Plants · Flowers
Clematis planting zones
Clematis (Clematis species and hybrids) is a perennial. By the type table below, at least one type lives through winter in the ground in 4a–9b; outside those zones, none of the types on this page is rated. Below the types are the dates its year turns on: each zone’s median last spring freeze and first fall freeze, from NOAA records.
Published October 24, 2026 · Updated October 30, 2026 · Cite this page
The types
Which clematis to grow
| Type | Hardy in the ground | Notes |
|---|---|---|
| Late, new-wood clematis (group 3) Clematis × jackmanii, C. viticella and their hybrids (e.g. ‘Jackmanii’, ‘Polish Spirit’) | 4a to 9a, then too hot or humid | Bloom on the current season’s growth. Iowa State calls them the most reliable in Iowa; Clemson says Italian clematis is adapted to a hot climate. |
| Large-flowered hybrids (group 2) Clematis hybrids (e.g. ‘Nelly Moser’, ‘Henryi’, ‘The President’) | 4b to 8b, then too hot or humid | Bloom on last year’s wood and again on new growth. Iowa State: if last year’s growth dies back, they may bloom only once. |
| Early, old-wood clematis (group 1) Clematis alpina, C. macropetala | 4a to 7b, then too hot or humid | Bloom in spring on the previous year’s stems. Clemson says downy clematis prefers cooler, shady places and grows best in the Upper Piedmont. |
| Anemone clematis (group 1) Clematis montana | 6a to 8b, then too hot or humid | Vigorous, 20 to 30 feet, white or pink flowers in May and June (Clemson). |
| Texas clematis (group 3) Clematis texensis (e.g. ‘Duchess of Albany’) | 5a to 9b, then too hot or humid | A Texas native that Clemson says stands up to hot, dry summers. Texas A&M’s Smith County list names it among native clematis. |
| Evergreen clematis (group 1) Clematis armandii | 7b to 9b, then too hot or humid | Flowers in late March in South Carolina (Clemson). Oregon State says it is sensitive to cold. |
Zone ranges are a judgement: horticultural convention set beside what the sources below say, not a measurement. In the next table the freeze dates are measured, and the count of hardy types comes from these judged ranges.
Zone by zone
Where clematis lives through winter, and when the freezes fall
Each date is the median across every NOAA station the zone’s ZIP codes cite, 1991–2020 normals. The middle half of those stations falls within the range shown beside it.
| Zone | Types hardy in the ground | Last spring freeze | First fall freeze |
|---|---|---|---|
| 3a | 0 of 6 | only 10 stations with comparable freeze dates — too few to publish a date | |
| 3b | 0 of 6 | May 18 · middle half May 15 – May 25 | September 23 · middle half September 17 – September 26 |
| 4a | 2 of 6 | May 15 · middle half May 10 – May 21 | September 27 · middle half September 22 – September 30 |
| 4b | 3 of 6 | May 11 · middle half May 5 – May 23 | September 30 · middle half September 23 – October 3 |
| 5a | 4 of 6 | May 9 · middle half May 1 – May 20 | October 2 · middle half September 26 – October 7 |
| 5b | 4 of 6 | May 4 · middle half April 27 – May 15 | October 8 · middle half October 1 – October 14 |
| 6a | 5 of 6 | May 1 · middle half April 24 – May 9 | October 14 · middle half October 5 – October 20 |
| 6b | 5 of 6 | April 25 · middle half April 17 – May 3 | October 20 · middle half October 11 – October 24 |
| 7a | 5 of 6 | April 19 · middle half April 11 – April 27 | October 23 · middle half October 17 – October 28 |
| 7b | 6 of 6 | April 8 · middle half April 3 – April 16 | October 30 · middle half October 25 – November 3 |
| 8a | 5 of 6 | March 30 · middle half March 25 – April 5 | November 5 · middle half November 1 – November 10 |
| 8b | 5 of 6 | March 20 · middle half March 13 – March 29 | November 12 · middle half November 7 – November 18 |
| 9a | 3 of 6 | March 5 · middle half February 24 – March 15 | November 24 · middle half November 18 – December 2 |
| 9b | 2 of 6 | February 12 · middle half January 30 – February 25 | December 8 · middle half December 1 – December 17 |
| 10a | 0 of 6 | 107 of 190 stations here record no ordinary freeze, so there is no freeze date to count from | |
| 10b | 0 of 6 | 70 of 79 stations here record no ordinary freeze, so there is no freeze date to count from | |
| 11a | 0 of 6 | 34 of 34 stations here record no ordinary freeze, so there is no freeze date to count from | |
| 11b | 0 of 6 | 12 of 12 stations here record no ordinary freeze, so there is no freeze date to count from | |
“Types hardy in the ground” is a judgement, from the type table above. The freeze dates are measured.
A zone does not tell you your own dates. Inside a single zone the median last spring freeze still varies by 34 days from station to station, so the box below gives the dates of the NOAA station nearest your ZIP code.
Your ZIP code
Your ZIP, your answer
Enter your ZIP code to see your USDA zone, how many of the 6 types on this page live through that zone’s winter and when its freezes fall, read from the table on this page, and the freeze dates of the NOAA station nearest you.
Your answer appears here.
Full details for any ZIP code: ZIP code zone finder.
Which clematis for your zone, and its pruning group
Clematis are sorted into three groups by when and on what wood they bloom, and the group decides both how reliable a clematis is in a cold winter and how to prune it. Iowa State University Extension and Outreach says group 1 blooms earliest, usually in May, on the previous season’s stems, and is often the hardest to grow in Iowa because winter dieback can destroy the flower buds. Group 2 blooms twice, first on last season’s growth and again in late summer on new growth, and may bloom only once if last year’s growth dies back. Group 3 flowers on the current year’s growth, and Iowa State calls it the most reliable performer in Iowa.
Clemson’s Home & Garden Information Center says there are clematis suitable for all areas of South Carolina. It calls Italian clematis (C. viticella) tolerant of warm roots and adapted to a hot climate, says Texas clematis (C. texensis) stands up to hot, dry summers, and says downy clematis (C. macropetala) prefers cooler, shady places and grows best in the Upper Piedmont. Oregon State University Extension says evergreen Clematis armandii is sensitive to cold and best in western Oregon’s valleys and on the coast, and that central and eastern Oregon need very cold-hardy deciduous clematis.
Clemson does not recommend sweet autumn clematis (C. terniflora): it is highly invasive, grows to 30 feet, reseeds freely, and is on South Carolina’s invasive species list.
Planting
Clemson says clematis like their heads in the sun and their feet in the shade: at least 6 hours of sun to flower best, afternoon shade in South Carolina, and the roots kept cool by low plants or a 2-inch mulch. Texas A&M AgriLife’s Smith County list says the same for northeast Texas: roots cool and in shade, top in sun. Iowa State says early spring is the best time to plant, though container plants can go in all season.
All the sources plant the crown below the soil, and they disagree on how far. Iowa State sets it an inch below the surface, to encourage several shoots and protect it in winter. Clemson plants it one to two inches below, so the plant can recover if it is mowed off, chewed or struck by clematis wilt. Oregon State sets it 2–3 inches below. University of Illinois Extension sets the plant so the first two sets of leaf nodes are underground.
Clemson prepares the soil 18 inches deep and 12 to 15 inches wide, and cuts the stems back to 12 inches at planting. Iowa State trims to 12 inches or a pair of low buds after planting, and Illinois prunes newly planted clematis to 12 inches the following spring, for a fuller plant. Iowa State sets the plant about 1-2 feet from its support.
Water, feeding and support
Iowa State and Clemson say clematis need at least an inch of water a week and cool roots, so mulch matters. Clemson says not to fertilize while the vine is flowering; Iowa State feeds established plants in spring with a low-analysis fertilizer such as 10-10-10 or 5-10-5. Illinois’s Knox County Master Gardeners fertilize after the first bloom for groups 1 and 2, and after spring pruning for group 3.
Clematis climb by twisting their leaf stalks around a support, Iowa State says, so Clemson says supports must be thin: a clematis cannot grasp thick branches or heavy trellising.
Supplies
Supplies the sources mention
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- Thin trellis or plant supportClemson says clematis supports must be thin: a clematis cannot grasp thick branches or heavy trellising.
- Bypass hand prunersClemson cuts the large-flowered hybrids back to the topmost pair of large, plump green buds in February or March.
Pruning by group
Clemson’s rules: group 1 (early-flowering, such as C. alpina, C. macropetala, C. armandii and C. montana) is pruned as soon as possible after bloom, but no later than the end of July. Group 2 (the large-flowered hybrids such as ‘Nelly Moser’) is pruned lightly in February or March, removing dead and weak stems and cutting the rest back to the topmost pair of large, plump green buds. Group 3 (late-flowering, such as C. viticella and ‘Jackmanii’) is cut back in February or March, each stem to about 2 to 3 feet.
The sources disagree on how low to cut group 3. Illinois cuts it back to 8-12 inches in spring, Illinois’s Knox County Master Gardeners prune just above the lowest living bud, usually 6-18 inches, and Iowa State to within 6 to 12 inches of the ground in late winter or early spring. NC State Extension says group 3 can be cut nearly to the ground in late winter.
If you do not know the group, Iowa State says to watch the plant for a year: a clematis that blooms first in May is likely group 1, one that blooms twice is group 2, and one that blooms only later is group 3, or a group 2 hurt by winter. Illinois says to keep the plant label. Iowa State adds that pruning is not essential; an unpruned clematis still blooms.
Full guide: How to Prune Flowering Shrubs: Spring vs Summer Bloomers
Getting clematis through winter
Iowa State says not all clematis are reliably hardy in Iowa. If a group 1 clematis dies back in winter, prune to live wood after bud break in spring; if a group 2 suffers extensive dieback, cut the vines back to two feet in early spring, at the cost of the spring flowers. Oregon State uses deep mulch and protected spots, away from winter wind, in cold central and eastern Oregon. Planting the crown below the soil, Iowa State says, also gives it winter protection.
Why clematis does not bloom
- Low light. Iowa State says most clematis need at least 6 hours of direct sun a day to bloom well.
- Feeding. Iowa State says too little fertilizer can reduce bloom, and too much nitrogen gives growth but few flowers.
- Pruning at the wrong time. Iowa State says a hard cut at the wrong time removes the flower buds; Clemson and Illinois give the timing for each group.
- Winter damage. Iowa State says groups 1 and 2 lose flowers when last year’s growth dies back.
- Too young. Iowa State says a clematis can take up to three years to establish and bloom. Clemson quotes the old saying: the first year they sleep, the second year they creep, and the third year they leap.
Common problems
Clemson calls clematis wilt the most devastating problem: part or all of the vine suddenly collapses and blackens. Cut off and destroy the affected parts. Clemson says a clematis planted with two buds below the ground usually grows back from the base the next year, and that wilt is mainly a disease of the large-flowered hybrids, so small-flowered species are a choice after trouble. Illinois’s Knox County Master Gardeners prune affected stems 1 to 2 inches below the infected part. Oregon State says sudden wilting may also come from a broken stem, voles or vine weevil grubs, or poor drainage.
Clemson also names powdery mildew where air circulation is poor, aphids and mites on new growth, and slugs on newly planted vines, and says to water at the base of the plant to keep the leaves dry.
NC State’s plant toolbox rates clematis high in poison severity: it says eating it can cause severe mouth pain and ulcers, that it is toxic to dogs, cats and horses, and that its sap can cause skin redness and burning in some people, so gardening gloves are recommended.
Common mistakes
- Pruning without knowing the group. Iowa State says improper pruning sacrifices blooms.
- Planting the crown at soil level. Every source we read plants it below the surface, from an inch (Iowa State) to 2–3 inches (Oregon State).
- Cooking the roots. Clemson keeps them cool and shaded with mulch or low plants.
- Giving up in year one. Clemson: the first year they sleep, the second year they creep.
- Planting sweet autumn clematis in the Southeast. Clemson says it is highly invasive.
We found no Florida, Louisiana or Alabama source for clematis that we could read, and the Texas source we read, Texas A&M AgriLife’s Smith County list, names clematis in one line without growing advice. The Southern growing advice on this page is Clemson’s and NC State’s.
Questions
- What are the three clematis pruning groups?
- Iowa State and Clemson describe them: group 1 blooms in spring on last year’s stems, group 2 blooms on last year’s stems and again on new growth, and group 3 blooms on the current year’s growth. Clemson prunes group 1 after bloom, group 2 lightly in February or March, and group 3 back to about 2 to 3 feet in February or March.
- How deep should I plant a clematis?
- The sources disagree. Iowa State sets the crown an inch below the soil, Clemson one to two inches, Oregon State 2–3 inches, and Illinois buries the first two sets of leaf nodes. All plant below the surface.
- Why did my clematis suddenly wilt?
- Clemson says clematis wilt, a fungal disease mainly of large-flowered hybrids, collapses and blackens stems, and a plant set with two buds below ground usually regrows. Oregon State says a broken stem, voles, vine weevil grubs or poor drainage can look the same.
- Is clematis poisonous to pets?
- NC State’s plant toolbox rates clematis high in poison severity, says it is toxic to dogs, cats and horses, and that its sap can irritate skin, so it recommends gardening gloves.
- Which clematis grows best in a hot climate?
- Clemson says Italian clematis (C. viticella) is adapted to a hot climate and Texas clematis (C. texensis) stands up to hot, dry summers, and that the large-flowered hybrids benefit from afternoon shade in South Carolina.
Sources
Freeze dates on this page are NOAA 1991–2020 Climate Normals, for every station the ZIP codes in each zone cite. Zones are the USDA Plant Hardiness Zone Map, 2023. The type table is a judgement, as labelled above. Growing advice is quoted from the extension publications below, each written for its own area.
- Clemson Cooperative Extension, Home & Garden Information Center, Clematis (HGIC 1104) (Updated August 31, 2024). Written for: South Carolina (USDA zones 8a–9b).
- Iowa State University Extension and Outreach, Growing Clematis in Iowa (Last reviewed June 2026). Written for: Iowa (USDA zones 4b–6a).
- University of Illinois Extension, Clematis . Written for: Illinois (USDA zones 5a–7a).
- University of Illinois Extension, Clematis: Queen of the Vines , by Knox County Master Gardeners (September 2018). Written for: Knox County, Illinois (USDA zone 5b).
- Oregon State University Extension Service, How to grow clematis for long-lasting color in Oregon gardens . Written for: Oregon (USDA zones 5b–9b).
- NC State Extension Gardener Plant Toolbox, Clematis . Written for: North Carolina (USDA zones 6b–9a).
- Texas A&M AgriLife Extension Service, Outstanding Landscape Plants for Northeast Texas , by Keith C. Hansen, Smith County Extension Horticulturist . Written for: Northeast Texas.
Published October 24, 2026 · Updated October 30, 2026
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