
Big Blue sea holly’s spiky features — sharply pointed leaves, bracts and inflorescences — give it an otherworldly feel, but this fascinating perennial even works in traditional garden settings. It has a dip-dyed appearance, as the upper flowers, stems and leaves are deep blue-violet, fading into silvery blue-green, grounded with deep blue-green basal foliage.
The thistle-like, violet-blue flowers bloom from June through August. In the fall and winter, flowers hold their form as a dried seed head. Flowers also attract a variety of bees, butterflies and other pollinators. The plants grow up to 2½ feet tall and feature strong stems.
Both blooming and dried flower heads are ideal as cut flowers. Big Blue sea holly is a drought tolerant plant that prefers well-drained, poor soils. It’s hardy in USDA Zones 5-9.

Latest from Produce Grower
- Fresh Express releases four new Chopped Salad Kits
- Orbia Netafim releases AI-powered Dosing 5G product range for precision fertigation
- Village Fresh Greenhouse Grown appoints Helen Aquino vice president of innovation
- Resource Innovation Institute and North Dakota State University explore co-location of data center and greenhouses
- When CapEx kills the farm
- Rethinking competition
- The National Association of State Departments of Agriculture sets 2026 federal policy focus
- 3 takeaways from Indoor Ag-Con’s ‘The State of CEA Finance’ keynote panel