How to Grow Water Iris Weymouth Blue
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Water Iris Weymouth Blue
Iris laevigata 'Weymouth Blue'
flowerWeymouth Blue is a stunning Japanese water iris cultivar with deep blue flowers and elegant sword-like foliage. This deciduous perennial thrives in wet environments, ideal for water gardens, pond edges, and boggy areas. It produces large, ruffled blooms on tall stems above attractive green foliage.
When should you plant Water Iris Weymouth Blue in your zone?
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Example Water Iris Weymouth Blue timeline · Pittsburgh, PA (Zone 6b)
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Plant Water Iris Weymouth Blue
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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First Water Iris Weymouth Blue blooms
Mid-to-late summerBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Water Iris Weymouth Blue dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 4-9, with best performance in zones 5-8
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Get my Water Iris Weymouth Blue timeline →Growth Stages
Dormancy
December-FebruaryPlant is dormant underground during winter months. Foliage dies back completely.
No active care needed; do not remove dead foliage as it protects the rhizome. Leave plants undisturbed.
Spring Growth
March-AprilNew sword-like green foliage emerges from the rhizome as soil warms in spring.
Ensure consistent moisture and shallow water levels. Remove any winter debris. Begin monthly feeding with aquatic plant fertilizer.
Vegetative Development
May-MayFoliage grows taller and fuller; plant develops a robust clump of green leaves.
Maintain water level and consistent moisture. Support stems if needed in windy locations. Continue light fertilizing.
Flowering
June-JulyTall stems (24-36 inches) emerge bearing deep blue, ruffled flowers with yellow signals on the falls.
Deadhead spent blooms to encourage additional flushes. Ensure adequate sunlight and water. Do not allow soil to dry out.
Post-Bloom & Maturation
August-OctoberFlowers fade; foliage continues to grow and photosynthesize. Seed pods may form if flowers are not deadheaded.
Continue regular watering and fertilizing through summer. Leave foliage intact for nutrient storage in the rhizome.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Remove and destroy affected foliage. Keep area clean. Divide plants regularly to inspect rhizomes for larvae.
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Spray with water stream or insecticidal soap. Encourage natural predators.
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Hand-pick pests. Use copper barriers or iron phosphate baits around planting area.
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Remove infected foliage. Improve air circulation. Avoid overhead watering.
Uses
Not for consumption
CulinaryWater iris is ornamental only and should not be eaten or used in beverages. [source]
Cut flower arrangements
HouseholdThe striking deep blue blooms make elegant fresh flower arrangements for vases and floral displays. Stems can last several days in water when properly cut and conditioned. [source]
Pressed flowers
CraftThe petals and flowers can be pressed and dried for use in crafts, scrapbooking, and botanical art projects. [source]
Pollinator support
WildlifeIris flowers attract bees and other pollinators, providing important nectar sources in early summer. The dense foliage also offers shelter for aquatic insects. [source]
Water garden focal point
HouseholdThe elegant form and striking blue color make this iris a stunning focal point for ponds, water gardens, and bog gardens, providing vertical interest and structure. [source]
Harvest Tips
Not harvested for food or commercial use. Cut flowers for arrangements by cutting stems near the base early in the morning. Leave at least 2-3 leaves on the plant for continued growth. Flowers last 1-2 days per bloom, with multiple blooms per stem.
Fun Facts
- 🌱 Japanese water irises (Iris laevigata) have been cultivated in Japan for over 500 years and are celebrated in traditional gardens. 'Weymouth Blue' is a classic cultivar bred specifically for the ornamental pond trade.
- 🌱 Unlike bearded irises, water irises thrive in saturated soil and can actually be planted directly in shallow water, making them extremely versatile for wetland gardens.
- 🌱 The distinctive blue color of 'Weymouth Blue' flowers contains delphinidin anthocyanins, the same pigments that give blueberries and blue corn their color.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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