Repotting guide

When & how to repot Six Hills Giant Catmint (Nepeta x faassenii 'Six Hills Giant')

Also called Six Hills Giant catmint, tall catmint.

More about six hills giant catmint

About Six Hills Giant Catmint

Nepeta x faassenii 'Six Hills Giant' · also called Six Hills Giant catmint, tall catmint · flowering

Six Hills Giant is the tallest, most vigorous garden catmint, sending up arching stems of grey-green foliage smothered in violet-blue flowers from early summer to autumn. Tougher and bigger than common catmint, it makes a billowing front-of-border drift, edges paths and underplants roses. Bees adore it, and shearing after the first flush guarantees a strong rebloom.

Mature size: 75-90 cm tall and 60-90 cm wide.

How to tell six hills giant catmint needs repotting

Repotting on a calendar is less reliable than reading the plant. For six hills giant catmint, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot six hills giant catmint

Every 2–3 years, into bone-dry mix. Six Hills Giant Catmint's growth habit — large, vigorous, upright-then-arching clump of branching aromatic stems forming a tall, loose, fountain-like mound. — sets the pace. Six Hills Giant is the tallest, most vigorous garden catmint, sending up arching stems of grey-green foliage smothered in violet-blue flowers from early summer to autumn. Tougher and bigger than common catmint, it makes a billowing front-of-border drift, edges paths and underplants roses. Bees adore it, and shearing after the first flush guarantees a strong rebloom.

What size pot to step six hills giant catmint up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Six Hills Giant Catmint stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot six hills giant catmint

Spring or summer, while six hills giant catmint is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting six hills giant catmint

Repot dry. Do not water six hills giant catmint for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty free-draining loam or sandy soil, neutral to alkaline ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set six hills giant catmint at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep six hills giant catmint completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for six hills giant catmint

Six Hills Giant Catmint wants free-draining loam or sandy soil, neutral to alkaline. Thrives on poor, gritty, chalky ground. Rich or wet soils make this big cultivar flop badly and shorten its life. Improve clay with grit before planting. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting six hills giant catmint — frequently asked questions

How often should you repot six hills giant catmint?

Every 2–3 years, into bone-dry mix for six hills giant catmint. Repot six hills giant catmint every 2–3 years into a snug pot of free-draining loam or sandy soil, neutral to alkaline, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does six hills giant catmint need?

When is the best time of year to repot six hills giant catmint?

Should you water six hills giant catmint after repotting?

No — not straight away. Repot six hills giant catmint into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise six hills giant catmint after repotting?

Not immediately. Wait about 3 weeks after repotting six hills giant catmint. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.