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Chelonopsis yagiharana (Yagihara Chelonopsis)
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Chelonopsis yagiharana

Yagihara Chelonopsis

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At a Glance

HabitUpright
FoliageDeciduous
Height18-30 inches (45-75 cm)
Width12-18 inches (30-45 cm)
Maturity3 years

Growing Zones

USDA Hardiness Zones

5 - 8
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Overview

Chelonopsis yagiharana is an upright, clump-forming, herbaceous perennial reaching 18–30 inches (45–75 cm) tall with a spread of 12–18 inches (30–45 cm). Despite the shared common name 'turtlehead,' Chelonopsis is in the mint family (Lamiaceae) and is not closely related to the North American Chelone (Plantaginaceae)—a common point of confusion in horticultural references. The plant carries tubular, two-lipped, rosy-pink to mauve-pink flowers 1–1.5 inches (2.5–4 cm) long in axillary clusters along the upper stems from September through October. The flowers are more tubular and narrower than Chelone, with a less pronounced 'turtle head' shape. Leaves are opposite, ovate to lanceolate, 3–5 inches (8–13 cm) long, medium green, with serrate margins. Stems are square in cross-section (typical of Lamiaceae). Growth rate is moderate. The plant is rarely cultivated outside specialist collections and Japanese woodland gardens. It spreads slowly by short rhizomes, expanding 4–6 inches (10–15 cm) per season under suitable conditions. Requires shade and consistent moisture; heat above 90°F (32°C) and drought cause leaf scorch and bloom failure.

Native Range

Chelonopsis yagiharana is native to Japan (Honshu), where it is endemic to moist mountain forests and shaded streamsides in the Yagihara region and surrounding areas of central Honshu. It occurs at elevations from 1,500 to 4,500 feet (450–1,400 m).

Suggested Uses

Planted in woodland gardens, shade borders, and specialist collections at 12–18 inch (30–45 cm) spacing. The September–October bloom carries fall color into shaded settings where most fall-flowering perennials struggle for sufficient light. Functions in Japanese-style woodland gardens. Paired with ferns, Kirengeshoma, and shade-tolerant grasses, the rosy-pink flowers contrast with the surrounding green foliage in a late-season composition. Sunny borders, dry sites, and containers are unsuitable.

How to Identify

Separated from Chelone (true turtlehead) by placement in Lamiaceae (versus Plantaginaceae), the more tubular (versus strongly hooded) flower shape, and the axillary (versus dense terminal spike) flower arrangement. Separated from other Chelonopsis species by the specific flower size and Yagihara regional origin. Axillary clusters of tubular rosy-pink flowers on square stems with opposite, serrate leaves in a shade-loving, moisture-dependent plant identify this species.

Appearance

Size & Dimensions

Height1'6" - 2'6"
Width/Spread1' - 1'6"

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~5 weeks
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Tubular, two-lipped, rosy-pink to mauve-pink flowers 1–1.5 inches (2.5–4 cm) long open in axillary clusters along the upper stems from September through October. Bloom duration is 4–5 weeks. Pollinators include long-tongued bumblebees that can reach the deep tubular nectaries.

Detailed Descriptions

Flower Description

Rosy-pink to mauve-pink

Foliage Description

Medium green, ovate, serrate margins

Growing Conditions

Sun Requirements

Requires 1-4 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 6.5(Neutral)
357912
Soil Types
Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Plant in partial to full shade in moist, humus-rich, well-drained soil. Consistent moisture through the growing season is the single most limiting cultural requirement; drought stress causes leaf scorch and bloom failure. Heat above 90°F (32°C) damages foliage. Cool, sheltered locations matching the cool mountain forests of central Honshu suit the plant. No serious pest or disease problems. Rarely available in the nursery trade; specialist woodland plant nurseries and plant society sales are the primary sources.

Pruning

Cut all dead stems to the ground in late fall after frost or in early spring before new growth emerges. No pruning needed during the growing season. Clumps can be divided every 3–4 years in early spring to maintain vigor.

Pruning Schedule

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early spring

Maintenance Level

very low

⚠️ Toxicity Warning

Non-toxic