UK compost
What compost for small-flowered alumroot in the UK?
Heuchera micrantha
More about small-flowered alumroot in the UK
Which compost small-flowered alumroot needs
For small-flowered alumroot the mix to buy is peat-free ericaceous (lime-free) compost. Naturally found in humus-enriched, slightly acidic rocky soils with excellent drainage. Amend garden soil with leaf mould or fine-grade bark. Unlike some Heucheras, this species prefers a slightly more acidic soil than neutral. Avoid heavy clay.In British garden centres the bagged growing medium is sold simply as “compost” (multipurpose, ericaceous, or loam-based John Innes), which is a different thing from the rotted garden “compost” you make in a heap — for a pot you want the bagged kind.
Peat-free compost
Buy peat-free. The sale of peat compost to home gardeners is being phased out across the UK, and the RHS recommends peat-free on environmental grounds. A good peat-free multipurpose grows small-flowered alumroot perfectly well; the one habit to change is watering — peat-free dries faster at the surface while still moist below, so check by feel a knuckle deep rather than trusting the look of the top.
Ericaceous or multipurpose?
Small-flowered alumroot is a lime-hater: it needs an acidic, lime-free ericaceous compost. In ordinary (limey) multipurpose it slowly yellows between the leaf veins as it locks out iron. Buy a bag labelled "ericaceous", and in a hard-water area water with rainwater where you can, since tap water is slightly alkaline.
For the full recipe, pH and drainage detail (US wording), see the small-flowered alumroot soil & potting-mix guide.
Compost for Small-flowered alumroot in the UK — frequently asked questions
What compost should I use for small-flowered alumroot in the UK?
Use peat-free ericaceous (lime-free) compost. Naturally found in humus-enriched, slightly acidic rocky soils with excellent drainage. Amend garden soil with leaf mould or fine-grade bark. Unlike some Heucheras, this species prefers a slightly more acidic soil than neutral. Avoid heavy clay. In UK garden centres this is sold simply as "compost" — the bagged growing medium, not garden-made leaf-mould — so match the description above rather than a brand.
Can I use ordinary multipurpose compost for small-flowered alumroot?
No — small-flowered alumroot needs an acidic, lime-free (ericaceous) compost. Standard multipurpose is too limey and will slowly cause yellowing between the leaf veins (lime-induced chlorosis). Buy a bag labelled "ericaceous".
Should the compost be peat-free?
Yes. Sales of peat compost to home gardeners are being phased out in the UK, and the RHS recommends peat-free for environmental reasons. Modern peat-free multipurpose composts grow small-flowered alumroot perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does small-flowered alumroot need grit or perlite added?
Not essential, but a couple of handfuls of perlite in the mix improves aeration and guards against overwatering — useful on a cool, damp British windowsill where compost stays wet longer.
What pot and drainage does small-flowered alumroot need?
Always a pot with drainage holes. Humus-rich, moist, well-drained loam with good organic content; pH 5.5–6.5. Stand it on a saucer, empty any water that collects after watering, and never leave the pot sitting in a full outer cover — waterlogged compost in a cool UK room is the commonest cause of root rot.
More small-flowered alumroot care
See the full small-flowered alumroot care guide, its UK watering and UK hardiness.