Updated at: 26-05-2022 - By: Sienna Lewis

Reblooming Endless Summer® hydrangeas feature gorgeous blooms in shades of pink, blue, purple, red, and white that are cold-hardy. With this mophead hydrangea cultivator, gardeners in North America will be able to enjoy beautiful flowers from early spring through late summer on branches from the previous year as well as new season growth.

Endless Summer® Hydrangea Care

It takes four years for Endless Summer® hydrangeas to reach their full potential of four feet in height and three to five feet in spread, and they are deciduous shrubs with rounded growth habits. You may use these shrubs in a variety of ways, such as foundation plants, hedges and containers, as well as in border gardens and other areas. Supply a layer of organic mulch over the soil to help retain moisture and add nutrients to the soil during the growing season to better protect these flowering plants.


Full sun to partial shade is ideal for Endless Summer® hydrangeas. The best site is one that gets morning sun and afternoon shade. Too much sunlight might cause plants to produce fewer flowers throughout the season.

Caring for Endless Summer Hydrangea


Endless Summer® hydrangeas thrive in soil that is rich in nutrients and well-drained. Even though these flowering shrubs are able to thrive in a wide variety of pH levels, they prefer slightly acidic soils.

Keep in mind that the color of the blooms will be determined by the soil’s pH. The Original Endless Summer® hydrangea, for example, bears blue blossoms in acidic soil and pink flowers in alkaline soil, as shown in the diagram. This means that you can change the pH of the soil according on the color of the blooms you like.


These hydrangeas have medium to high water requirements. The soil should be kept evenly moist, but not soggy, during the growing season. Root rot can be prevented by ensuring that the plant has adequate drainage. Endless Summer® hydrangeas require substantially more water when planted in containers than when cultivated in the garden.

Temperature and Humidity

Most North American gardeners will be able to cultivate Endless Summer® hydrangeas because they are hardy in USDA zones 4 through 9.

Endless Summer® hydrangeas can tolerate temperatures as low as -30 degrees Fahrenheit (or -34.4 degrees Celsius) in the winter, making them more hardy than other hydrangea cultivars. This means that even if temperatures drop below freezing in the winter, flowering will still occur.


Endless Summer® hydrangeas require a lot of fertilizer to develop and thrive. In the spring or early summer, use a balanced NPK fertilizer to encourage new growth.

While fertilizers high in ammonium nitrate or ammonium sulfate can be used to lower soil pH and make the soil more acidic, fertilizers with lime can help to raise soil pH and make the soil more alkaline, hence controlling the color of flowers.

Endless Summer® Hydrangea Varieties

Among the Endless Summer® hydrangeas are five types. First re-blooming hydrangea, the Original remains the most popular and common type.

  • Hydrangea macrophylla ‘Bailmer,’ the Original Bigleaf Hydrangea, grows in the wild.
  • Water hyacinth Hydrangea macrophylla ‘PIIHM-I’, also known as the Twist-n-Shout Hydrangea.
  • In the summertime, hydrangeas are in full bloom, and they’re known as “Summer Crush” because of the color of their leaves.
  • Large-leafed Hydrangea – Hydrangea macrophylla ‘PIIHM-II’, often known as the ‘BloomStruck’ variety
  • Bubbly Maid of Honor Hydrangea macrophylla ‘Blushing Bride’ – Hydrangea macrophylla


Pruning Endless Summer® hydrangeas is not necessary, and it should not be done when the plant is actively growing. Because they bloom from both old and new wood, these hydrangeas are able to endure extensive pruning. A good rule of thumb is to wait until late summer or early fall, when the flowering season has ended.

How to Grow Endless Summer® Hydrangeas From Seed

The seed of Endless Summer® hydrangeas can be acquired from a nursery or taken from existing plants and successfully cultivated. Start your seeds indoors in cell packs or seed starting pots for the greatest results. Keep the soil moist at all times by gently sowing the seeds over the top layer of the soil. You don’t have to worry about incorporating the seeds into the soil.

Warm, indirect light is ideal for seedlings, so keep them in this place. To transplant the seedlings into the garden or an outdoor container, wait until they have formed strong roots.

Keep in mind that mature Endless Summer® hydrangea shrubs can grow to a height of four feet and a width of three to five feet when deciding where to plant your hydrangea.

Everything You Need to Know About Endless Summer Hydrangeas - This Old House

Common Pests and Diseases

These hydrangeas are vulnerable to several common pests and diseases, including powdery mildew and bud blight. They are also vulnerable to bacterial and fungal diseases, including as leaf spot, bacterial necrosis, and bacterial wilt. With correct therapy, each of these disorders can be removed.

You should inspect your hydrangeas on a frequent basis in order to catch any pests or illnesses before they have a chance to spread and become an issue.

Hydrangea Planting and Care

Perennial shrubs that re-bloom throughout the spring and summer months are part of the Endless Summer® Hydrangeas collection, which adds more aesthetic interest to your garden. It is known that Endless Summer® Hydrangeas bloom for 10 to 12 weeks longer than the usual Hydrangea macrophylla plant, which makes them ideal for cooler climes. To get you started, here are some general rules for growing hydrangeas:

Site Selection

Before planting your Endless Summer macrophylla, stroll around your yard and take note of any existing plants, the amount of space you have, and any spots that may use some color. The area where you plant these hydrangeas, especially in northern regions, is critical to their flower production. Hydrangeas can withstand more sun in Zones 4-5a if you live further north. Plant your macrophylla in an area that receives full morning light but has partial afternoon shadow. Hydrangea macrophylla is less tolerant of bright sunlight the further south you dwell. Allow for 2-3 hours of morning sun, followed by dappled or partial shade in the afternoons.

Soil Preparation

Besides the climate, the most critical element in growing plants is the soil. The health of your plants and the quantity and quality of their flowers are directly related to how well your soil has been prepared. To get started, you need to know what kind of soil you’re dealing with. Ask your local nursery for a soil-testing kit. The “Jar Test” is a different kind of at-home test. Remove 14 cup of soil after 4 inches of digging. In a transparent jar or plastic bottle, add 2 cups of water and a few drops of dishwashing soap. One minute of shaking and then 24 hours of letting the contents settle is all that is required. Bottom sediment is sand, with silt and clay making up the following two layers; the top layer may seem yellow-brown, red or tan.

  • If your jar contains more than half sand, you have sandy soil.
  • Heavy silt is defined as having less than half clay and more than half silt.
  • Clay: If you have ¼ clay and a good amount of silt, you have clay soil.

You have clay soil if you have at least a quarter of your soil made up of clay and silt.

Planting Hydrangeas

Once the dirt has been prepared, set out the plants according to your plan. Make sure that the plants will barely touch when they’re grown to their full size. This will give your landscape a full appearance while yet allowing air to flow through it. Prior to planting, add any fertilizer (see below), organic material or nutrients to your soil mix to enrich the mix before placing your hydrangea macrophylla in place. The hydrangea macrophylla’s roots should be lightly loosened with your fingers before planting in order to facilitate root growth and spread. Ensure that the crown of the plant is level with the ground at the point where the stems’ base touches the dirt. The hydrangea can quickly dry out if it is placed too high. Hydrangeas may not bloom or may even decay if the crown is planted too low. Fill up the hole and pack the soil tightly around the crown of the hydrangea to create a barrier to keep water out. Refill the dam after it has been allowed to drain.


The best time to fertilize hydrangeas is in the spring or early summer. Phosphorus-rich granular fertilizer is the best option for slow-release fertilization (the middle number in the NPK ratio). The presence of phosphorus in the soil promotes the growth of flowers. When applying fertilizer, be sure to follow the directions on the container and avoid using too much. Hyacinths can have large, green leaves if they are over-fertilized.


Overwatering might cause hydrangea macrophylla macrophylla macrophylla macrophylla to produce less blooms. The frequency and amount of water you use will need to be adjusted based on the type of soil you have. In comparison to sandy or loam soils, clay soils hold more water and have higher rates of runoff because it doesn’t allow as much water to sink in. When the ground is dry, water the shrubs using a drip irrigation system, a soaker hose, or by hand. You may notice your hydrangeas looking droopy in the afternoon, but they’ll come back to life as soon as the weather cools down. If you water your plants in the morning or in the evening, they will be better able to survive because of the calmer breeze and lower temperatures during these times of day. Another technique to conserve water and keep the ground cool is to use mulch. It is common for mulched plants to go longer between waterings than unmulched plants.

Blue or Pink Blooms

The ability of an Endless Summer hydrangea to change the color of its blossoms is one of its most appealing characteristics. It is possible to detect the pH level of your soil with a simple soil test from a local nursery. Other than Blushing Bride, which is a white hydrangea, soil with a pH below 6.0 (acidic soil) will produce blue hydrangea blooms and a pH above 6.0 will produce pink hydrangea flowers. Your hydrangea colors can be altered to suit your personal style! This product is developed to alter the color of your flowers. Color Me Pink™ adds garden lime to the soil to raise the pH level and produce pink hydrangea flowers. Color Me Blue™ adds soil sulfur to encourage blue hydrangea bloom development. These products are safe, organic and all-natural. There are also other natural remedies to changing hydrangea colors. To encourage blue blooms in alkaline soils, add aluminum sulfate, composted oak leaves, pine needles or coffee grounds. To encourage pink blooms in acidic soil, add wood ashes, lime or fertilizers with high levels of phosphorus (a ratio of 25-10-10 is best) to prevent aluminum from entering the plant’s system.

How to Prune Hydrangeas

If you’re looking for an Endless Summer hydrangea, you’ll be pleased to know that the flowers can change color. A simple soil test from your local nursery can help you identify your pH level, which will affect the color of your hydrangea macrophylla. There are two types of soil that will yield blue and pink blooms: acidic and alkaline. Blushing Bride, which is white, is the only type of hydrangea to thrive in acidic soil. Your hydrangea hues can be changed to match your personal preference! You can modify the color of your flowers with Endless Summer’s formulated product. Pink hydrangea blossoms are produced by adding garden lime to the soil (Color Me PinkTM). Color Me BlueTM is a product that adds soil sulfur to promote blue hydrangea blooms. These items are safe, all-natural, and organic. Some more natural ways to change the color of hydrangeas are also available. Aluminum sulfate, composted oak leaves, pine needles, or coffee grounds can be added to alkaline soils to encourage blue flowers. Wood ashes, lime or fertilizers high in phosphorus (a ratio of 25-10-10) can be added to acidic soils to prevent aluminum from entering the plant’s system and encouraging pink blooms.

Endless Summer The Original Hydrangea | PlantAddicts.com


You should protect your plants against freezing weather if you reside in an area with cold temperatures. The most flowers will be produced by protecting the old wood of Endless Summer® Hydrangeas because they bloom on both new and old wood. After August 1st, do not prune or chop back shrubs. To avoid destroying flower buds that will come up later in the spring and summer, leave the fall blooms on your plants over the winter. You can use leaves, wood mulch, or straw to keep your plants warm. Mulch or leaves should be piled at least 12″ high around your plants to preserve the buds that will bloom in the spring of 2017.

Wait until all risk of frost has passed before removing the mulch in the spring to ensure that the old and new wood produce lovely blossoms. “Old wood” buds and flowers on current season growth will normally begin to bloom six weeks apart and last until fall. Container-planted hydrangeas should be moved to a cool basement or garage for the winter months and cared for similarly to garden-planted hydrangeas. As a result of the lack of snow and rain, container plants will not require as much mulch, but should be watered sparingly during the winter.