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How to Grow Double-Flowered Nasturtium Hermine Grashoff

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Double-Flowered Nasturtium Hermine Grashoff

Tropaeolum majus 'Hermine Grashoff'

flower

Hermine Grashoff is a stunning double-flowered nasturtium cultivar featuring fully double, ruffled blooms in deep crimson-red with dark veining. This tender perennial is typically grown as an annual and produces semi-trailing growth with lush green foliage and long flowering season. The unique pompon-like flowers make it a standout ornamental for containers, hanging baskets, and garden beds.

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Example Double-Flowered Nasturtium Hermine Grashoff timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Double-Flowered Nasturtium Hermine Grashoff

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Double-Flowered Nasturtium Hermine Grashoff blooms

    Around Jun 6

    ≈ 50 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Double-Flowered Nasturtium Hermine Grashoff dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun to part shade; 5-6 hours of sunlight daily for best flowering
💧
Water: Moderate, consistent moisture without waterlogging. Allow soil to dry slightly between waterings. Reduce watering in cooler months if overwintering.
📏
Spacing: 12 inches
📅
Days to maturity: 50-70 days to first flowers
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Planting depth: 0.5-0.75 inches for seeds; plant transplants at soil level

Soil

Type: Well-draining, moderately fertile loamy soil
pH: 6.0-7.0
Amendments:
Compost Perlite or sand for drainage Avoid excessive nitrogen

Growing Zones

Find your zone →

Zones 10-11 as a perennial; grown as annual in zones 3-9

10a 10b 11a 11b

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Growth Stages

1

Seedling

2-3 weeks

Cotyledons emerge with characteristic round seed leaves; true leaves develop within 1-2 weeks

Keep soil consistently moist but not waterlogged. Provide bright light. Thin seedlings to proper spacing if direct sowing.

2

Vegetative Growth

3-4 weeks

Plant develops multiple stems with rounded, attractive foliage; no flowers yet. Growth is bushy and spreading.

Pinch back stem tips when plant reaches 4-6 inches to encourage bushier growth and more flowering branches. Water regularly. Avoid excessive nitrogen fertilizer.

3

Budding

1-2 weeks

Flower buds form at leaf axils; distinctive double-flowered form begins to develop in compact clusters

Continue regular watering and light feeding with balanced or low-nitrogen fertilizer. Provide adequate air circulation to prevent fungal issues.

4

Flowering

8-12 weeks (or longer with proper care)

Double, ruffled crimson-red flowers with dark veining open fully; continuous blooming through season. Flowers are 1.5-2 inches across.

Deadhead spent flowers regularly to encourage continuous blooming. Maintain consistent moisture. Feed every 2-3 weeks with balanced fertilizer.

5

Decline & Overwintering

Variable, season-end

In frost-prone areas, plants yellow and decline with frost. In zones 10-11, plants may persist and regrow from base.

In zones 3-9, allow first frost to end season or pull plants. In zones 10-11, cut back by half and reduce watering to encourage overwintering.

Companion Planting

Plan your garden →

Plant with:

Borage Marigold Cabbage Cucumber Petunia Zinnia Verbena

Avoid planting near:

Fennel Dill Potato

Common Pests

  • Spray with strong water stream; use neem oil or insecticidal soap if severe. Encourage natural predators like ladybugs.

  • Use yellow sticky traps; spray undersides of leaves with neem oil or insecticidal soap weekly until controlled.

  • Increase humidity; spray leaves with water frequently. Use neem oil or miticide if infestation is severe.

  • Hand-pick if few; use Bt (Bacillus thuringiensis) spray for larger infestations. Remove affected leaves.

  • and

    Hand-pick in early morning; create barriers with crushed eggshells or diatomaceous earth. Beer traps attract and drown them.

Uses

🍳

Edible Flowers for Garnish

Culinary

The double flowers of Hermine Grashoff are edible and make striking garnishes for salads and desserts. They add a peppery, slightly peppery flavor and vibrant color to culinary presentations. [source]

🏠

Cut Flower Arrangements

Household

The long-lasting, unique double blooms make excellent cut flowers for bouquets and floral arrangements. Their unusual pompon-like form adds textural interest to floral designs. [source]

💊

Traditional Herbal Uses

Medicinal

Nasturtium flowers and leaves have been used in traditional medicine for immune support and skin health. The plant contains sulfur compounds with antimicrobial properties. [source]

🎨

Ornamental Container & Basket Plant

Craft

The semi-trailing habit and spectacular double flowers make this cultivar ideal for hanging baskets, window boxes, and decorative containers on patios and balconies. [source]

🦋

Pollinator Attraction

Wildlife

Nasturtiums attract hoverflies, bees, and beneficial insects to the garden. While the double-flowered form produces less nectar than singles, it still provides visual interest and some nectar. [source]

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

Harvest Tips

Nasturtiums are grown for ornamental flowers rather than harvest. Deadhead spent double flowers regularly by pinching off the flower base just below the seed pod to encourage continuous blooming throughout the season. In zones where they persist, cut back the entire plant by half in late fall to prepare for overwintering indoors or in a greenhouse.

Fun Facts

  • 🌱 Hermine Grashoff is a rare, double-flowered selection that was nearly lost to cultivation but has been preserved by specialty nurseries and heirloom seed savers. The doubled petals occur naturally, creating a unique pompon effect.
  • 🌱 Nasturtiums were treasured by Victorian gardeners and appear in period paintings and botanical illustrations. The double forms were particularly prized for their unusual appearance.
  • 🌱 The plant's seed pods, called 'capers,' can be pickled and used as a peppery condiment similar to true capers, though this is rarely done with ornamental cultivars like Hermine Grashoff.

Gardening Terms

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

Annual Cultivar Deadhead Direct Sow Full Sun Perennial Pinch Back True Leaves
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