Endless Summer® is a brand of several cold-hardy reblooming hydrangeas. Their stunning blooms are available in several colors: pink, blue, purple, red, and white. These mophead hydrangea (Hydrangea macrophylla) cultivars bloom on the previous year’s stems as well as the new season’s stems, which is not the typical bloom habit of mophead hydrangeas.
The Endless Summer bloom habit provides flowers from spring through to late summer. With its rounded growth habit and dense, broadly ovate green leaves, it is the perfect flowering shrub for foundation plantings, containers, perennial flower borders, and anywhere in your landscape where you want colorful blooms.
Hydrangeas are toxic to humans and dogs, cats, and horses.
| Common Name | Endless Summer hydrangea |
| Botanical Name | Hydrangea macrophylla Endless Summer |
| Family | Hydrangeaceae |
| Plant Type | Shrub |
| Mature Size | 3-5 ft. tall, 3-5 ft. wide |
| Sun Exposure | Partial sun |
| Soil Type | Loamy, moist, well-drained |
| Soil pH | Acidic, neutral, alkaline |
| Bloom Time | Spring, summer |
| Flower Color | Pink, purple. blue, red, white |
| Hardiness Zones | 4-9 (USDA) |
| Native Area | Cultivar, no native range |
| Toxicity | Toxic to people, toxic to dogs, cats, and horses |
Endless Summer Hydrangea Care
Endless Summer hydrangea is a collection of several Hydrangea macrophylla cultivars that bloom all summer long. Like all hydrangeas, they do best in soil with plenty of organic matter so amending the soil before planting is important for plant health and blooming. After planting, spread a layer of organic mulch around the plant to help retain moisture and add nutrients to the soil. When spreading mulch, be sure that it doesn't touch the base of the plant.
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Light
Endless Summer hydrangeas grow best in partial sun. A location that receives morning sun and dappled afternoon shade is ideal. If these hydrangeas are planted in full sun, conditions might be too hot and intense for the plants to produce blooms. Planting in too much shade can result in weak stems and fewer blooms.
Soil
Nutrient-rich, well-drained soil is ideal for Endless Summer hydrangeas. While these flowering shrubs tolerate a wide pH range (4.5 to 7.5), they tend to thrive in soil that is slightly acidic.
Except for the Endless Summer 'Blushing Bride' variety, which has white blooms, the soil pH level and aluminum content determines bloom color. A soil pH below 6.0 produces blue blooms, and a soil pH above 6.0 produces pink blooms.
Be aware that if you add a sulfur-based soil acidifier to lower soil pH, adding too much aluminum sulfate can increase the salinity of the soil, which might prevent the hydrangea from blooming. Contact your local extension office to conduct a complete soil test to check that the salinity (EC) is between 1 and 3.
Be aware that results from adjusting soil pH are not instantaneous, it might take a season or two for the amendments to take effect.
Water
Endless Summer hydrangeas have medium to high water needs. Throughout the growing season, the soil should be kept evenly moist but not waterlogged. Ensuring the plant has proper drainage is imperative to prevent root rot.
Endless Summer hydrangeas make gorgeous container plants. Just keep in mind that they will need significantly more water during the growing season than garden-grown plants.
Temperature and Humidity
Endless Summer hydrangeas are hardy in USDA hardiness zones 4 to 9, making them available for most North American gardeners.
Unlike other hydrangea varieties, Endless Summer hydrangeas have excellent winter hardiness and can withstand winter temperatures as low as -30 degrees Fahrenheit (or -34.4 degrees Celsius) at the coldest. This means that flowering is quite reliable regardless of winter temperatures.
Fertilizer
The general recommendation for feeding your hydrangea is to apply one cup of a granular fertilizer in spring or early summer to promote plant health. Any more than that is overkill. Over-fertilizing can burn the root system and actually inhibit bloom production.
Use a granular, slow-release fertilizer with an NPK ratio of 10-30-10, which contains a higher percentage of phosphorus. Phosphorus is the middle number in the NPK ratio. If you cannot find that specific nutrient combination, look for a fertilizer that has a higher ratio of phosphorus (P) than the other two nutrients. Phosphorus promotes blooming.
Do not use a fertilizer with a higher percentage of nitrogen (N) because that can result in lush foliage but few blooms.
Types of Endless Summer Hydrangeas
The Endless Summer collection contains several cultivars. The 'Original Bigleaf Hydrangea' was the first re-blooming hydrangea discovered and it remains the most well-known and widespread .
- Hydrangea macrophylla 'Original Bigleaf Hydrangea' : This variety grows three to five feet tall and wide with blue, purple, or pink blooms.
- Hydrangea macrophylla 'Twist-n-Shout®': This variety has a lacecap flower form and grows three to five feet tall and up to four feet wide with deep pink or periwinkle blue blooms.
- Hydrangea macrophylla ''Summer Crush®': This compact variety can tolerate more sun than the other varieties and grows 18 to 36 inches tall and wide with raspberry red or neon purple blooms.
- Hydrangea macrophylla 'BloomStruck®' : This variety grows three to five feet tall and up to six feet wide with vivid rose-pink, blue, or purple blooms.
- Hydrangea macrophylla ‘Blushing Bride' This is the only variety where soil pH cannot change the initial bloom color. This variety grows three to four feet tall and wide with pure white blooms, which mature to blush pink or Carolina blue.
Pruning
Endless Summer hydrangeas require minimal pruning. Never prune them in the fall. If at all, spring is the time to prune without the risk of removing flower buds. Wait until green leafy growth appears on the stems. Make sure to remove only dried out brown buds located higher up on the stems. Don't remove the green buds on the lower part of the stems, as these will be the first buds to bloom. The new stem growth occurs at the base of the plant and this where blooms will emerge later in the summer.
Propagating Endless Summer Hydrangeas
The Endless Summer collection is a registered trademark and propagating it by cuttings or seeds is prohibited by a plant patent.
Overwintering
Endless Summer hydrangeas are hardy to USDA cold hardiness zone 4 and need no winter protection when grown in the garden. The exception is when the plants are container grown. To prepare your container-grown Endless Summer hydrangea for overwintering, stop fertilizing them around the end of July or early August. Don't prune them in the fall.
In cold climates, overwinter the container in a sheltered location such as an unheated garage, greenhouse, shed, or basem*nt. For containers that are too large to move, cover the base with a thick layer of mulch and wrap the container in burlap or another thick textile to insulate it from the cold.
If you live in a warmer climate, leave the potted hydrangea outdoors but move it to a location where it is protected from chilling winter winds.
Water the plants about once every month; they don't need much water during the winter but don't let them dry out. If you leave them outdoors, water them if rainfall is sparse.
Common Pests and Plant Diseases
Endless Summer hydrangeas are susceptible to a few common pests and diseases which include powdery mildew, bud blight, leaf spot, bacterial wilt, aphids, Japanese beetles, spider mites, and slugs. Each of these common ailments can be successfully eliminated with proper treatment. Prevent powdery mildrew by providing plenty of air circulation around plants.
Remove aphids or spider mites with a blast of water from the hose or a shot of insecticidal soap. Hand pick beetles from the plants and drop them into soapy water. Lure slugs away from plants with baits or spread a ring of diatomaceous earth around the base of the plant (this only works in dry conditions).
Ensure that you examine your hydrangeas regularly in an effort to catch any diseases or pests early before they become infestations.
FAQ
How do you keep Endless Summer hydrangeas blooming?
The best location to ensure continuous bloom is one where the plant receives morning sun and afternoon dappled shade. In too much sun, they might stop blooming.
Do you deadhead Endless Summer hydrangeas?
Endless Summer hydrangeas benefit from deadheading to make room for the next bloom. Remove the spent flowers just below the flower head and above the next set of leaves.
How long does it take to change the flower color of an Endless Summer hydrangea?
It depends on the pH level of your soil. If your soil is alkaline and you want blue flowers, which require a soil below 6.0, it might take one year or more to gradually acidify the soil. If your soil is already in the neutral pH spectrum, around 7.0, soil acidification happens faster and you might see blue flowers in the same season.
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
University of California Agriculture, and Natural Resources. “Toxic Plants (by Common Name).”Ucanr.Edu, https://ucanr.edu/sites/poisonous_safe_plants/Toxic_Plants_by_common_Name_659/
“Hydrangea.”ASPCA, https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/hydrangea
“Hydrangea Planting and Care.”Endless Summer, 6 Mar. 2020, https://endlesssummerblooms.com/resource/hydrangea-planting-and-care/
“FAQ.”Endless Summer, 25 Feb. 2020, https://endlesssummerblooms.com/resource/faq/
“How Do I Protect My ENDLESS SUMMER Hydrangea over the Winter?”Extension, https://extension.unh.edu/blog/2017/12/how-do-i-protect-my-endless-summer-hydrangea-over-winter
Insights, advice, suggestions, feedback and comments from experts
Endless Summer® is a brand of cold-hardy reblooming hydrangeas that produce stunning blooms in various colors such as pink, blue, purple, red, and white. These hydrangeas belong to the mophead hydrangea (Hydrangea macrophylla) cultivars and have a unique bloom habit. Unlike typical mophead hydrangeas, Endless Summer hydrangeas bloom on both the previous year's stems and the new season's stems, providing flowers from spring through late summer [[1]].
These hydrangeas are known for their rounded growth habit, dense foliage with broadly ovate green leaves, and vibrant blooms. They are versatile flowering shrubs suitable for various landscaping purposes, including foundation plantings, containers, perennial flower borders, and other areas where colorful blooms are desired [[1]].
It's important to note that hydrangeas, including Endless Summer hydrangeas, are toxic to humans and pets such as dogs, cats, and horses [[1]].
Key Concepts:
- Endless Summer® is a brand of cold-hardy reblooming hydrangeas.
- They bloom on both the previous year's stems and the new season's stems.
- They come in various colors: pink, blue, purple, red, and white.
- They have a rounded growth habit and dense, broadly ovate green leaves.
- They are toxic to humans and pets.
Now, let's address the concepts mentioned in the article.
Light Requirements:
Endless Summer hydrangeas thrive best in partial sun. It is ideal to plant them in a location that receives morning sun and dappled afternoon shade. While full sun conditions may be too hot and intense for these hydrangeas to produce blooms, planting them in too much shade can result in weak stems and fewer blooms [[2]].
Soil Requirements:
Endless Summer hydrangeas prefer nutrient-rich, well-drained soil. They can tolerate a wide pH range (4.5 to 7.5), but they tend to thrive in slightly acidic soil. The bloom color of most varieties is determined by the soil pH level and aluminum content. A soil pH below 6.0 produces blue blooms, while a soil pH above 6.0 produces pink blooms. It's important to note that adjusting soil pH takes time, and the amendments may take a season or two to take effect [[2]].
Watering:
Endless Summer hydrangeas have medium to high water needs. Throughout the growing season, it is important to keep the soil evenly moist but not waterlogged. Proper drainage is crucial to prevent root rot. Container-grown hydrangeas require more water than those planted in the ground. It is recommended to water them about once a month during the winter, ensuring they don't dry out [[3]].
Temperature and Hardiness:
Endless Summer hydrangeas are hardy in USDA hardiness zones 4 to 9, making them suitable for most North American gardeners. They have excellent winter hardiness and can withstand temperatures as low as -30 degrees Fahrenheit (-34.4 degrees Celsius) at the coldest. This makes them reliable for flowering regardless of winter temperatures [[4]].
Fertilizing:
To promote plant health, it is generally recommended to apply one cup of a granular fertilizer with an NPK ratio of 10-30-10 in spring or early summer. Over-fertilizing can burn the root system and inhibit bloom production. It's important to avoid using a fertilizer with a higher percentage of nitrogen (N) as it can result in lush foliage but fewer blooms. Phosphorus (P) promotes blooming, so a fertilizer with a higher ratio of phosphorus is preferred [[5]].
Pruning:
Endless Summer hydrangeas require minimal pruning. It is best to prune them in spring when green leafy growth appears on the stems. Only remove dried out brown buds located higher up on the stems, while leaving the green buds on the lower part of the stems. The new stem growth at the base of the plant will produce blooms later in the summer [[6]].
Propagation:
Propagation of the Endless Summer collection by cuttings or seeds is prohibited due to a plant patent [[7]].
Overwintering:
Endless Summer hydrangeas are hardy in USDA hardiness zone 4 and do not require winter protection when grown in the garden. However, container-grown plants may need some extra care. In cold climates, it is recommended to overwinter the container in a sheltered location such as an unheated garage, greenhouse, shed, or basem*nt. For large containers that cannot be moved, insulate the base with mulch and wrap the container in burlap or another thick textile. In warmer climates, potted hydrangeas can be left outdoors but should be protected from chilling winter winds. Watering should be reduced during the winter, but the plants should not be allowed to dry out completely [[8]].
Common Pests and Diseases:
Endless Summer hydrangeas are susceptible to common pests and diseases such as powdery mildew, bud blight, leaf spot, bacterial wilt, aphids, Japanese beetles, spider mites, and slugs. Proper treatment can help eliminate these issues. Providing adequate air circulation, removing pests manually or with insecticidal soap, and using appropriate treatments can help maintain the health of the plants [[9]].
FAQ:
- The best location to ensure continuous bloom for Endless Summer hydrangeas is one where the plant receives morning sun and afternoon dappled shade. Too much sun may cause them to stop blooming [[10]].
- Deadheading (removing spent flowers) can benefit Endless Summer hydrangeas by making room for the next bloom. Spent flowers should be removed just below the flower head and above the next set of leaves [[10]].
- The time it takes to change the flower color of an Endless Summer hydrangea depends on the pH level of the soil. Acidifying the soil to achieve blue flowers (pH below 6.0) may take one year or more, while neutral pH soil (around 7.0) may result in blue flowers in the same season [[10]].
I hope this information helps you understand the concepts mentioned in the article about Endless Summer hydrangeas. If you have any further questions, feel free to ask!
