Nepeta (Nepeta 'Six Hills Giant')

Overview

Nepeta ‘Six Hills Giant’ is a vigorous and highly valued herbaceous perennial celebrated for its substantial clump-forming habit and extended period of bloom. This specific cultivar provides masses of fragrant, lavender-blue flowers from early summer well into the fall, making it an essential component for long-lasting color in the garden. As one of the most popular ornamental members of the Nepeta genus, it combines rugged durability with undeniable visual appeal.

This variety of Nepeta thrives when given plenty of sunlight, though it can tolerate light afternoon shade, especially in hotter climates. A key benefit is its exceptional resilience; it handles dry soils and periods of drought with ease once established. Gardeners appreciate the low maintenance required by Nepeta ‘Six Hills Giant’, as it largely takes care of itself while repelling common garden pests.

The aromatic, gray-green foliage of Nepeta ‘Six Hills Giant’ offers continuous texture even when not in full bloom. While the true catnip, Nepeta cataria, is the main attractor for house cats, this hybrid remains a fantastic choice for mass plantings, borders, and creating informal cottage garden settings where tough, reliable performance is needed.

Fast Facts

• Plant Family: Lamiaceae
• Plant Type: Herbaceous perennial
• Hardiness Zones: USDA Zones 4-7
• Size at Maturity:
  • Height: 2-3 ft
  • Spread: 2-4 ft
• Bloom Time: June to September
• Bloom Description: Blue
• Sun Exposure: Full sun to part shade
• Water Needs: Dry to medium
• Maintenance Level: Low

How to Grow

Nepeta performs best when planted in well-drained soil, whether that soil is average or slightly dry. Full sun exposure is ideal, particularly in cooler northern regions, to ensure the densest growth and most prolific flowering. If you are situated in areas prone to high heat and humidity, planting where the plant receives some light protection from the intense afternoon sun will prevent stress.

Water requirements for Nepeta ‘Six Hills Giant’ are minimal once established; it thrives in dry to medium moisture conditions and is highly drought tolerant. Overly moist soil is its main enemy, potentially leading to issues like crown rot. Generally, fertilizing is unnecessary as this plant is not demanding, though rich soil can sometimes result in floppier growth that requires structural support.

Maintenance is simple. To encourage repeat blooming throughout the season, shear the spent flower spikes after the initial heavy flush of flowers fades. Taller clumps may benefit from being cut back by about one-third mid-season if they begin to slump. Propagation is easily accomplished through plant division.

Landscape Uses

Nepeta ‘Six Hills Giant’ excels in positions where its graceful, slightly arching habit can spill softly over edges. It is particularly effective when used in mass plantings, creating impressive drifts of soothing blue color that lead the eye, or as an informal edging along winding pathways. Its drought and poor soil tolerance also make it an excellent, reliable choice for difficult, dry areas of the landscape.

This substantial perennial pairs beautifully with sun-loving perennials that share similar moderate water needs. Consider planting it alongside plants with contrasting foliage textures, such as ornamental grasses or silver-leaved Artemisia. It serves well in cottage gardens due to its relaxed appearance or can provide a softening contrast against more formal structural plantings. Containers are also viable, provided excellent drainage is assured.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Nepeta is a genus which contains about 250 species of perennials plus a few annuals, all of which are native to Europe, Asia, and Africa. Plants are usually aromatic, and mostly feature sharply toothed or deeply cut leaves and whorls of blue, lavender or white flowers in elongated spikes or panicles. Genus name comes from the Latin name for certain aromatic plants that included catmint. It may honor the city of Nepete (known as Nepi today) located north of Rome in Etruria which was the ancient country located between the Arno and Tiber Rivers and was recognized, prior to the rise of Rome, as the center of the Etruscan civilization. ‘Six Hills Giant’, sometimes commonly called catmint, is a vigorous sterile hybrid which typically grows in a clump to 3’ tall and slightly wider. It is one of the most popular ornamental plants in the genus. It is often classified as a cultivar of N. X faassenii, but is also sometimes classified under the horticultural name of N. Gigantean. Parents of this hybrid are unknown. Showy terminal spikes (to 9-12” long) of fragrant two-lipped lavender-blue flowers bloom primarily in summer (June-July) but sometimes with sporadic continued bloom extending throughout summer into early fall. Narrow ovate, toothed, hairy, light gray-green leaves (1.5” long) are aromatic when crushed or bruised. Although Nepeta cataria is the true catnip loved by house cats, the leaves of this hybrid, although somewhat less enticing, are also attractive to cats.

Tolerances

• Rabbit
• Deer
• Drought
• Dry Soil
• Shallow-Rocky Soil
• Air Pollution

Potential Problems

Nepeta ‘Six Hills Giant’ is generally quite resistant to serious insect or disease issues, which contributes significantly to its low maintenance rating. The primary danger arises from improper siting; crown rot is a distinct possibility if the plant is situated in heavy, poorly drained soil that retains too much moisture. While somewhat deer and rabbit resistant, it is important to maintain vigilance against powdery mildew, especially in high-humidity settings or when air circulation is poor. Ensure adequate spacing during planting to mitigate mold and mildew risks.

Frequently Asked Questions

What hardiness zones is Nepeta ‘Six Hills Giant’ suitable for?

This vigorous perennial is reliably hardy across USDA Zones 4 through 7.

How large does Nepeta grow?

Nepeta ‘Six Hills Giant’ typically matures to a height between 2 and 3 feet tall, spreading from 2 to 4 feet wide, forming a substantial clump.

When does Nepeta bloom?

The primary bloom time for Nepeta ‘Six Hills Giant’ runs from June through September, putting on a reliable display of blue flowers.

What sun exposure does Nepeta need?

For optimal performance and strongest stems, plant this variety in full sun, though it will tolerate areas receiving light shade.

Conclusion

The enduring popularity of Nepeta ‘Six Hills Giant’ stems from its exceptional drought tolerance, low maintenance needs, and reliable season-long blue blooms. This robust Nepeta hybrid is a cornerstone for sustainable, colorful garden design. Check your local hardiness zone and plan to plant this cultivar in the spring or fall in a location with excellent drainage.

Companion Planting

Choosing strong companions enhances the landscape appeal of Nepeta ‘Six Hills Giant’ while respecting its cultural needs. Because Nepeta prefers well-drained, dry-to-medium conditions, pair it with other sun-loving, drought-tolerant perennials such as ornamental grasses like Calamagrostis, or sturdy companions like Salvia (Salvia nemorosa varieties) and Yarrow (Achillea). These combinations create beautiful textural and color contrasts without one plant outcompeting the other for water or nutrients. If you are seeking a silvery color scheme, contrast the blue-purple flowers of the Nepeta with silvery foliage plants, which also tend to prefer drier conditions and full sun.

Propagation Tips

Propagating Nepeta ‘Six Hills Giant’ is a straightforward process best accomplished via division, which is an excellent way to refresh established clumps every few years. Ideally, divide the clumps in early spring before new growth vigorously emerges, or in the early fall after blooming has finished. Dig up the entire clump and gently use a sharp spade or knife to separate it into smaller sections, ensuring each new division has a healthy root system attached. Replant these divisions immediately into prepared soil at the same depth they were growing previously. This method ensures the new plant retains the desirable characteristics of the parent ‘Six Hills Giant’ cultivar.