Minerva Althea Tree Form

Minerva Althea Tree Form brings a soft, sophisticated glow to any landscape. Her blooms are a luminous lavender with a bold ruby red eye, creating a gentle yet captivating contrast. Grafted into a tidy tree form, she reaches about 8 feet tall and 5 feet wide - perfect for anchoring a small bed, adding height to a border, or creating a floral focal point on the patio. 

• Deciduous tree
• Moderate growth rate
• Lavender flowers with a dramatic red center
• Blooms continuously from midsummer into fall
• Tree form makes it ideal for smaller landscapes or container growing

Plant in full sun for the best flower display. Hardy in USDA zones 5 through 9, and thrives in well-drained soil. Whether you’re building a landscape of color or just need a little drama in a neat, upright package - Minerva’s here to deliver with poise and petals.

The Minerva was one of the first major sterile Altheas released by the U.S. National Arboretum. They are triploids, meaning they are genetically incapable of producing seeds.

Minerva Althea Tree Form is reliably low-maintenance once established. Its defined trunk and balanced canopy make seasonal care simple and structured. Here’s all it needs to thrive:

• Watering: Water deeply during the first growing season to establish a strong, well-anchored root system. After establishment, it tolerates moderate dry conditions but benefits from supplemental irrigation during extended summer heat to maintain steady flowering and foliage quality.
• Pruning: Prune in late winter or very early spring before new growth begins. Remove any shoots along the trunk and selectively thin the canopy to preserve airflow and balanced structure, as blooms form on current-season growth.
• Fertilizing: Apply a balanced, slow-release fertilizer in early spring as buds begin to swell. Avoid excessive nitrogen, which may encourage dense foliage at the expense of flower production.
• Mulching: Maintain a 2-3 inch layer of mulch around the root zone to conserve moisture and moderate soil temperature. Keep mulch several inches away from the trunk to prevent bark moisture issues.
• Winter Care: Established tree-form plants are reliably hardy and typically require minimal protection. Young trunks may benefit from protective wrapping during their first few winters in colder climates to reduce temperature-related bark stress.

Minerva Althea Tree Form is generally durable, though occasional pests or environmental stresses may arise. Early monitoring allows for straightforward correction:

• Japanese Beetles: Leaves may show skeletonized feeding damage during midsummer. Hand removal or traps placed away from the tree help minimize ongoing defoliation.
• Leaf Spot: Small dark or brown lesions may appear during prolonged humid weather. Removing affected leaves and improving canopy airflow reduces spread.
• Aphids: New shoots may curl slightly and develop sticky residue from feeding insects. A firm spray of water or insecticidal soap controls infestations effectively.
• Root Stress from Compaction: Slowed growth and reduced vigor may occur in tightly compacted soils. Loosening surrounding soil and maintaining proper drainage supports healthier root development.
• Trunk Cracking: Young bark may split during sudden winter temperature fluctuations. Temporary trunk wrapping during early years helps prevent damage.