The ‘Althea Blueberry Smoothie’ is a specific cultivar of Hibiscus syriacus, commonly known as Rose of Sharon. This deciduous shrub is valued for its attractive and prolonged flowering period, making it a popular choice for various garden designs. Its ability to thrive in diverse conditions contributes to its widespread appeal as an ornamental plant.
Distinctive Features of ‘Blueberry Smoothie’
The ‘Blueberry Smoothie’ cultivar stands out with its unique floral characteristics. It produces beautiful double blooms that are a distinctive bluish-purple color, appearing from mid-summer into fall. These large, showy flowers resemble peonies or carnations, providing a tropical appearance to temperate gardens. An advantageous trait of this cultivar is its near-seedless nature, which helps prevent unwanted self-seeding and reduces its potential for invasiveness in the landscape.
This shrub grows with an upright, multi-stemmed habit, reaching a mature height of approximately 6 to 8 feet and spreading about 3 to 4 feet wide. Its green, serrated leaves provide a consistent backdrop throughout the growing season, though they do not offer significant fall color. ‘Blueberry Smoothie’ is a hardy plant, suited for USDA Hardiness Zones 5 through 9, tolerating heat, humidity, drought, and urban pollution.
Planting and Establishment
Selecting an appropriate planting site is important for ‘Althea Blueberry Smoothie’. This shrub thrives in locations that receive full sun, meaning at least six hours of direct sunlight daily, though it can tolerate some partial shade. Adequate sunlight encourages more prolific blooming.
The plant adapts to various soil types, but it prefers well-draining soil with a slightly acidic to neutral pH. When planting, dig a hole at least twice as wide as the root ball and deep enough so the top of the root ball is level with or slightly above the surrounding soil. After placing the plant, backfill the hole with soil, gently tamping to remove air pockets, and water thoroughly to settle the soil around the roots. Applying a layer of mulch around the base after planting helps retain moisture and suppress weeds.
Ongoing Care and Maintenance
Consistent watering benefits ‘Althea Blueberry Smoothie’, especially during establishment and prolonged dry spells. Water deeply to encourage a robust root system. While established plants exhibit good drought tolerance, supplemental water during hot, dry periods supports continued vigor and flowering.
Fertilization is not often required for established Rose of Sharon shrubs unless soil quality is poor. If needed, a slow-release, balanced fertilizer (such as a 10-10-10 or 14-14-14 formula) can be applied in early spring. For new plantings, a root-stimulating fertilizer without high nitrogen levels is used, or nutrient-rich organic matter can be mixed into the planting hole. Over-fertilization should be avoided, as it can lead to excessive foliage growth at the expense of blooms or even cause damage to the plant.
Pruning ‘Blueberry Smoothie’ is best performed in late winter or early spring before new growth emerges. This timing helps avoid removing flower buds, as the plant blooms on new wood. Pruning involves removing any dead, damaged, or diseased branches, as well as shaping the shrub to maintain its desired size and form. Up to one-third of the plant can be removed at a time to promote healthy growth and encourage a more abundant display of flowers.
Common Growing Considerations
‘Althea Blueberry Smoothie’ is a resilient shrub, but it can encounter common garden issues. Aphids are small, soft-bodied insects that may cluster on new growth and the undersides of leaves, feeding on plant sap. Signs of aphid infestation include curled or yellowing leaves and a sticky residue known as honeydew. A strong spray of water often dislodges aphids, or insecticidal soap can be used for more persistent issues.
Spider mites are another potential pest, especially in hot, dry conditions, causing yellowing or stippling on leaves and sometimes fine webbing. Consistent moisture and regular misting deters them. Japanese beetles may also feed on the foliage. Monitoring for these pests and addressing them promptly helps maintain the plant’s health. Ensuring proper planting conditions and consistent, appropriate care helps the ‘Blueberry Smoothie’ thrive and resist environmental stresses.