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Everything You Need to Know About Endless Summer Hydrangeas

Author Icon By Brenda Woods Updated 03/05/2024

Endless Summer hydrangeas take the traditional hydrangea to the next level. They can grow their enormous, bold flowers on both old and new wood—making for an exceedingly long blooming season and the potential for reblooms. You can even customize your Endless Summer hydrangea, adjusting the soil pH to yield either vivid blue, pale lavender, soft mauve, or deep pink mophead blooms.

As a cold-hardy specimen, they can even tolerate frost—making them ideal for gardens beyond the South. Here’s everything you need to know about Endless Summer hydrangeas.


Endless Summer Hydrangeas at a Glance

Bloom on both old and new wood
Flowers can be pink, lavender or blue
Cold hardy
Blooming period spans from summer to fall
Can be grown in a container
Prefer partial shade in warmer climates

Appearance

The Endless Summer hydrangea is a shrub that grows in a rounded shape. Its dark green leaves range from 4–8 inches long, and its blooms are showy mopheads nearly 8–10 inches in diameter.

You can choose from a range of colors, depending on the alkalinity or acidity of your soil. Shades range from deep blue to light lavender, soft mauve to vivid pink. The more acidic the soil, the bluer the bloom, and the more alkaline the soil, the pinker.

Endless Summer Hydrangeas are compact, growing 3–4 feet tall with a 3–4 foot spread.


Specifications

Appearance

Rounded shape with dark green, serrate, obovate to elliptical leaves. Massive mophead flowers that can be either blue, pink, or in between

Height

3-4 feet tall

Hardiness Zones

Zones 4-8

Type of tree

Deciduous shrub

Sunlight requirements

Partial shade

Soil composition

Well-drained and moist. Can grow in range of alkaline to acidic soils


Hardiness Zones

USDA Hardiness Zones indicate the regions where plants can grow based on minimum winter temperatures. Endless Summer hydrangeas grow in Zones 4–8, making them able to thrive in more parts of the country than other hydrangea varieties. They are cold-hardy enough to withstand frost and can tolerate some heat. However, in warmer climates, they should receive minimal afternoon sun.


Planting

Fall or early spring are the best times to plant Endless Summer hydrangeas. You want to give them time to establish a healthy root system before the blooming season begins.

Choose a sheltered planting site that receives partial shade—ideally, sun in the mornings and shade in the afternoon.

Before planting, decide what color Endless Summer hydrangea blossoms you want. For bluer blossoms, you can amend your soil with sulfur. If you’re more interested in bold pinks, amend it with lime.

When you’re ready to plant, dig a hole twice the width of your Endless Summer root ball and roughly its depth. You want your plant to be just slightly higher than the level of the surrounding soil.

Begin to backfill the hole with soil. Stop halfway and pour water into the hole until it rises to the top. Once it drains away, finish filling in the rest of the soil.

If you’re planting your Endless Summer hydrangeas as foundation plants, space them 8 feet apart from each other, measuring from the center of each plant. For a garden border, space them out 4 feet apart.


Endless Summer hydrangeas actually enjoy partial shade to full sun and are able to bloom on both old and new growth from spring through summer or early summer to fall, depending on the climate you live in.

Sun and shade

Endless Summer hydrangeas thrive in partial shade, or roughly four hours of direct, unfiltered sunlight per day. It’s best if they receive sun in the morning and shade in the afternoon.

Soil

Endless Summer hydrangeas can grow in a range of soils but need moisture to flourish. The key thing to remember about soil is that the level of acidity or alkalinity will determine the color—from blue to purple to pink. For a bluer shade, make sure your soil is acidic. For pinker, amend it to more alkaline, as needed.

Watering

You should water your Endless Summer hydrangea routinely each week, up to twice a week during the hotter months.

Fertilizing

Fertilize your Endless Summer hydrangea once in spring or summer with a specially formulated fertilizer. Slow-release fertilizer is encouraged, but a fast-release balanced fertilizer with an NPK value of 10-10-10 will also work.

Pruning

You do not have to prune your Endless Summer hydrangea, because they can bloom on both old and new growth. But you should trim any dead, dying, or diseased branches when you notice them.


FAQ About Endless Summer Hydrangeas

Why are my Endless Summer hydrangeas not blooming?

Over-pruning is a common reason for why Endless Summer hydrangeas are not blooming. They bloom on both old and new growth, so they do not require pruning unless there are dead, dying, or diseased branches.

What zones can you grow Endless Summer hydrangeas in?

You can grow Endless Summer hydrangeas in Zones 4–8

Do endless summer hydrangeas like sun or shade?

Endless Summer hydrangeas prefer partial shade, with about four hours of direct, unfiltered sun in the morning followed by afternoon shade.

Should you cut back endless summer hydrangeas in the fall?

You don’t need to cut back healthy old wood. Endless Summer hydrangeas can bloom on both old and new wood, making them a rarity among hydrangeas.

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