How to Grow Catmint 'Six Hills Giant'

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Catmint 'Six Hills Giant'

Nepeta × faassenii 'Six Hills Giant'

flower

A vigorous, semi-evergreen perennial hybrid catmint that produces abundant lavender-blue flowers on tall, airy stems. 'Six Hills Giant' is a popular cultivar known for its exceptional size and prolific blooming habit, reaching 2-3 feet tall. It attracts pollinators while adding soft color and texture to gardens throughout the growing season.

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Example Catmint 'Six Hills Giant' timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Catmint 'Six Hills Giant'

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Catmint 'Six Hills Giant' blooms

    Around Apr 25

    ≈ 8 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Catmint 'Six Hills Giant' dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily; tolerates light afternoon shade in hot climates
💧
Water: Low to moderate water needs once established; prefers dry to average moisture; water weekly during establishment, then reduce frequency. Very drought-tolerant; overwatering causes decline and mildew.
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Spacing: 18-24 inches
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Days to maturity: Blooms begin 8-10 weeks from transplant; full mature size by second season
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Planting depth: Transplants at soil surface or slightly shallower; seeds barely covered (1/8 inch)

Soil

Type: Well-draining loamy soil; tolerates poor, rocky, or sandy soil
pH: 6.5-7.5
Amendments:
Perlite or coarse sand for drainage Gravel in heavy clay soils Minimal compost (avoid over-enrichment)

Growing Zones

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Thrives in zones 3-9, best performance in zones 4-8

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b

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Growth Stages

1

Seedling/Transplant

2-3 weeks

Small rosette of aromatic, soft gray-green foliage with delicate, lobed leaves

Keep soil lightly moist until roots establish (2-3 weeks); avoid waterlogging. Provide bright light. Harden off transplants gradually before planting outdoors.

2

Vegetative Growth

4-6 weeks

Rapid stem elongation and leaf expansion; plant becomes bushy and mounding with increasingly abundant foliage

Water weekly if rain is absent. Pinch back stems in spring to encourage bushier, more compact growth. No fertilizer needed; too much nitrogen reduces flowering and hardiness.

3

Early Flowering

2-3 weeks

First flower spikes emerge at stem tips; delicate, small tubular lavender-blue flowers arranged in loose, airy clusters

Begin regular deadheading to extend bloom season. Cut faded flower clusters just below the flower head to encourage new branching and continuous blooming.

4

Peak Bloom

4-8 weeks (often June-July, may repeat in fall if deadheaded and watered in late summer)

Dense cover of lavender-blue flowers on tall, graceful stems; plant becomes a cloud of color and attracts numerous bees and butterflies

Continue deadheading spent flowers every 7-10 days. Water only during drought. Reduce or stop watering in late summer to encourage flower production over foliage.

5

Post-Flowering/Dormancy

Fall through early spring

Flowers fade; foliage becomes silvery-gray and semi-evergreen; stems may remain attractive through winter

Cut back plants to 6-12 inches in late fall or early spring to remove dead or damaged wood and rejuvenate growth. Leave some stems standing for winter interest if desired.

Companion Planting

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Plant with:

Russian Sage (Perovskia) Salvia Coreopsis Black-eyed Susan (Rudbeckia) Daylily (Hemerocallis) Lavender (Lavandula) Ornamental grasses (Festuca, Stipa) Sedums Blanket Flower (Gaillardia) Yarrow (Achillea)

Avoid planting near:

Water-loving plants (Hostas, Astilbe, Ligularia) Plants requiring consistently moist soil Aggressive self-seeders in small spaces (though catmint itself can self-seed)

Common Pests

  • Spray with water to dislodge; insecticidal soap if severe. Ensure good air circulation. Avoid overhead watering.

  • Improve air circulation by spacing plants adequately and pruning lower foliage. Avoid overhead watering and excess humidity. Spray with sulfur or fungicide if necessary; remove and destroy infected leaves.

  • Spray with water; use insecticidal soap or neem oil for heavy infestations. Encourage natural predators like ladybugs and lacewings.

  • Yellow sticky traps; spray with insecticidal soap or horticultural oil. Improve air circulation.

Uses

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Herbal Tea & Flavor

Culinary

Catmint leaves and flowers can be dried and brewed into a soothing herbal tea with a mild, pleasant minty flavor and calming aromatic properties. The tea has traditionally been used to support relaxation and digestive comfort. [source]

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Traditional Herbal Remedy

Medicinal

Catmint has been used in traditional herbalism to support nervous system relaxation, healthy digestion, and emotional balance. Its mild sedative and antispasmodic properties make it a gentle herb for wellness routines. [source]

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Pollinator Magnet

Wildlife

The abundant flowers are a powerhouse for bees, butterflies, and other pollinators throughout the growing season, supporting garden biodiversity and enhancing fruit and vegetable set in nearby plants. [source]

🏠

Cut & Dried Flowers

Household

Both fresh and dried catmint flowers are attractive in bouquets and floral arrangements, adding airy texture and soft color. Dried flowers retain their fragrance and can be used in potpourri or dried arrangements. [source]

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Aromatic Crafts & Sachets

Craft

Dried catmint flowers and foliage can be used to make fragrant sachets, pot-pourri, herbal sleep pillows, and craft projects. The pleasant minty aroma lasts well when dried. [source]

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

Harvest Tips

Catmint is not typically harvested for food, but flowers can be cut for fresh arrangements throughout the blooming season. Cut stems in early morning after dew dries, just below a flower cluster. For drying (culinary or craft use), harvest just as flowers open, tie in bundles, and dry in a cool, airy location. Deadheading (removing spent flowers) extends the bloom season and maintains plant vigor; cut back to the nearest leaf node.

Fun Facts

  • 🌱 'Six Hills Giant' was developed in 1941 by Ernest Ladhams at the Six Hills Nursery in Stevenage, England, making it one of the classic catmint cultivars with over 80 years of garden proven performance.
  • 🌱 Catmint is called 'Nepeta' in its genus name, derived from Nepete, an ancient town in Egypt where catmint was historically cultivated, and it is closely related to catnip but less potent in attracting cats.
  • 🌱 The silvery-gray, finely textured foliage contains aromatic volatile oils that create the plant's characteristic minty fragrance and contribute to its pest-repellent and medicinal properties.

Gardening Terms

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