UK compost
What compost for aromatic aster in the UK?
Symphyotrichum oblongifolium
More about aromatic aster in the UK
Which compost aromatic aster needs
For aromatic aster the mix to buy is peat-free multipurpose compost. Excels in poor, dry, rocky or sandy soils, including alkaline shale and limestone-derived ground; tolerates clay if drained. Prefers neutral to alkaline pH. Avoid rich, moist soils that cause floppy, disease-prone growth.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 aromatic aster 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?
Aromatic Aster is straightforward: an ordinary peat-free multipurpose compost is right. For a big specimen or a pot it will live in for years, mixing in some loam-based John Innes No.2 or No.3 adds weight and holds nutrients longer. Ericaceous compost is not needed unless a plant is specifically a lime-hater.
For the full recipe, pH and drainage detail (US wording), see the aromatic aster soil & potting-mix guide.
Compost for Aromatic Aster in the UK — frequently asked questions
What compost should I use for aromatic aster in the UK?
Use peat-free multipurpose compost. Excels in poor, dry, rocky or sandy soils, including alkaline shale and limestone-derived ground; tolerates clay if drained. Prefers neutral to alkaline pH. Avoid rich, moist soils that cause floppy, disease-prone growth. 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 aromatic aster?
Yes. A good peat-free multipurpose compost is exactly right for aromatic aster. For a large or long-term pot you can mix in some John Innes No.2 or No.3 (loam-based) for extra weight and staying power.
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 aromatic aster perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does aromatic aster 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 aromatic aster need?
Always a pot with drainage holes. Lean, dry, well-drained soil. 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 aromatic aster care
See the full aromatic aster care guide, its UK watering and UK hardiness.