How to Grow and Care for Endless Summer® Hydrangea

Endless Summer Hydrangea Care

Here are the main care requirements for growing an Endless Summer hydrangea:

• Amend the soil with plenty of organic matter before planting.
• Select a location with full morning sun and dappled shade in the afternoon.
• After planting, spread a layer of organic mulch around the plant without touching its base.
• Water as needed to keep the soil moist but not wet.
• Fertilize in spring or early summer,
• Prune only minimally in the spring.

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 intense for the plants to bloom. Planting in too much shade results 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 slightly acidic soil.

Except for the Endless Summer ‘Blushing Bride’ variety, which has white blooms, the soil pH level and aluminum content determine bloom color. A soil pH below 6 produces blue blooms, and a soil pH above 6 produces pink blooms.

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.

Temperature and Humidity

Endless Summer hydrangeas are hardy in USDA hardiness zones 4 to 9, where they flourish in average heat and humidity.

Unlike other hydrangea varieties, Endless Summer hydrangeas have excellent winter hardiness and withstand winter temperatures as low as -30 degrees. 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. Over-fertilizing risks burning the root system and inhibits bloom production.

Use a granular, slow-release fertilizer with an NPK ratio of 10-30-10, which contains a higher percentage of phosphorus. 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.

Do not use a fertilizer with a higher percentage of nitrogen (N), which can result in lush foliage but few blooms.

Types of Endless Summer Hydrangeas

The Endless Summer collection contains several cultivars:

• H. macrophylla ‘Original Bigleaf Hydrangea‘ : This was the first re-blooming hydrangea discovered. It grows three to five feet tall and wide with blue, purple, or pink blooms.
• H. 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.
• H. macrophylla ”Summer Crush’: This compact variety tolerates more sun than the other varieties and grows 18 to 36 inches tall and wide with raspberry red or neon purple blooms.
• H. 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.
• BloomStruck hydrangea: This variety grows three to five feet tall and up to six feet wide with vivid rose-pink, blue, or purple blooms.
• Pop Star hydrangea: With a height and width of only 18 to 34 inches, this is a good choice for a patio container. It comes in blue but the flowers can be turned pink with alkaline soil.

Pruning

Endless Summer hydrangeas require minimal pruning. Endless Summer hydrangeas bloom on the previous year’s stems as well as the new season’s stems. 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 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.

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.

Potting and Repotting

Due to their compact size, Endless Summer hydrangeas make excellent potted plants. Use a large pot at least 16 to 24 inches in diameter to adequately fit the root ball of the plant and make sure the pot has large drainage holes.

Fill it with potting mix that already has slow-release fertilizer added to it (if it doesn’t, mix in a slow-release fertilizer NPK ratio of 10-30-10). Potted hydrangeas need frequent watering, possibly daily. Water deeply and slowly until water drips out of the drainage holes.

You may need to repot the hydrangea to a larger pot after three to five years when the roots reach the sides of the container.

Overwintering

Endless Summer hydrangeas are hardy to USDA cold hardiness zone 4 and need no winter protection when grown in the garden. In colder climates, overwinter the container in a sheltered location such as an unheated garage, greenhouse, shed, or basement.

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 wind.

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 precipitation is sparse.

Common Pests & Plant Diseases

Endless Summer is susceptible to a few common pests and hydrangea 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 mildew 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.

How to Get Endless Summer Hydrangea to Bloom

Bloom Months

Depending on the location, endless summer hydrangeas bloom from May through October.

How Long Does Endless Summer Hydrangea Bloom?

While these hydrangeas are repeat bloomers, the weather plays a key role in the the duration of the bloom. Hot, dry weather tends to cut the bloom period short while cooler temperatures encourage a longer bloom.

What Do Endless Summer Hydrangea Flowers Look and Smell Like?

The mophead flower heads are up to 9 inches across, blue when grown in acidic soil, and pink in alkaline soil. The color intensifies as the blooms mature. The flowers have a mild floral fragrance.

How to Encourage More Blooms

Plant the hydrangea in optimal light and soil conditions and make sure it gets enough water and the right fertilizer.

In years with extremely hot summers or severe late spring frosts, Endless Summer hydrangeas might not bloom as expected despite your best efforts but don’t give up, it might bloom to its full potential the next year.

Caring for Endless Summer Hydrangea After It Blooms

There is nothing to be done after the bloom other than winterizing your hydrangea if it’s growing in a container. Above all, do not prune it in the fall, as this will decimate next year’s bloom.

Deadheading Endless Summer Hydrangea Flowers 

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.

Common Problems With Endless Summer Hydrangea

Drooping or Curled Leaves

If your hydrangea has drooping leaves, check the soil moisture, and if it feels dry, water deeply. If the leaves are curled despite the soil being moist, it could be the plant’s natural protective mechanism in daytime temperatures of 90 degrees or higher. The leaves should recover at dusk as it gets cooler.

Yellowing Leaves

Yellowing leaves have several potential causes, including overwatering, underwatering, nutrient deficiency, and improper sun exposure. Run through the list of seven reasons for yellowing hydrangea leaves to determine what is ailing your plant.

Brown Leaf Tips or Edges or Tips

Overfertilization of hydrangeas leads to root burn, which manifests itself as brown edges or tips. Another possible reason is that you added too much aluminum sulfate to change the color of the blooms.

In that case, flush the soil with water to remove the excess salts or fertilizers. Let the soil surface dry for a day or two before watering again, and abstain from fertilizing until the plant shows healthy new leaf growth.