How to Grow Rehmannia

Wikimedia Commons

Rehmannia

Rehmannia glutinosa

herb

Rehmannia is a traditional Chinese medicinal herb with distinctive tubular, purple-pink flowers and a fleshy root system that is highly valued in herbal medicine. The plant grows as a low herbaceous perennial, typically reaching 12-24 inches tall with soft, hairy foliage. It has been cultivated for over 2,000 years in traditional Chinese medicine for its adaptogenic and nourishing properties.

When should you plant Rehmannia in your zone?

Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.

Get my Rehmannia timeline →

Example Rehmannia timeline · Pittsburgh, PA (Zone 6b)

Plant Rehmannia
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Rehmannia
Late summer into fall

Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Rehmannia dates for your own zip code.

Growing Conditions

☀️

Sun: Partial shade to partial sun, 4-6 hours of indirect sunlight daily

💧

Water: Moderate moisture; keep soil consistently moist but not waterlogged. Water deeply during growing season, reduce in winter dormancy. Avoid overhead watering to prevent fungal issues.

📏

Spacing: 12-18 inches

📅

Days to maturity: 180-240 days to harvest roots (typically 1-2 years for optimal root development)

🌱

Planting depth: Surface sow seeds lightly pressing into soil; transplant seedlings when 2-3 inches tall

Soil

Type: Well-draining sandy loam soil with organic matter

pH: 6.0-7.0

Amendments:

Compost aged manure peat moss or coco coir perlite for drainage

Growing Zones

Find your zone →

Thrives in zones 6-9, preferring temperate climates with moderate winters

6a 6b 7a 7b 8a 8b 9a 9b

Get my Rehmannia timeline →

Growth Stages

Seed Germination

2-3 weeks

Tiny seedlings emerge with first true leaves appearing within 2-3 weeks; very delicate with minimal root development.

Maintain consistent moisture and warmth (65-75°F). Provide bright indirect light. Keep soil surface from drying out; use misting if needed.

Seedling to Transplant

4-6 weeks

Young plants develop 4-6 true leaves and establish a stronger root system; growth remains relatively slow.

Thin seedlings to proper spacing. Begin light feeding with dilute liquid fertilizer. Gradually acclimate to stronger light and air movement.

Vegetative Growth

8-12 weeks

Plant produces soft, hairy foliage with multiple stems branching out; leaves are deeply lobed and grow in basal rosette patterns. Root expansion accelerates.

Maintain consistent moisture and moderate nutrients. Avoid excessive nitrogen which encourages leaf growth at root expense. Provide afternoon shade in hot climates.

Flowering

4-6 weeks

Distinctive purple-pink, tubular flowers with hairy calyces appear on spikes; flowers are quite ornamental and attract pollinators.

Continue regular watering and moderate feeding. Deadhead spent flowers to encourage continued blooming if harvesting leaves; allow some to set seed for propagation.

Root Development & Dormancy

8-12 weeks

Above-ground foliage begins declining; plant energy redirects to fleshy root thickening and maturation. Tuber-like roots become full and starchy.

Reduce watering as plant naturally enters dormancy. Stop fertilizing. Do not disturb roots. If overwintering, provide cool conditions (50-60°F) with minimal water.

Companion Planting

Plan your garden →

Plant with:

Ginseng Goji berry Astragalus Codonopsis Peony Licorice

Avoid planting near:

Heavy feeders like corn or wheat plants requiring very dry conditions aggressive spreading herbs like mint

Common Pests

Ensure good air circulation, avoid overhead watering, apply sulfur dust or neem oil if needed
Improve drainage, avoid overwatering, remove affected plants, use well-draining soil amendments
and
Hand-pick, use copper barriers, apply diatomaceous earth, encourage natural predators
Spray with water, apply insecticidal soap, use neem oil, attract beneficial insects
Increase humidity, spray with water, apply neem oil, maintain good air circulation

Uses

💊

Immune & Energy Support

Medicinal

In traditional Chinese medicine, Rehmannia root is considered a yin-nourishing tonic herb that supports immune function, energy levels, and overall vitality. It is commonly used as a primary ingredient in herbal formulations for fatigue and weakness. [source]

💊

Kidney & Blood Tonification

Medicinal

Rehmannia is traditionally used to support kidney health and nourish blood, with applications in traditional formulas aimed at addressing anemia-like conditions and supporting reproductive health. [source]

💊

Inflammatory & Heat-Clearing Actions

Medicinal

The herb contains compounds that support the body's natural inflammatory response and is traditionally used in heat-clearing formulations, particularly for supporting skin health and addressing excess heat conditions. [source]

🍳

Herbal Cooking & Tonic Soups

Culinary

In Asian cuisine, particularly Chinese cooking, Rehmannia roots are used in slow-cooked soups and broths called 'tonic soups' or 'medicinal soups' that blend nutrition with traditional health benefits. [source]

🏠

Herbal Extract & Supplement Production

Household

Dried Rehmannia roots are processed into concentrated extracts, powders, and supplements for use in traditional herbal formulations and modern herbal practice. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Harvest roots in autumn (fall) after 1-2 years of growth when foliage dies back naturally. Carefully dig to avoid damaging the fleshy roots. Clean roots gently and dry slowly in warm, well-ventilated area (2-3 weeks). Leave small roots in soil for regrowth. For fresh leaf harvesting, pinch young growth tips anytime during the growing season.

Fun Facts

🌱 Rehmannia has been documented in Chinese herbal medicine texts for over 2,000 years and is one of the 50 fundamental herbs in traditional Chinese medicine (TCM).
🌱 The plant has two main processed forms in TCM—'raw rehmannia' (sheng di huang) used for cooling properties and 'prepared rehmannia' (shu di huang) created by processing with wine and used for warming, nourishing effects.
🌱 Rehmannia's beautiful tubular flowers are pollinated by bumblebees and attract them readily, making it a good addition to medicinal gardens that support pollinator populations.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Deadhead Partial Shade Perennial True Leaves

Shop Rehmannia plants and related plants at Plant Addicts →

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized Rehmannia planting timeline

Tell us your zip code and we'll calculate exactly when to start Rehmannia seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.

Get my Rehmannia timeline →