Nepeta 'Six Hills Giant'

 

There’s something irresistibly soft and generous about Nepeta ‘Six Hills Giant’. With its aromatic, silvery foliage and haze of lavender-blue flower spikes, this catmint earns its place in every sun-drenched border. But it’s not just a pretty face—this plant is a magnet for bees, butterflies, and beneficial insects, and once settled, it needs remarkably little to thrive. With the right light, soil, and occasional pruning, Nepeta rewards you with months of fragrance, colour, and movement. Here's how to care for it the easy, wildlife-friendly way.

A Place in the Sun

Nepeta ‘Six Hills Giant’ thrives in full sun, where its flower spikes can reach their full potential and its compact mound retains its shape. While it will tolerate a little shade, avoid planting it in deep shade, where its bloom count will drop, and its form may become straggly.

It’s a perfect fit for informal cottage borders, pollinator-friendly gardens, gravel planting, or the edges of pathways where its soft stems can tumble gently into the walkway. Plant it near roses or tall perennials for a beautiful layered effect.

Soil: Drainage is Everything

This catmint prefers soil that drains well, no matter the type. It copes happily with sandy, chalky, or loamy ground and accepts a wide pH range—from slightly acidic to alkaline. What it won’t forgive is sitting in soggy, compacted soil. If that’s a concern, raise the planting area slightly or dig in plenty of grit or organic matter.

Before planting, enrich the soil with well-rotted compost or leaf mould to support early root development and long-term structure. It doesn’t need rich soil—in fact, overly fertile ground can encourage lanky, floppy growth.

In Summary:

• Free-draining soil (essential)

• Tolerates sandy, chalky, loamy, or gravelly textures

• Neutral to slightly alkaline pH preferred

• Moderate fertility with organic matter at planting

Watering: Drought-Friendly but Not Forgettable

In its first year, water your Nepeta regularly to help it settle. Once established, it becomes drought-tolerant and generally needs little more than a deep soak during extended dry spells.

Avoid overwatering, especially in heavy soils. Constantly moist conditions lead to weak growth and increased risk of mildew. Instead, let the soil dry between waterings and aim to water at the base of the plant to reduce humidity around foliage.

For containers or very hot spells, check moisture levels more often—potted plants dry out faster.

Feeding and Mulching: Less is More

Nepeta is not a hungry plant. A spring mulch with well-rotted compost or leaf mould helps retain moisture, improve soil texture, and support healthy flowering. Avoid overfeeding, especially with nitrogen-rich fertilisers, which can encourage lush, leggy stems at the expense of flowers.

Feeding Tips:

• Mulch lightly in early spring with organic matter

• Avoid chemical fertilisers and rich manures

• Don’t feed mid-season—pruning is more effective for repeat bloom

Pruning: The Secret to Long Flowering

For months of colour, the right pruning routine makes all the difference. After the first flush of flowers in early or mid-summer, shear back the plant by around one-third. This encourages a neat shape and triggers a second bloom that carries the display through to autumn.

Come late winter or early spring, cut the entire clump back hard to a low mound to refresh the plant and remove any dead growth. You can also deadhead individual flower stalks throughout summer to extend blooming.

In rich soils or windy spots, occasional staking may be needed, or consider the Chelsea Chop in late May for a tidier form.

Spacing and Planting a Border or Hedge

To create a flowing border or informal hedge with Nepeta ‘Six Hills Giant’, plant in a single row with 30–45cm between plants. Closer spacing (30cm) will knit together faster, ideal for smaller pots or quicker coverage. Leave more space for mature plants or in breezier locations.

For best results:

• Plant in spring or early autumn

• Mix with companion pollinator plants or repeat among roses

• Mulch after planting and water well in the first few weeks

Propagation and Division

Every 3–4 years, divide mature plants in early spring or autumn to maintain vigour and prevent overcrowding. Dividing is also an easy way to increase your stock—each new clump will establish quickly.

You can also take softwood cuttings in early summer from healthy non-flowering shoots.

Wildlife Wonders

One of the best things about Nepeta ‘Six Hills Giant’ is its value to garden wildlife. Flower spikes are a buffet for bees, hoverflies, and butterflies throughout the summer months. Its soft, scented foliage is even used by some caterpillar species, including the pretty mint moth.

It’s also untroubled by rabbits or deer, and its strong scent helps deter aphids and unwanted pests nearby.

Wildlife Benefits:

• Long-flowering nectar source for bees and butterflies

• Supports mint moth caterpillars

• Aromatic shelter for insects

• Pest-resistant and non-toxic to pets

Pests and Problems

Nepeta is generally low-maintenance and rarely affected by pests. However, keep an eye out for leafhoppers or powdery mildew in crowded or overly damp conditions. Good spacing and airflow are your best defence.

If mildew appears, trim back affected stems and thin nearby planting to allow air to circulate.

Container Care

If you’re short on border space, Nepeta ‘Six Hills Giant’ is also a reliable performer in pots.

Use a free-draining compost mix and a wide, shallow container that allows room for the plant’s natural spread. Water regularly in dry periods, and shear back after flowering to maintain a neat shape.

Top Tips:

• Choose terracotta or breathable pots with drainage holes

• Mulch the surface with grit or bark to reduce splash and evaporation

• Refresh compost every 2–3 years and divide if needed

Final Note: Summer’s Soft Constant

Whether edging paths, weaving through roses, or tumbling from pots, Nepeta ‘Six Hills Giant’ brings reliable rhythm to any summer garden. It hums with bees, sways with breeze, and asks for very little in return. Give it sun, a dry root run, and the occasional haircut, and it will return the favour tenfold—in colour, scent, and endless pollinator visits.