These Perennials Provide Tall Flower Spires for Cool-Climate Gardens
Make a statement with Delphinium, prized for its towering spires of blue, purple, or white blooms. These vertical stars love cooler climates, thrive in well-drained, fertile soil, and bring classic cottage-garden drama to borders, cutting beds, and backdrop plantings.
Why Iowa Gardeners Choose Delphinium
- Striking vertical bloom spikes from early to midsummer
- Pollinator friendly—a magnet for bees and butterflies
- Often deer resistant; excellent cut flowers
- Reblooms in cool regions after a timely cutback
Planting & Spacing Instructions for Delphinium
- Best time to plant: Spring or fall
- Soil: Rich, well-drained soil; mix in compost for fertility and drainage
- Light: Full sun in cool summers; provide afternoon shade where summers run hot
- Spacing/size: Space 18–24″ apart; many varieties reach 3–6 ft tall
- Hardiness: Typically USDA Zones 3–7 (heat-sensitive in warmer zones)
Delphinium Care Made Simple
- Water: Keep evenly moist—never soggy. Mulch 2–3″ to cool roots
- Feeding: Heavy feeders—apply a balanced, slow-release fertilizer in spring; side-dress after first bloom.
- Staking: Install stakes or supports early; tall stems catch wind
- Grooming: Deadhead and cut back after first flush to encourage a late-season encore
- Health: Ensure airflow to limit mildew; watch for slugs/snails on young shoots
These Plants Partner Well with Delphinium
Pair Delphinium with roses, peonies, foxglove, allium, salvia, nepeta, yarrow, and ornamental grasses for layered color, texture, and height.
Shop for Delphinium and Other Perennials at Holub Greenhouses in Ames
Discover locally selected Delphiniums sized for borders and cutting gardens. Holub Greenhouses’ perennial plant experts can help match color, height, and bloom window to your site—so your summer display stands tall, vibrant, and elegant.