Endless Summer® is a trademarked cultivar of Hydrangea macrophylla. This type of hydrangea is known for blooming profusely throughout the entire summer and even into fall in warmer climates. Bred from bigleaf hydrangea, this popular variety blooms repeatedly throughout the same season, producing flowers on both new and old wood.
Growing Endless Summer Hydrangea in Your Garden
Are you considering adding Endless Summer hydrangeas to your landscape? Find out what you need to know to successfully grow this cold-hardy, deciduous shrub.
When to Plant Endless Summer Hydrangea
With such a long blooming season, Endless Summer hydrangeas need plenty of time to establish their roots in the soil before their blooming season begins. With that in mind, it's best to plant them in fall several weeks before the first freeze or in the early spring.
Where to Plant Endless Summer Hydrangea: Light and Soil Requirements
Endless Summer hydrangeas need to be planted in part shade. The perfect location for these plants is one where they will be exposed to morning sun and afternoon shade. They shouldn't get more than four hours of direct sunlight per day. The type of soil these plants need depends on what color blooms you want. This is because soil acidity impacts the color of hydrangea flowers.
- Acidic soil (pH less than 7.0) leads to blue flowers.
- Neutral soil (pH of 7.0) leads to purple flowers.
- Alkaline soils (pH greater than 7.0) lead to pink flowers.
Test soil acidity and adjust based on your color preference. You can reduce the pH level to increase soil acidity by amending soil with sulfur. To reduce acidity so the soil becomes more alkaline, you'll need to add lime to your soil. This will raise the pH level. (Note: White hydrangeas are not impacted by soil acidity.)
Watering and Fertilizing Endless Summer Hydrangea
Wondering when to fertilize Endless Summer hydrangeas and how often to water them? If a hydrangea does not get sufficient water, its leaves will turn black. These plants need frequent watering, but only need to be fertilized annually.
- Hydrangeas plants need to be watered at least once per week.
- It's best to water them twice weekly when the temperatures are high and conditions are dry.
- Fertilize your hydrangeas once during the spring or early summer using a slow-release tree/shrub fertilizer.
- You could opt to use a balanced 10-10-10 NPK fertilizer instead of tree/shrub fertilizer.
Troubleshooting Hydrangea Bloom Issues
If your Endless Summer hydrangea is not blooming, this issue is likely caused by one of three problems.
- Too much shade - Hydrangeas will not bloom if they don't get enough sun. They can't be planted in full sun, but they also shouldn't be planted in full shade. Consider moving your plants to a location where they are exposed to the sun during morning hours followed by dappled shade during other times of the day.
- Too much water - Hydrangeas need to stay moist, but there is such a thing as too much of a good thing. Avoid watering too frequently. Hold off on watering when your plants are getting enough water from rain. Check the soil to verify if it drains properly. If it doesn't, amend it with organic matter to improve draining.
- Too much fertilizer - More is not merrier when it comes to fertilizer. Don't add plant food to your hydrangeas every time you feed other garden plants. A single spring feeding is sufficient for these plants. Doing more will result in fewer (or no) blooms rather than more.
Pruning Endless Summer Hydrangea
Endless Summer hydrangea plants should be pruned very early in the spring as soon as you start to see green growth on stems. Keep in mind that this plant blooms on both old and new growth before you start pruning.
- Look at each stem carefully, noting if they have soft, green flower buds on them. The ones that do will produce flowers and leaves in the coming months.
- Look at the nodes on the stem to identify which stems have both green and brown buds on them.
- The green ones are old wood buds. They produce the season's first blooms on an Endless Summer hydrangea.
- The brown buds are the ones that are not alive. They are the ones that need to be pruned off.
- Prune your plant between the last green bud and first brown bud on each stem that has both types. Make your cut just above the final green bud.
- After the old wood blooms fade, then it will be time to prune them.
Note: Stems that have only green buds and short stems at the plant's base or that only have leaves so far represent new growth. They will bloom after the old wood flowers fade, so they don't need to be pruned. This will help maximize your plant's flower production throughout its long blooming season.
Endless Summer Hydrangea Pests and Diseases
Diseases and pests aren't a huge issue with Endless Summer hydrangeas, but there are a few concerns that you should be aware of if you are going to grow them.
Common Hydrangea Diseases
Examples of common hydrangea diseases and pests are listed below. Root rot is a serious issue that can kill the plant, but the others primarily pose cosmetic concerns.
- Bacterial wilt (Pseudomonas solanacearum) - This bacteria leads to blight on young hydrangea blooms and leaves. It is most likely to manifest after extended heavy rainfall that occurs during very hot weather.
- Blister rust (Pucciniastrum hydrangea) -This fungus leads to the presence of orange spores forming on the bottom of hydrangea leaves. There are usually a lot of these sports on affected leaves.
- Botrytis blight (Botrytis cinerea) - This fungus leads to brown blotches and/or fuzzy gray fungal growth on hydrangea flowers and buds. It can also lead to leaf spot when affected flower buds or petals fall onto leaves. Botrytis blight is most likely to occur when the weather is wet, cool, and humid. It spreads via wind, so removing and destroying affected flowers, buds, and leaves can help control this issue.
- Powdery mildew (Microsphaera penicillata) - This disease manifests in the form of a powdery white fungal growth that appears on leaves, which can also be paired with purple or yellowy blotches. Powdery mildew is most likely to occur when plants are in humid conditions, such as when shrubs are too close to one another or otherwise crowded. Remove and destroy affected leaves. Treat with neem oil or another essential oil spray.
- Root rot (Armillaria spp.) - Root rot is most likely to occur when plants experience drought conditions. The best way to prevent it is to water your plants sufficiently, especially during extended periods of dry, hot weather. If a hydrangea plant develops wilting shoots that don't bounce back after being watered, chances are that it has root rot. This will ultimately kill the plant.
Common Insect Infestations
Hydrangeas are prone to be infested by a number of common insect pests that plague various types of plants. Examples of insects that commonly target hydrangeas include:
- Aphids (Aphidoidea) - When aphids feed on hydrangeas, the leaves become discolored. Their waste secretions can attract ants as well as cause sooty mold to form, which keeps sunlight from reaching affected parts of the plant.
- Black vine beetle - (Otiorhynchus sulcatus) - In larva and grub form, these weevils eat the roots of hydrangeas. Severe black vine beetle infestations can kill hydrangeas. The leaves turn yellow and then brown before the plant dies.
- Hydrangea leaftiers (Exartema ferriferanum/Olethreutes ferriferana) - These brown and white moths lay eggs on hydrangeas in the spring. They hatch as caterpillars that feed on the plant's leaves and buds, leading to reduced flower production.
- Four lined plant bugs (Poecilocapsus lineatus) - These bugs lay their eggs on hydrangea plants and feed on the plant from the time they hatch through adulthood, when they lay more eggs. Their feeding causes leaf spots and holes in leaves.
- Tarnished plant bug (Lygus lineolaris) - This bug impacts hydrangeas the same way as four-lined plant bugs. Tarnished plant bugs may be even more pervasive because they typically produce multiple generations each year.
Propagating Endless Summer Hydrangea
Hydrangeas can be propagated via stem cuttings, but exercise caution with this variety due to the fact that the name is trademarked and some varieties are still patented. It is not legal to propagate a patented plant. The first Endless Summer cultivated variety was patented in 2001. Plant patents expire after 20 years, so this cultivar's patent expired in 2021. The Endless Summer varieties other than the one known as "The Original" are still patented, so it is not lawful to propagate them. Additionally, the Endless Summer name is trademarked. Even for the variety that is no longer patented, the name "Endless Summer" can only be used by license holders.
Beautiful Endless Summer Hydrangea to Grow in Your Garden
The first Endless Summer variety introduced is now referred to as The Original Endless Summer hydrangea. It grows to three to four feet tall and has an equivalent spread. Other varieties that have been developed and patented since it include:
Endless Summer BloomStruck® variety is a repeat blooming variety. It blooms multiple times during the summer and often continues into fall. This variety reaches three to four feet tall with a spread of four to five feet.
Summer Crush® is a compact hydrangea, reaching only about two to three feet tall with an equivalent spread. It can be planted in-ground or grown in a container. Its flowers have more vivid and intense colors than other hydrangea varieties.
Twist-n-Shout® is a lacecap hydrangea rather than a mophead (which is what the other Endless Summer varieties are). Lacecaps have both large flowers and small florets on the same stem. They reach three to five feet tall and spread three to four feet.
Good Companions for Endless Summer Hydrangea
If you want to place companion plants near your hydrangeas, consider the fact that hydrangeas need part shade and are large enough to create additional shade for smaller plants planted beside or in front of them.
- Understories - Shade-loving plants like astilbes and hostas make great perennial companions for hydrangeas. They thrive in the same reduced light conditions as hydrangeas.
- Shrubs - If you're looking to pair other shrubs with hydrangeas, azaleas are a great option. They generally bloom before hydrangeas, so they'll extend the color in your landscape beyond what hydrangeas provide.
- Trees - Are you looking for ideas for trees to plant near your hydrangeas? Japanese maple and dogwood trees are particularly good tree companions for hydrangeas, because they grow well in part shade.
Add Long Blooming Hydrangeas to Your Landscape
All hydrangeas are beautiful, but they don't all bloom for as long or as profusely as the Endless Summer type. If you're looking to add sizeable summer-long blooming plants to somewhat shaded parts of your landscape, you cannot go wrong with this amazing shrub.