The ‘Shooting Star’ Hydrangea (Hydrangea serrata ‘Shiro-fuji’ or Hydrangea macrophylla ‘Hanabi’) is a deciduous shrub known for its distinctive blooms. Its delicate yet striking appearance makes it a favored choice for many gardens.
Distinctive Features of Shooting Star Hydrangea
The ‘Shooting Star’ Hydrangea is recognized for its unique flower morphology, which gives it its common name. Its blooms are a double lacecap type, featuring prominent white, star-like sepals that “shoot” outwards from the flower head, creating a fireworks-like effect. These showy outer florets surround a central cluster of smaller, fertile flowers that can vary in color from blue to pink, depending on soil pH.
This hydrangea typically grows 3 to 5 feet tall and wide, exhibiting a rounded, mounding habit. Its dark green, oval to elliptical leaves measure 4 to 8 inches long. As the season progresses, flowers can undergo subtle color changes, and foliage may develop burgundy shades in fall, adding seasonal interest.
Comprehensive Care for Shooting Star Hydrangea
Light and Location
‘Shooting Star’ Hydrangea thrives with a balance of sun and shade. The ideal location receives less intense morning sun, followed by filtered afternoon shade. While it can tolerate more sun if consistently moist, too much direct afternoon sun, especially in hotter climates, can lead to wilting or scorched leaves. Conversely, too much shade may result in fewer blooms.
Soil Requirements
This hydrangea prefers well-draining soil rich in organic matter. An acidic to slightly acidic pH level, ideally between 5.5 and 6.5, is suitable. Incorporating compost or other organic materials at planting time can improve drainage and fertility. If the soil is alkaline, amendments like peat moss or aluminum sulfate can help lower the pH.
Watering Needs
Consistent moisture is important for ‘Shooting Star’ Hydrangea, particularly during establishment and dry periods. The plant requires regular, deep watering to adequately hydrate the root zone, but it should not sit in soggy conditions. Water thoroughly until excess drains, or ensure consistent moisture without waterlogging. Allow the top half-inch of soil to dry out slightly before rewatering.
Fertilization
Fertilizing ‘Shooting Star’ Hydrangea supports healthy growth and abundant blooms. Apply a balanced, slow-release fertilizer, such as a 10-10-10 formula, in early spring when new growth begins. Some gardeners fertilize again in early May or late June. Avoid fertilizing in late summer or fall, as this can promote tender new growth vulnerable to winter damage.
Pruning for Health and Shape
‘Shooting Star’ Hydrangea generally blooms on old wood, with flower buds forming on stems from the previous year’s growth. Pruning should be minimal and performed immediately after flowering in late summer. Focus on removing dead, damaged, or weak stems, and thin out older growth to maintain the plant’s shape and encourage air circulation. Heavy pruning in late fall, winter, or early spring can remove flower buds and reduce the following season’s bloom.
Winter Protection
In colder climates, winter protection helps safeguard the ‘Shooting Star’ Hydrangea’s flower buds and roots. Apply a layer of organic mulch, such as leaves or wood chips, around the base of the plant out to the drip line to insulate roots from freezing temperatures. In areas where winter temperatures consistently dip below 20°F (USDA zones 6 and below), covering the plant with burlap or a protective cage filled with straw offers additional protection for canes and buds.
Addressing Common Challenges
When growing ‘Shooting Star’ Hydrangea, gardeners may encounter several issues, often linked to environmental factors or care practices.
Lack of Blooms
A lack of blooms can result from improper pruning, especially if done after flower buds have set on old wood. Winter damage to these buds from late frosts can also prevent flowering, even if the plant appears healthy. Covering the plant during unexpected cold snaps in spring offers some protection.
Yellowing Leaves (Chlorosis)
Yellowing leaves (chlorosis) frequently indicate a nutrient deficiency, most commonly iron, or issues with soil pH. If new leaves turn yellow but veins remain green, iron deficiency is likely, often due to alkaline soil preventing nutrient uptake. Adjusting soil pH with acidifying agents or using chelated iron can help. Overwatering, underwatering, or poor drainage that suffocates roots can also cause yellowing.
Wilting
Wilting in ‘Shooting Star’ Hydrangea often signals insufficient water, particularly during hot periods, as its large leaves lose moisture quickly. However, overwatering can also cause wilting by leading to root rot, which impairs the plant’s ability to absorb water. Consistent, deep watering and well-draining soil are important. Transplant shock, too much sun exposure, or over-fertilization can also contribute to wilting or weak, drooping stems.