Plants
Spirea planting zones
Spirea covers 3a–8b, but the zone is only half the answer. Of the 4 types below, 3 carry their flower display through the spring freeze window and 1 does not. That difference decides whether a late freeze costs you a season of flowers.
Published October 30, 2026 · Cite this page
The types
Which spirea you are choosing between
| Type | Zones | A late freeze |
|---|---|---|
| Vanhoutte spirea Spiraea × vanhouttei | 3a to 8b, then too little winter to flower | Exposed The classic arching white spring spirea, 5 to 8 feet tall (Clemson); often sold as bridal wreath. |
| Bridal wreath spirea Spiraea prunifolia | 5a to 8b, then too little winter to flower | Exposed Double white flowers before the leaves, about 6 feet; often found at old home sites (Clemson). |
| Thunberg spirea Spiraea thunbergii | 4a to 8b, then too little winter to flower | Exposed Also called baby’s breath spirea; among the earliest to bloom, 3 to 5 feet (Clemson). |
| Japanese and bumalda spirea Spiraea japonica and S. × bumalda (e.g. ‘Anthony Waterer’, ‘Goldflame’) | 4a to 8b, then too hot | Safe Pink summer flowers on new growth. Clemson and NC State call Japanese spirea invasive in the Southeast. |
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 spireas 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 |
|---|---|---|---|---|
| 3a | 1 of 4 | 1 | only 10 stations — too few to publish a range | |
| 3b | 1 of 4 | 1 | May 12 – May 30 across 92 stations | about 14 days later |
| 4a | 3 of 4 | 2 | May 6 – May 27 across 298 stations | about 14 days later |
| 4b | 3 of 4 | 2 | May 2 – June 1 across 477 stations | about 14 days later |
| 5a | 4 of 4 | 3 | April 28 – May 31 across 718 stations | about 14 days later |
| 5b | 4 of 4 | 3 | April 22 – May 28 across 752 stations | about 15 days later |
| 6a | 4 of 4 | 3 | April 18 – May 24 across 1004 stations | about 16 days later |
| 6b | 4 of 4 | 3 | April 11 – May 19 across 991 stations | about 16 days later |
| 7a | 4 of 4 | 3 | April 5 – May 9 across 941 stations | about 17 days later |
| 7b | 4 of 4 | 3 | March 30 – April 26 across 679 stations | about 16 days later |
| 8a | 4 of 4 | 3 | March 20 – April 16 across 689 stations | about 17 days later |
| 8b | 4 of 4 | 3 | March 7 – April 17 across 700 stations | about 19 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 11 zones above that publish a range, the median last spring freeze varies by 33 days inside a single zone — 18 days even in the tightest, zone 3b, and 41 in the widest, zone 8b. Two gardens with the same zone on the label can be a month apart on the date that decides whether spireas flower.
And the median is not the risk. Across the 5,741 NOAA stations serving these zones, the freeze that arrives one year in ten lands a median of 16 days after the median date, and 20 days after it at the tenth of stations where that tail runs longest. A variety marked exposed above has its flowers standing in front of that whole window, not in front of one date.
⛔ 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.
Spring spireas and summer spireas
Clemson calls spireas among the easiest flowering shrubs to grow, and splits them into spring bloomers and summer bloomers. The split decides everything else: spring spireas flower on last year’s wood, summer spireas on new growth (Penn State).
| Spirea | Blooms | Zones (Clemson) | Prune |
|---|---|---|---|
| Thunberg or baby’s breath spirea (Spiraea thunbergii) | Early spring, among the first | 4 to 8 | Soon after flowering |
| Bridal wreath spirea (S. prunifolia) | Spring, double white, before the leaves | 5 to 8 | Soon after flowering |
| Vanhoutte spirea (S. × vanhouttei) | Spring, masses of white | 3 to 8 | After flowering (NC State) |
| Reeves spirea (S. cantoniensis) | Spring, white | 5 to 8 | After flowering |
| Japanese and bumalda spirea (S. japonica, S. × bumalda) | Summer, pink, on new growth | 4 to 8 | Winter or early spring |
Penn State gives the same split: spring-blooming spirea (S. prunifolia and S. × vanhouttei) after flowering, summer-blooming spirea (S. × bumalda and S. japonica) in late winter or early spring. The late-freeze table above matters for the spring types only.
Japanese spirea is invasive in the Southeast
Clemson says Japanese spirea and its cultivars, including the bumalda spireas, are considered invasive in the Southeast and are not recommended there. NC State’s plant toolbox lists it as invasive in Virginia, Georgia, South Carolina, Tennessee and Kentucky and in the Great Smoky Mountains, says it self-seeds and spreads into dense thickets, and suggests native alternatives.
Planting
- Full sun for the densest growth and most flowers; spireas tolerate part shade (Clemson, NC State).
- Almost any soil except an extremely wet one (Clemson). NC State says Vanhoutte spirea does well in a wide range of soils, including clay, and tolerates some drought.
- Fall is the best time to plant, Clemson says, and late fall after leaf drop the best time to move one.
- Mulch and summer watering help (Clemson).
Test the soil if you are unsure of its pH; NC State’s toolbox lists Japanese spiraea for alkaline soils.
Pruning by type
- Spring spireas: after flowering, Clemson thins old and weak canes to the ground every year.
- Summer (bumalda) spireas: in winter or early spring; Clemson says they need less severe pruning than other spireas. Minnesota cuts late-blooming spireas back to the first pair of buds above the ground.
- Any spirea: Clemson removes faded flowers to stimulate a second flush of growth and more flowers.
- An overgrown spirea responds well to rejuvenation, cutting all the stems to the ground in early spring (Penn State).
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 removes faded spirea flowers to bring on a second flush of growth and more flowers.
- LoppersAfter a spring spirea flowers, Clemson thins old and weak canes to the ground every year.
Common problems
- Phytophthora and Pythium root rots in poorly drained, wet soils (Clemson).
- Leaf spots on bumalda cultivars, uncommon; Clemson says drip irrigation and raking up fallen leaves in late winter help.
- Aphids in spring (Clemson, NC State); Clemson uses insecticidal soap, sprayed in the early evening. Follow the label and your state’s rules.
- Like other rose-family plants, NC State says, spireas can get leaf spot, fire blight, powdery mildew, root rot, leaf roller and scale.
Clemson says spireas are generally deer resistant; NC State says Japanese spiraea may be damaged by deer.
Common mistakes
- Pruning a spring spirea before it flowers, which removes the buds on old wood (Penn State, NC State).
- Planting Japanese spirea in the Southeast, where Clemson and NC State call it invasive.
- Extremely wet soil (Clemson).
- Shade, which means fewer flowers (Clemson).
- Skipping the deadheading; Clemson says it brings a second flush of flowers.
We found no Texas A&M or UF/IFAS source on spireas we could read; the Southern advice here is Clemson’s and NC State’s.
Your ZIP code
Your ZIP, your answer
Enter your ZIP code to see your USDA zone, which of the 4 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 spirea?
- It depends on the type. Clemson prunes spring-blooming spireas after they flower and summer-blooming bumalda spireas in winter or early spring; Penn State Extension gives the same split.
- What zones do spireas grow in?
- Clemson rates Vanhoutte spirea for zones 3 to 8, Thunberg spirea 4 to 8, bridal wreath 5 to 8 and the bumalda spireas 4 to 8.
- Is Japanese spirea invasive?
- In the Southeast, yes. Clemson says it is considered invasive there and not recommended, and NC State Extension lists it as invasive in Virginia, Georgia, South Carolina, Tennessee and Kentucky.
- Should I deadhead spirea?
- Yes. Clemson says removing faded flowers on any spirea stimulates a second flush of growth and more flowers.
- What is the difference between Vanhoutte and bridal wreath spirea?
- Bridal wreath spirea (Spiraea prunifolia) has double flowers before the leaves; Vanhoutte spirea is a larger hybrid with masses of single white flowers, and Clemson says it is often sold as bridal wreath.
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, Spirea (HGIC 1074) (Revised September 15, 2015). Written for: South Carolina (USDA zones 8a–9b).
- NC State Extension Gardener Plant Toolbox, Spiraea × vanhouttei (Vanhoutte spiraea) . Written for: North Carolina (USDA zones 6b–9a).
- NC State Extension Gardener Plant Toolbox, Spiraea japonica (Japanese spiraea) . Written for: North Carolina (USDA zones 6b–9a).
- Penn State Extension, Pruning Flowering Shrubs , by Sandy Feather (Updated July 10, 2025). Written for: Pennsylvania (USDA zones 5b–8a).
- University of Minnesota Extension, Pruning trees and shrubs (Reviewed 2026). Written for: Minnesota (USDA zones 3a–5a).
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