Plants
Rose of Sharon planting zones
Rose of Sharon covers 5a–9b, but the zone is only half the answer. All 3 types below flower on the current season’s growth, after the spring freeze window closes, so the bigger questions here are winter hardiness and pruning.
Published October 30, 2026 · Cite this page
The types
Which rose of Sharon you are choosing between
| Type | Zones | A late freeze |
|---|---|---|
| Single-flowered rose of Sharon Hibiscus syriacus (e.g. ‘Diana’, ‘Helene’, ‘Aphrodite’, ‘Minerva’) | 5a to 9b, then too hot | Safe The U.S. National Arboretum introductions named here set few seeds (Clemson). |
| Semi-double rose of Sharon Hibiscus syriacus Chiffon series | 5a to 9b, then too hot | Safe Blue Chiffon and Lavender Chiffon (Clemson). |
| Double-flowered rose of Sharon Hibiscus syriacus (e.g. ‘Blushing Bride’, ‘Lucy’, Smoothie series) | 5a to 9b, then too hot | Safe Some doubles may still set a little seed; the Smoothie series is completely sterile (Clemson). |
Zone ranges and bloom habit are a judgement — horticultural convention, not a measurement, and the same standing as the heat ratings on our crop tables. Everything below this panel is measured.
Zone by zone
Which rose of Sharon shrubs are hardy where, and when the freeze lands
The two left columns come from the variety table above — a judgement. The two right columns are measured: they are the median last spring freeze across every NOAA station the zone’s ZIP codes actually cite, and how much later the one-year-in-ten freeze arrives.
| Zone | Hardy here | Flowers exposed | Last spring freeze | 1 year in 10 |
|---|---|---|---|---|
| 5a | 3 of 3 | none | April 28 – May 31 across 718 stations | about 14 days later |
| 5b | 3 of 3 | none | April 22 – May 28 across 752 stations | about 15 days later |
| 6a | 3 of 3 | none | April 18 – May 24 across 1004 stations | about 16 days later |
| 6b | 3 of 3 | none | April 11 – May 19 across 991 stations | about 16 days later |
| 7a | 3 of 3 | none | April 5 – May 9 across 941 stations | about 17 days later |
| 7b | 3 of 3 | none | March 30 – April 26 across 679 stations | about 16 days later |
| 8a | 3 of 3 | none | March 20 – April 16 across 689 stations | about 17 days later |
| 8b | 3 of 3 | none | March 7 – April 17 across 700 stations | about 19 days later |
| 9a | 3 of 3 | none | February 15 – April 6 across 446 stations | about 22 days later |
| 9b | 3 of 3 | none | February 2 – April 6 across 218 stations | about 27 days later |
“Hardy here” and “flowers exposed” are a judgement, from the variety table above. The freeze dates are measured — NOAA 1991–2020 climate normals, and the range is across the stations the zone’s own ZIP codes cite rather than one station chosen to speak for it.
Why the date matters
Your zone does not tell you your last freeze
Across the 10 zones above that publish a range, the median last spring freeze varies by 36 days inside a single zone — 27 days even in the tightest, zone 7b, and 63 in the widest, zone 9b. Two gardens with the same zone on the label can be a month apart on their last spring freeze.
And the median is not the risk. Across the 5,548 NOAA stations serving these zones, the freeze that arrives one year in ten lands a median of 16 days after the median date, and 22 days after it at the tenth of stations where that tail runs longest. None of the types above flowers inside that window, which is why this page puts winter hardiness and pruning first.
⛔ We publish no temperature at which a bud is lost. NOAA’s normals give dates, not damage thresholds, and inventing a number to bridge the two is the one thing this site refuses everywhere else. What is on this page is when the freeze arrives and which flowers are out when it does.
Which rose of Sharon for your zone
NC State Extension’s plant toolbox rates rose of Sharon, also called shrub althea, for zones 5a to 9b, and Mississippi State gives zones 5 to 9. It flowers on the current season’s growth in the heat of July, August and early September (Clemson), so a late spring freeze, which the table above dates for your zone, comes long before its flowers form.
| Kind | Examples | Seed (Clemson) |
|---|---|---|
| Single-flowered | ‘Diana’ (white), ‘Helene’ (white, red eye), ‘Aphrodite’ (deep pink), ‘Minerva’ (lavender) | Few seeds |
| Semi-double | Blue Chiffon, Lavender Chiffon | — |
| Double | ‘Blushing Bride’, ‘Lucy’ | May still set some seed |
| Double, sterile | Peppermint Smoothie, Blueberry Smoothie | Completely sterile |
Seedlings and invasiveness
Clemson says some rose of Sharon cultivars set highly fertile seed pods that become a nuisance, and recalls one rescued roadside shrub that produced countless offspring. NC State says rose of Sharon has been reported invasive in some states, including Virginia and Kentucky. The sterile and near-sterile cultivars above are Clemson’s answer.
Planting
- Full sun for the best flowers; it tolerates part shade (Clemson, NC State).
- Moist, well-drained soil, though NC State says it tolerates all but extremely wet or dry soils and is pH adaptable. Mississippi State says it adapts to many soil types and is drought tolerant once established.
- Room for 8 to 10 feet tall and 4 to 6 feet wide (Clemson); NC State gives 8 to 12 by 6 to 10. For a hedge, NC State plants 6 to 12 feet apart.
- It likes hot weather and tolerates salt, deer and wet soil moderately (NC State).
Pruning in late winter
Because the flowers come on the current season’s branches, Clemson prunes rose of Sharon any time in late winter, with bypass pruners or loppers. NC State says spring pruning encourages flowers on new growth and increases flower size, and University of Missouri Extension prunes summer-flowering shrubs like it any time before new growth begins in spring.
Full guide: How to Prune Flowering Shrubs: Spring vs Summer Bloomers
Supplies
Supplies the sources mention
Each link opens an Amazon search for a plain kind of product, not one we picked. We have not tested these, and we do not rank them.
As an Amazon Associate I earn from qualifying purchases. It costs you nothing extra and changes nothing on this page: the dates are NOAA’s and the advice is the extension services’. Affiliate disclosure
- Bypass hand prunersClemson prunes rose of Sharon in late winter, preferably with bypass pruners or loppers.
- LoppersClemson names loppers alongside bypass pruners for the late-winter pruning.
Late leaves are normal
Rose of Sharon is deciduous (NC State, Mississippi State) and blooms from midsummer into early fall. Its late flowers, Mississippi State says, give color when many other plants have finished.
Common problems
- Seedlings from fertile cultivars, the one problem Clemson and NC State both raise.
- Few pests or diseases otherwise; Mississippi State calls it low-maintenance and deer resistant.
- Leggy older cultivars; Clemson says the newer sterile ones were selected for a more compact form.
Common mistakes
- Planting a seedy cultivar, which Clemson says can become a nuisance.
- Pruning in late spring or summer; the flowers come on the current season’s branches (Clemson).
- Shade, which costs flowers (Clemson).
- Extremely wet or dry soil (NC State).
- Too little room: it reaches 8 to 12 feet (NC State).
We found no Texas A&M or UF/IFAS source on rose of Sharon we could read; the Southern advice here is Clemson’s, NC State’s and Mississippi State’s.
Your ZIP code
Your ZIP, your answer
Enter your ZIP code to see your USDA zone, which of the 3 types on this page are rated for that zone and when its late-freeze window runs, 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.
Questions
- When should I prune rose of Sharon?
- In late winter. Clemson says the flowers come on the current season’s branches, so prune any time in late winter; NC State Extension says spring pruning increases flower size.
- How do I stop rose of Sharon from spreading seedlings?
- Plant a sterile or near-sterile cultivar. Clemson names the Smoothie series as completely sterile and ‘Diana’, ‘Helene’, ‘Aphrodite’ and ‘Minerva’ as setting few seeds.
- What zones does rose of Sharon grow in?
- NC State Extension rates it for zones 5a to 9b, and Mississippi State Extension gives zones 5 to 9.
- When does rose of Sharon bloom?
- In July, August and early September, Clemson says, and Mississippi State says from midsummer to early fall.
- Is rose of Sharon invasive?
- NC State Extension says it has been reported invasive in some states, including Virginia and Kentucky, and Clemson says fertile cultivars can produce a nuisance of seedlings.
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.
- NC State Extension Gardener Plant Toolbox, Hibiscus syriacus (rose of Sharon) . Written for: North Carolina (USDA zones 6b–9a).
- Clemson Cooperative Extension, Home & Garden Information Center, Bring on the Heat—Bring on the Blooms with Rose-of-Sharon , by Robert F. Polomski (July 27, 2023). Written for: South Carolina (USDA zones 8a–9b).
- Mississippi State University Extension, Rose of Sharon hibiscus is pretty pass-along plant (Southern Gardening) (August 12, 2024). Written for: Mississippi (USDA zones 7b–9a).
- University of Missouri Extension, Pruning Ornamental Shrubs (G6870) , by Christopher J. Starbuck . Written for: Missouri (USDA zones 5b–8a).
- Clemson Cooperative Extension, Home & Garden Information Center, Pruning Shrubs (HGIC 1053) (Reviewed August 22, 2015). Written for: South Carolina (USDA zones 8a–9b).
Published October 30, 2026
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- All plant guides
- When to Plant Trees and Shrubs in Fall, by Zone — watering and mulch after planting, and the last fall planting date for each zone
- ZIP code zone finder — your exact USDA zone, and your nearest NOAA station’s freeze dates
- What survives my winter — the same zone arithmetic over 74 perennial edibles, which is a separate table from the one above
- When to start my seeds — the spring calendar anchored on the same measured last-freeze dates
- Your hardiness zone is not a planting date — the whole dataset behind the spread quoted above