The "Popstar" hydrangea is a specific cultivar of the Hydrangea macrophylla species, which is commonly known as bigleaf hydrangea or mophead hydrangea. It's named "Popstar" due to its vibrant and eye-catching flower clusters. Here's some information about the Popstar hydrangea:

1. Appearance: Popstar hydrangeas produce large, rounded flower clusters that consist of densely packed, star-shaped florets. The flowers typically have a mix of pink, purple, or blue hues, depending on the soil pH and the availability of aluminum ions in the soil. The foliage is dark green and glossy, providing a lush backdrop for the colorful blooms.

2. Growing Conditions: Popstar hydrangeas prefer partial shade to filtered sunlight, especially in hot climates. They thrive in well-draining, moist soil that is rich in organic matter. These hydrangeas benefit from regular watering, particularly during dry periods, to keep the soil consistently moist. They can be grown in USDA Hardiness Zones 5-9.

3. Soil pH and Flower Color: The flower color of Popstar hydrangeas can be influenced by the soil pH. In acidic soil with a pH below 6.0, the flowers tend to be blue. In neutral to slightly alkaline soil with a pH above 6.0, the flowers may be pink or purple. To manipulate the flower color, you can adjust the soil pH by amending it with aluminum sulfate for blue flowers or lime for pink flowers.

4. Pruning: Pruning Popstar hydrangeas is typically done after flowering. Remove spent flower heads to encourage new growth and maintain a neat appearance. Avoid heavy pruning, as this can reduce flowering the following year, as bigleaf hydrangeas produce flowers on old wood.

5. Uses: Popstar hydrangeas are popular choices for adding color and texture to garden borders, foundation plantings, and mixed shrub borders. They also make excellent cut flowers for floral arrangements, providing long-lasting blooms with a bold presence.

Overall, the Popstar hydrangea is prized for its stunning flower clusters and lush foliage, making it a favorite among gardeners looking to add beauty and charm to their landscapes.