Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla ‘Bailmacsix’)

The new Pop Star cultivar is a lacecap bigleaf hydrangea in an easy-care compact size. It is cold hardy to USDA zone 4, and comes in blue but the flowers can be turned pink with alkaline soil. The small size makes it a good choice for a patio container.

I. Appearance and Characteristics

The Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla ‘Bailmacsix’) is a cultivated variety of the bigleaf hydrangea, a deciduous shrub from Asia belonging to the Hydrangeaceae family. Pop Star is part of the Endless Summer collection of reblooming hydrangeas, and was introduced to the market in 2023 after years of trialing and review. It stands out for its easy upkeep, compact size, and consistency in producing repeat blooms.

Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla 'Bailmacsix')

Pop Star is a small and compact lacecap hydrangea, growing only 13-36 inches tall and wide. It has the ability to bloom on both old and new wood, flowering repeatedly from late spring through fall despite extreme winter cold snaps and unpredictable spring freezes. It is a prolific bloomer, with showy flowers covering the entire plant from top to bottom and strong stems which prevent the plant from flopping over. Flowers are either electric blue or bright pink, depending on the soil pH. The intricate flat-topped blossoms are comprised of tiny fertile flowers surrounded by showy sterile florets. Bees, butterflies and other pollinators flock to these small fertile inner blooms. Pop Star is a moderately fast-growing hydrangea, adding 13 – 24 inches of growth per year and maxing out at 36 inches tall in maturity.

II. How to Grow and Care

Sunlight

This new cultivar blooms in partial shade, so a sun-dappled shady area of the garden is a good spot for it. It would also do well in an area with several hours of morning sun, but afternoon sun in the summer may prove too hot and strong for this shade-loving hydrangea.

Because of its compact size, you can also plant this shrub to get more or less sunlight based on its location and proximity to trees or taller shrubs. You can also try growing this small shrub in a container, giving you flexibility for its location. Observe the movement of sunlight in your yard through the seasons to determine the best spot.

Temperature and Humidity

This cold-hardy shrub will perform best within the growing zone range of 4 through 9 (USDA). If your summer days tend to get a bit hot (as happens more often in the Northeast), plant your Pop Star hydrangea where it will get morning sun instead of afternoon sun. Temperate zone humidity should not bother this sturdy plant. If you note any powdery mildew, this is more likely due to lack of air circulation, as opposed to too much humidity.

Watering

Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla 'Bailmacsix')

Water your Pop Star hydrangea well after planting, and water regularly for 2 to 3 weeks until it is established. After that, water as you would the rest of your garden, making sure it gets some additional water if there’s a lack of rain for more than a few days.

Soil

The main factor to consider when growing macrophylla hydrangeas is whether you want to amend your soil to affect the bloom color. Acidic soils will usually yield a blue flower, whereas alkaline soils produce a pink flower.

To make soil more acidic, add some aluminum sulfate or wettable sulfur to your soil area. Other natural amendments such as peat moss, pine needles, or coffee grounds can also raise soil acidity slightly. To make soil “sweeter” or more alkaline, use powdered lime or crushed limestone.

Fertilizing

Your Pop Star hydrangea will likely have some fertilizer granules in the soil in the container when you purchase it. Therefore, wait until your shrub has been established for several months to a year before applying any extra fertilizer. (It’s always best to perform a soil test before adding any fertilizer to ensure you aren’t overfertilizing.)

A regimen of organic, balanced 10-10-10 NPK fertilizer (which provides equal amounts of nitrogen, potassium and phosphorous) is recommended for the Pop Star hydrangea. This can be applied with plenty of water in early spring, and, if desired, again in early August before reblooming occurs. Don’t fertilize after mid-August to allow the plant to prepare for its winter dormancy.

Pruning

Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla 'Bailmacsix')

The best time to prune bigleaf hydrangeas is in late autumn (late November or early December) after blooms have begin to fade. You can also prune lightly in early spring but be mindful of any buds that have begun to form. These shrubs should be pruned lightly just to maintain shape, or to remove dead or broken branches

Growing in Containers

These compact shrubs do very well in containers on your patio. Make sure you choose a container that will give the roots some space to grow, and repot the hydrangea every other year, or as it begins to outgrow its container, and refresh the soil each time you repot it.

Mulching

Apply a layer of organic mulch around the base of the plant to retain soil moisture, regulate temperature, and suppress weeds. Make sure the mulch does not touch the base of the plant.

Overwintering

To protect your hydrangea’s roots during a cold winter, put a 3- to 4-inch layer of natural mulch (wood chips, pine straw and leaves all work fine, alone or mixed together) around the base. If your

Pop Star hydrangea is in a container, shifting it to a larger container for winter is a good idea, as the container’s soil will likely freeze, which can damage the roots. It’s recommended to move the container to a sheltered, slightly warmer space such as a shed, garage or basement, where it will stay cool but not freeze. Give it a small amount of water every few weeks, just barely moistening the soil, as this also helps protect the roots

How to Get to Bloom

Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla 'Bailmacsix')

One of Pop Star hydrangea’s most appealing characteristics is its ability to rebloom. New buds will appear just four weeks after being deadheaded. It’s tight growth habit makes the flowers, not the foliage, the focus.

Some gardeners find bigleaf hydrangeas shrubs to be somewhat challenging in the garden, and their most common issue is a failure to flower consistently. The underlying reason for lack of flowering is often that the buds have been damaged by cold temperatures, but with the cold hardiness of the new Pop Star cultivar, this shouldn’t be too much of a problem.

Using a basic balanced organic fertilizer once or twice during the growing season should be sufficient. In addition to early spring and late summer (early August), you could also feed once more in early May and see if that gives an added boost to the flowers. But wait until your plant has been established for a year or so to get a sense of the timing for its blooms, before beginning a fertilizer regimen. (And it’s a good idea to perform a soil test before fertilizing).

Pests and Diseases

Although the Endless Summer hydrangeas are considered very disease-resistant, there are some pests and diseases that occasionally affect macrophylla hydrangeas. These may include leaf spot (Cercospora or Phyllosticta hydrangea), powdery mildew, bud blight, and leaf rust.

In addition, common pests that may affect hydrangeas include Japanese beetles, slugs and aphids. Most of these conditions or pests can be addressed with simple non-toxic treatments. Sufficient air circulation helps prevent powdery mildew, so when planting, leave some space around the shrub.

III. Uses and Benefits

Foundation Planting: Plant Pop Star along side the foundation of your house. Its compact size makes it perfect for using as a facer plant in front of taller evergreen shrubs, or use it to line walkways, sidewalks or driveways.

Mixed Borders: Create a mixed border planting by combining Pop Star with other complementary perennials, ornamental grasses, deciduous and evergreen shrubs for four seasons of color and texture.

Endless Summer Pop Star Reblooming Hydrangea (Hydrangea macrophylla 'Bailmacsix')

Mass Planting: Plant Pop Star hydrangeas in groupings to create a mass of color. This approach works well in large garden beds or alongside pathways and fences, providing a striking visual impact.

Woodland Garden: The dappled shade underneath the canopy of tall trees is an ideal spot for the Pop Star hydrangea. Combine with other partial-shade loving plants like camellias, Japanese andromeda, azaleas, and rhododendrons.

Accent Planting: Use Pop Star as a focal point in the landscape. Plant strategically to draw attention to specific areas of the garden, like entryways, water features, pathways, or seating areas.

Containers: With its compact size, Pop Star is a natural fit for decorative pots and planters. Pair with spillers like sweet potato vine and trailing lobelia.

«
»