Soil & potting mix
Best soil for 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.
Preferred mix: Free-draining loam or sandy soil, neutral to alkaline
Watch for — Crown rot in wet sites: Collapse and blackening at the base in poorly drained or winter-wet ground. Plant high in sharply drained soil to keep the crown dry.
Why six hills giant catmint needs this mix
Six Hills Giant Catmint flowers hardest in a rich but free-draining loam — fed enough to fuel the display, open enough that the roots never waterlog.
- Flowering is expensive for six hills giant catmint: producing buds, blooms and seed draws heavily on nutrients and steady moisture, so the soil has to keep delivering all season.
- A loam-based mix holds nutrients and water far more evenly than a light peat mix, which means a longer, more reliable flowering period.
- It still needs sharp drainage — most flowering plants resent cold, wet feet far more than they resent being a little lean.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons six hills giant catmint struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- A thin, hungry or sandy mix gives six hills giant catmint weak growth and few, short-lived flowers — it simply runs out of fuel.
- A heavy, badly drained soil rots the roots or crown, often over a wet winter, and you lose the plant before it ever flowers again.
- Over-rich, high-nitrogen mixes can push lush leaf at the expense of flowers — balance, not excess, is the aim.
Either starving six hills giant catmint in a thin mix or drowning it in a heavy, badly drained one. It wants the rich-but-free-draining middle, plus a flowering (higher-potassium) feed in season.
pH — does it matter for six hills giant catmint?
Most flowering plants, including six hills giant catmint, do well around pH 6.0-7.0. A cheap soil test is worth it outdoors; one notable exception is any acid-lover (such as some hydrangeas), where pH directly changes flower colour.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
A quality bagged compost works for six hills giant catmint in pots if you add grit and a flowering feed. In beds, improving the existing soil with compost and ensuring drainage beats any bag.
Drainage and the pot
Free drainage protects the roots and especially the crown over winter — raised beds, grit in the planting hole and never a waterlogged spot. Containers must have a clear drainage hole.
For perennials, refresh the top layer and feed each spring rather than disturbing the roots; for container displays, start with fresh rich mix each season. When the time comes, our repotting guide for six hills giant catmint covers the timing and technique step by step.
Six Hills Giant Catmint soil — frequently asked questions
What is the best soil mix for six hills giant catmint?
3 parts good loam or quality peat-free compost : 1 part well-rotted compost or leaf mould : 1 part grit or perlite. Flowering is expensive for six hills giant catmint: producing buds, blooms and seed draws heavily on nutrients and steady moisture, so the soil has to keep delivering all season.
Can I use normal potting soil for six hills giant catmint?
A thin, hungry or sandy mix gives six hills giant catmint weak growth and few, short-lived flowers — it simply runs out of fuel. A quality bagged compost works for six hills giant catmint in pots if you add grit and a flowering feed. In beds, improving the existing soil with compost and ensuring drainage beats any bag.
Does six hills giant catmint need a special pH?
Most flowering plants, including six hills giant catmint, do well around pH 6.0-7.0. A cheap soil test is worth it outdoors; one notable exception is any acid-lover (such as some hydrangeas), where pH directly changes flower colour.
Should I buy a bagged mix or make my own for six hills giant catmint?
A quality bagged compost works for six hills giant catmint in pots if you add grit and a flowering feed. In beds, improving the existing soil with compost and ensuring drainage beats any bag.
How often should I refresh the soil for six hills giant catmint?
For perennials, refresh the top layer and feed each spring rather than disturbing the roots; for container displays, start with fresh rich mix each season. Free drainage protects the roots and especially the crown over winter — raised beds, grit in the planting hole and never a waterlogged spot. Containers must have a clear drainage hole.
Keep reading
- Six Hills Giant Catmint care — the full brief (light, water, humidity, problems, pet safety)
- How often to water six hills giant catmint — the schedule the mix feeds into
- Repotting six hills giant catmint — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Should I water my plant? The simple check first
- Why is my plant wilting? Wet vs dry diagnosis
- Root rot — how the wrong soil starts it, and how to save the plant
- Best soil for peace lily
- Best soil for bird of paradise
- Best soil for hoya
- All 5561 soil and potting-mix guides in the Growli library