Marsh Mallow

Althaea officinalis

The mallow that gave the confection its name, and one that asks for damper ground than most herbs will take.

Light Happy in full sun, and untroubled by a few hours of shade.
Water Wants soil that stays damp; water through dry spells rather than waiting for it to flag.
Height 1.2 m
Spread 23.6 in
Spacing 60 cm

Spacing & sowing

Plant spacing
23.6 in
In-row spacing
23.6 in
Between rows
2 ft 6 in
Square-foot density
Not suited to SFG

Growing

Type
Herb · Perennial
Botanical family
Mixed / other
Sunlight
Happy in full sun, and untroubled by a few hours of shade.
Watering
Wants soil that stays damp; water through dry spells rather than waiting for it to flag.
Feeding
A light feed in spring is all it asks for.
Frost tolerant
Yes
Flowering
July
Pruning
Cut everything down to ground level in late autumn.

Through the year

  • Mar–Jul Spring Growth
  • Jul–Sep Flowering
  • Sep–Oct Growing
  • Oct–Nov Leaf Fall
  • Nov–Dec Winter Dormancy
  • Jan–Mar Winter Dormancy

Garden allies

Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant

  • Beneficial nematodes Steinernema & Heterorhabditis spp.

    Microscopic worms watered onto damp soil that hunt down soil-dwelling grubs and release a bacterium that kills them within days. Timing is the whole thing: warm, damp soil and a small target grub, which means late summer for most of what they are used against.

  • Frogs & toads Anura

    A resident toad works the beds every night for slugs, cutworms, and weevils. Recruit them with water — even a sunken basin pond — plus damp shade and an upturned-pot toad house; skip the slug pellets that poison their prey.

  • Ground beetle Carabidae

    Fast, glossy night hunters that patrol the soil surface for slugs, cutworms, and root-fly larvae. Give them daytime cover — thick perennial edges, stepping stones, a log — and skip the tillage that wrecks their burrows.

    Plant nearby LavenderMintThyme
  • Hedgehog Erinaceus europaeus

    A European animal, and worth saying so plainly: there are no hedgehogs in North America, and the ally that does the same night shift here is the toad, the opossum or the ground beetle. Where they do occur, cut a gap in the fence and skip the pellets.

  • Centipedes Chilopoda

    Flat, fast, one pair of legs to a segment — and a predator, unlike the slow round millipede it is constantly confused with. It hunts slugs, cutworms, springtails and woodlice by night under mulch and stones. Learn the difference and leave this one alone.

  • Garden birds Passeriformes

    Both things are true: birds strip your currants and a brood of blue tits takes several thousand caterpillars out of one fruit tree in a fortnight. Net what you must and welcome them everywhere else — a nest box near the apples is worth more than a spray.

  • Rove beetle Staphylinidae

    Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.

    Plant nearby MintThyme
  • Salamanders & newts Caudata

    Damp-loving hunters of slugs, worms, woodlice and beetle larvae that spend the day under a log or a stone and work the beds at night. Companions to the toads: they want the same damp shade, the same log pile, and the same absence of slug pellets.

  • Snakes & lizards Colubridae & Phrynosomatidae

    A garter snake works the beds for slugs and voles and a fence lizard clears grasshoppers off a sunny wall. Almost every snake a gardener meets is harmless and useful; give them a log pile, a warm flat stone and a bit of cover and they stay.