When should I prune Endless Summer hydrangeas?

Lightly, and never in late summer or fall, UNH Extension says. Clemson prunes right after the first flush of flowers. Iowa State and UNH wait until the plant leafs out in spring and remove only dead wood. Minnesota says the series flowers whether you prune it or not.

Do Endless Summer hydrangeas bloom on new wood?

On both. Minnesota, Penn State and Clemson say the series flowers on last year’s wood and on new wood. Iowa State says that after a mild winter they flower in early summer on old wood and in late summer on new growth.

Why is my Endless Summer hydrangea not blooming until late summer?

Usually winter. Iowa State says that after a cold winter Endless Summer, Blushing Bride and BloomStruck die back to ground level and flower only in late summer, on the current year’s growth. UNH says harsh winters often kill the flower buds in New Hampshire.

Should I deadhead Endless Summer hydrangeas?

Cornell Cooperative Extension in Orange County, New York, says cultivars such as Endless Summer and Blushing Bride bloom again on the current year’s growth if you remove faded blooms regularly. Oregon State says deadhead with care not to remove developing buds.

Guides

How to Prune Endless Summer Hydrangeas (Rebloomers)

Endless Summer hydrangeas flower on last year’s stems and on this year’s, so they bloom whether you prune or not. That makes pruning mostly a matter of what not to do: cut nothing in fall, take out dead wood once leaves show, and shape lightly right after the first flowers.

Published October 31, 2026 · Cite this page

Old wood and new wood

Endless Summer is a series of bigleaf hydrangeas, Hydrangea macrophylla. Penn State Extension says the first plant was found in 1998 flowering on old and new wood, and the series was introduced in 2004 after breeding work by Bailey Nurseries and Michael Dirr of the University of Georgia. Minnesota lists the original, ‘Bailmer’, with Blushing Bride, BloomStruck, Summer Crush and Twist ‘n’ Shout, and says they bloom on last year’s wood and on new wood, so they will bloom whether you prune them or not.

Iowa State Extension explains what that means in a year. After a mild winter these cultivars flower in early summer on the previous year’s growth and again in late summer on the current year’s. After a cold winter they die back to ground level and flower only in late summer, on new growth. Clemson says the first flush usually comes on old wood, then flower buds form on new wood and the plant repeats through summer.

An ordinary bigleaf hydrangea flowers on old wood only, and Minnesota prunes it after flowering and before August. The pruning guide by type covers it.

When to prune Endless Summer, by zone

Each zone’s median last spring freeze, the cold-year date NOAA says is passed in 9 years out of 10, and the median first fall freeze, from the median station. Beside them, what the extension services in states with ZIP codes in that zone say about pruning reblooming bigleaf hydrangeas.

Zone	Last spring freeze, median	Last spring freeze, cold year	First fall freeze, median	What sources for states in this zone say
Zone 3	May 19	June 1	September 22	University of Minnesota (Minnesota): the Endless Summer series flowers on old and new wood, so it blooms whether you prune it or not
Zone 4	May 13	May 27	September 28	University of Minnesota (Minnesota): the Endless Summer series flowers on old and new wood, so it blooms whether you prune it or not Iowa State University (Iowa): wait until the shrub begins to leaf out, then prune out all dead wood University of New Hampshire (New Hampshire): never prune in late summer or fall; in mid to late spring remove only dead canes
Zone 5	May 6	May 20	October 5	University of Minnesota (Minnesota): the Endless Summer series flowers on old and new wood, so it blooms whether you prune it or not Iowa State University (Iowa): wait until the shrub begins to leaf out, then prune out all dead wood University of New Hampshire (New Hampshire): never prune in late summer or fall; in mid to late spring remove only dead canes
Zone 6	April 28	May 13	October 17	Iowa State University (Iowa): wait until the shrub begins to leaf out, then prune out all dead wood University of New Hampshire (New Hampshire): never prune in late summer or fall; in mid to late spring remove only dead canes Ohio State University (Ohio): still give winter protection, and protect from April freezes Cornell (Orange County, New York): right after bloom, in summer; winter-damaged stems in late spring, after leaf-out NC State Gardener Plant Toolbox (North Carolina): do any pruning of bigleaf hydrangea before August 1
Zone 7	April 14	April 30	October 26	Ohio State University (Ohio): still give winter protection, and protect from April freezes Cornell (Orange County, New York): right after bloom, in summer; winter-damaged stems in late spring, after leaf-out NC State Gardener Plant Toolbox (North Carolina): do any pruning of bigleaf hydrangea before August 1
Zone 8	March 26	April 13	November 9	Clemson (South Carolina): any necessary pruning immediately after the first flush of flowers NC State Gardener Plant Toolbox (North Carolina): do any pruning of bigleaf hydrangea before August 1
Zone 9	February 25	March 21	December 1	Clemson (South Carolina): any necessary pruning immediately after the first flush of flowers NC State Gardener Plant Toolbox (North Carolina): do any pruning of bigleaf hydrangea before August 1
Zone 10	January 18	February 18	January 1	No source we read is written for a state in this zone

⚠️ A state spans several zones, and a zone spans many states. A rule shows in every zone its state has ZIP codes in, so read it with the state it was written for. The freeze dates are from the median NOAA station in each zone. None of these sources sets a pruning date by a freeze date: they time it by what the plant is doing, and the freeze dates show how far apart spring comes from one zone to the next.

The cold-year last freeze matters more here than on a panicle or smooth hydrangea: the first flush comes from buds that spent the winter on the stems, and Ohio State says to protect these plants from April freezes or the stressed plant will delay or reduce flowering.

What to do, season by season

When	What	Source
Late summer and fall	Do not prune. Last year’s growth carries next season’s buds.	UNH
Winter	Protect the buds where winters are hard; keep rabbits off the stems.	Ohio State; UNH; Minnesota
Spring, once leaves show	Prune out all dead wood, and only dead wood.	Iowa State; UNH
After the first flush	Any shaping that is needed.	Clemson; Cornell, Orange County
Through summer	Remove faded flowers for more on new growth.	Cornell, Orange County

NC State’s plant toolbox, writing for bigleaf hydrangea generally, says do any pruning before August 1, and Minnesota says bigleaf hydrangeas form next year’s buds in August and September.

Pruning in spring: dead wood only

Wait for leaves. Iowa State says for maximum bloom wait until the shrubs begin to leaf out before pruning. UNH says wait until mid to late spring, when you can see the winter damage.
See what winter killed. Iowa State says when growth appears, prune out all dead wood. Cornell Cooperative Extension in Orange County, writing about unprotected bigleaf hydrangeas, says delay any pruning until the buds swell to find the dead wood, then cut back to below the point of injury.
Remove the dead canes. UNH says only dead canes. Leave the live old stems: they carry the first flush.
Shape later, not now. Clemson leaves any needed pruning until immediately after the first flowers, and says to remove no more than a third of the plant.

Why hard winters still cost flowers

UNH Extension says the series is touted as hardy to zone 4, but harsh New Hampshire winters often kill its flower buds, and that the original Endless Summer will often bloom on new growth, but not consistently. After a severe winter, it says, expect a handful of flowers at most. Ohio State says winter protection is still recommended and the plants still need protecting from April freezes.

UNH suggests wrapping the plant with burlap or chicken wire and filling the enclosure with leaves, left on until all danger of frost has passed, and says that even this does not always work. If it still does not flower, UNH suggests moving it to a more protected spot, or trying BloomStruck or Twist-n-Shout, which it says bloom on new wood more readily. The how and when of covering is in hydrangea winter care.

Deadheading for the second flush

Cornell Cooperative Extension in Orange County, New York, says newer cultivars such as Endless Summer, Blushing Bride, ‘Red Sensation’ and ‘Double Pink’ will bloom again on the current year’s growth if faded blooms are removed regularly. Oregon State says deadhead spent flowers as you like, taking care not to remove developing buds. Oregon State also names other rebloomers: ‘Starlight’ (Let’s Dance), ‘Revolution’ (Everlasting) and ‘Fire Island’ (Seaside Serenade).

Color works as on any bigleaf hydrangea; Minnesota says Endless Summer’s pink to blue is achievable with proper soil amendment. See how to change hydrangea color.

Supplies

Supplies the sources mention

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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 prunersIowa State and UNH take out dead wood in spring once leaves show, and Minnesota makes heading cuts about 1/4 inch above a bud.
BurlapUNH says wrapping the plant with burlap or chicken wire and filling the enclosure with leaves can sometimes protect the buds.

Your ZIP code

Your ZIP, your answer

Enter your ZIP code to see your USDA zone, each zone’s freeze dates and what the sources there say about pruning reblooming hydrangeas, read from the table on this page, and the freeze dates of the NOAA station nearest you.

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Full details for any ZIP code: ZIP code zone finder.

Common mistakes

Cutting it back in fall. UNH says never prune bigleaf hydrangeas in late summer or fall.
Pruning before leaves show. Live and dead stems look alike until then (Iowa State; UNH).
Cutting it to the ground because it reblooms. The first flush comes from old wood (Clemson; Iowa State).
Uncovering too early. Ohio State says forgetting late spring frosts makes winter protection futile.
Feeding to force flowers. Oregon State says most hydrangeas bloom better if a little starved.

In the South

Clemson, writing for South Carolina, prunes the Endless Summer series right after the first flush, and NC State says to prune bigleaf hydrangeas before August 1; it rates bigleaf hydrangea from zone 6a to 11b. We found no Texas A&M or LSU source on reblooming hydrangeas, so advice for Texas and Louisiana here is limited; ask your county extension office.

Every pruning guide

Questions

When should I prune Endless Summer hydrangeas?: Lightly, and never in late summer or fall, UNH Extension says. Clemson prunes right after the first flush of flowers. Iowa State and UNH wait until the plant leafs out in spring and remove only dead wood. Minnesota says the series flowers whether you prune it or not.
Do Endless Summer hydrangeas bloom on new wood?: On both. Minnesota, Penn State and Clemson say the series flowers on last year’s wood and on new wood. Iowa State says that after a mild winter they flower in early summer on old wood and in late summer on new growth.
Why is my Endless Summer hydrangea not blooming until late summer?: Usually winter. Iowa State says that after a cold winter Endless Summer, Blushing Bride and BloomStruck die back to ground level and flower only in late summer, on the current year’s growth. UNH says harsh winters often kill the flower buds in New Hampshire.
Should I deadhead Endless Summer hydrangeas?: Cornell Cooperative Extension in Orange County, New York, says cultivars such as Endless Summer and Blushing Bride bloom again on the current year’s growth if you remove faded blooms regularly. Oregon State says deadhead with care not to remove developing buds.

Sources

Dates on this page are computed when the site is built from NOAA's 1991–2020 Climate Normals (first fall freeze at 32 °F, for every station the ZIP codes in each zone cite). Zones are the USDA Plant Hardiness Zone Map, 2023. Every rule — how long before or after a freeze to plant, how deep, how much — is quoted from the extension publications below, each of which writes for its own area.

University of Minnesota Extension, Pruning hydrangeas for best bloom . Written for: Minnesota (USDA zones 3a–5a).
Penn State Extension, When to Prune Which Hydrangea Species , by Sandy Feather (Updated December 16, 2025). Written for: Pennsylvania (USDA zones 5b–8a).
Iowa State University Extension and Outreach, Pruning Hydrangeas , by Richard Jauron and Aaron Steil (Last reviewed June 2022). Written for: Iowa (USDA zones 4b–6a).
University of New Hampshire Extension, How do I protect my ENDLESS SUMMER Hydrangea over the winter? , by Ask UNH Extension Infoline (December 14, 2017). Written for: New Hampshire (USDA zones 4a–6b).
Ohio State University Extension, Selecting Hydrangeas for the Home Landscape (HYG-1263) , by Eric Barrett (July 20, 2018). Written for: Ohio (USDA zones 6a–7a).
Clemson Cooperative Extension, Home & Garden Information Center, Pruning Hydrangeas , by Andrew “Drew” Jeffers (March 5, 2020). Written for: South Carolina (USDA zones 8a–9b).
Cornell Cooperative Extension, Orange County, Hydrangeas: Types and How to Prune . Written for: Orange County, New York (USDA zones 6b–7a).
NC State Extension Gardener Plant Toolbox, Hydrangea macrophylla (bigleaf hydrangea) . Written for: North Carolina (USDA zones 6b–9a).
Oregon State University Extension Service, General care for hydrangeas (Published June 2018, reviewed 2024). Written for: Oregon (USDA zones 5b–9b).
Oregon State University Extension Service, Hydrangeas bring beauty and variety to Oregon gardens , by Kym Pokorny (Published June 2024, reviewed 2025). Written for: Oregon (USDA zones 5b–9b).

Nothing here replaces your own state's cooperative extension service, which knows your county. Where this site's numbers come from.

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