulb Farmsheight, hardiness zones, sun and trait tags
- Oregon State UniversityLandscape Plantsheight, hardiness zones, sun and trait tags
- University of Illinois ExtensionHort Answersheight, hardiness zones, sun and trait tags
- extension.colostate.eduColorado State University Extensionsun, years to mature size and trait tags
- dendro.cnre.vt.eduVirginia Tech Dendrologyheight and trait tags
- Native Plant Trust (Go Botany)Native Plant Trust Go Botanyheight
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Sweet Autumn Clematis
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
In the buttercup family; the sap's protoanemonin irritates and can blister skin, and it sickens dogs, cats and horses. NC State rates its poison severity high. per NC State and ASPCA
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.