Catmint 'Six Hills Giant'

Sun

Full sun; tolerates light shade but flowers less and may flop.

Water

Water regularly during establishment; once established, water during prolonged drought. Avoid persistently wet soil.

Soil

Well-drained soil, including sandy, chalky or gravelly ground; tolerates a broad pH range. Avoid heavy, waterlogged soil.

Height

2-3 ft (0.6-0.9 m)

Spread

2-3 ft (0.6-0.9 m)

Flowers

Lavender-blue flowers from late spring through summer, with a further flush into early autumn after shearing.

Foliage

Small, opposite, softly hairy grey-green leaves with toothed edges and a minty scent when brushed or crushed.

Growth

Fast; usually forms a substantial clump within two growing seasons.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Low allergen
• Fragrant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.7 ft (0.53 m)

3. After 2 years

   2.5 ft (0.75 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Mildly toxic: may upset a stomach

Growth rate

Fast

• Water newly planted clumps deeply when the surrounding soil begins to dry.
• Plant in full sun with enough space for the stems to arch outward.
• Avoid rich feeding; excess nitrogen produces loose growth and fewer flowers.
• Keep mulch clear of the crown, especially in wet-winter climates.
• Divide crowded or thinning clumps in spring, usually every three to four years.

Pruning. After the main flower flush fades, shear stems back by about half, keeping some leafy growth, to encourage fresh foliage and more flowers. Cut remaining dead stems close to the ground in late winter or early spring before new shoots lengthen.

Early spring

Cut down old stems before new growth develops; divide established clumps if needed.

Spring

Plant in well-drained soil and water regularly while roots establish.

Late spring

Check that neighbouring plants are not shading or crowding the developing clump.

Summer

Shear after the main flowering flush and water if the soil is very dry.

Early autumn

Enjoy repeat flowers; avoid feeding or hard pruning as cold weather approaches.

Winter

Keep the crown free of wet leaves and check that water is not pooling around it.

• Repeat broad clumps along a sunny path for a soft edge; set plants back so stems do not block the walkway.
• Plant beneath shrub roses to cover bare lower stems and contrast lavender-blue flowers with rose blooms.
• Combine with ornamental grasses and upright perennials for contrasting shapes in a naturalistic border.
• Use in sunny gravel gardens with other drought-tolerant plants, allowing room for its spreading mound.

Garden styles it suits: Cottage garden, English country, New perennial (prairie), Pollinator garden, Dry gravel garden and Mediterranean.

Plant it with: Shrub roses, Salvia, Yarrow, Purple coneflower, Bearded iris and Feather reed grass.

Wildlife: Flowers provide nectar for bees and attract butterflies. Deer and rabbits usually leave the aromatic foliage alone, although no plant is completely browsing-proof.

• Flopping stems: provide full sun, avoid nitrogen-rich fertiliser and shear after the first flower flush.
• Crown or root rot: improve drainage or move the plant to a raised position; do not leave the crown under wet mulch.
• Powdery mildew: allow more airflow, avoid crowding and remove badly affected growth.
• Cats flattening young plants: protect new clumps with a temporary wire guard until established.

This cultivar is not known to be toxic to people, cats, dogs or horses, but cultivar-specific safety information is limited. It is not a food plant; eating large amounts of leaves or stems may cause digestive upset. Some cats are attracted to the foliage.

• Catnip (Nepeta cataria)

  Catnip has coarser, greener, more triangular leaves and mostly whitish flowers with purple markings, rather than the lavender-blue flower spikes of 'Six Hills Giant'.

• Catmint 'Walker's Low' (Nepeta 'Walker's Low')

  It has very similar foliage and flowers but generally makes a somewhat lower mound. Size overlaps, so a reliable label is the best way to confirm the cultivar.

• Russian sage (Salvia yangii)

  Russian sage has woody lower stems, more finely divided silvery leaves and an airier framework, usually flowering later in summer.

The common name catmint refers to its mint-family foliage and the attraction some cats show to its scent.

Propagation. Divide clumps in spring or take softwood cuttings in late spring or early summer. This cultivar is generally sterile; division and cuttings preserve its characteristics.

Accepted botanical name

Nepeta

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.