HarvestingIn September, October and NovemberDig established marshmallow roots
Harvest roots only from 2+ year clumps, replant divisions, scrub, slice, and dry. Older roots have the best mucilage and harvesting young plants weakens the patch.
Marshmallow
Althaea officinalis
Family Malvaceae
The candy borrowed its name from this plant. Marshmallow — the original one — is a tall, soft-leaved cottage herb whose roots and leaves brew the famously silky, soothing tea herbalists have kept close for centuries, topped in summer with pale mallow flowers that bees appreciate.
Where the ground stays damp — a rain garden's fringe, a low bed edge — it rises in a graceful velvety column year after year, with roots worth digging once a plant is well established. Few herbs suit a wet spot so well. Give the damp corner its classic resident.
Full Sun to Part Shade
Moderate water
Moderate growth
Attracts bees
From the print shop
Growing marshmallow? Hang it.
Our Plant Library collection carries marshmallow — Althaea officinalis, print Nº 295, “Marshmallow.”
526 designsfrom $12.99white or black backgroundmatte poster, unframed
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Will it fruit where you are?
Enter your ZIP — we look up your USDA hardiness zone (2023 map) and check it against what marshmallow actually needs.
Hardy inZones 3-9Marshmallow · Common problems
Common marshmallow problems
Pests, diseases and weather to keep an eye on.
Pests
3 problems on file
Diseases
2 problems on file
Marshmallow · Growing & propagation
Growing marshmallow
Light, water, soil, propagation and the season’s jobs.
What it needsThe details
- Light
- Full Sun to Part Shade
- Water
- Moderate-High - likes steady moisture
Soil- Rich, moist, well-drained
Tolerates wet edges · pH 6.0 - 7.5
Fertilizer- Compost in spring
Pruning- Late Winter
Cut dead stems to ground; divide or refresh older clumps as needed.
Spacing- 24-30 in
How to plant & propagate marshmallow
- Propagate
- Division or seed
Marshmallow · Seasonal care & spray guidance
The marshmallow growing playbook
Field-tested instructions for every job marshmallow asks of you, compiled from university extension guidance — in the order the season brings them.
When to spray marshmallow
Growing season. Improve airflow; remove rusted leaves.
After harvest
autumn, and putting it to bed
1 jobHarvestingIn September, October and NovemberMarshmallow · Calculators & field guides
A little help in the garden.
Calculators for the figures. Field guides for the hands-on work.
Marshmallow · Yearly calendar
The marshmallow year, month by month
What marshmallow asks for, month by month.
Jan
No calendar activity is listed for this month.
MonthJanFebMarAprMayJunJulAugSepOctNovDec
BloomPruneHarvestBloomJuly, then September
PruneFebruary to March
HarvestJune to November
What each band means
- Bloom — flowers open — pollinators working, frost on blossoms is the danger.
- Prune — shape it now — cuts heal cleanly and structure is visible.
- Harvest — picking time — check ripeness every few days.
These are the species' typical months — expect them a few weeks earlier in warm zones and later in cold ones. Watch the plant, not just the calendar.
Marshmallow · Ecology & uses
Ecology & uses
What it does for the garden, and what it is grown for.
Althaea officinalis
Marshmallow in the garden system
- Herbaceous layer perennial
- Nectary/insectary
Attracts- Bees
Habitat- Wetland
- Moisture
- Wetland / wet-tolerant
Deer- Browsed
Protect young plants
Origin- Introduced
What marshmallow is grown for
! Some parts toxic — see notesCaution: mucilage may interfere with medication absorption; separate from meds
- Use
- Root/leaf tea
- Use
- Wet-site herb
- Use
- Pollinators
- Use
- Cottage herb
- Edible value
- 3/5
- Traditional use rating
- 4/5 in herbal tradition
Harvesting & storing marshmallow
Leaves/flowers summer; roots fall of year 2+.
Edibility, identification, and traditional-use notes here are general reference — not medical or veterinary advice, and not a claim that any plant treats or prevents anything. Medicinal ratings record how strongly a plant features in herbal tradition, nothing more. Never eat or dose a plant you have not positively identified. More on how to use this library.
Marshmallow · Varieties & cultivars
Choosing a marshmallow variety
Match the plant to your climate, season and available space.
Species
Sources & plant identity
Know what you’re growing.
See where the knowledge comes from.
Marshmallow
Althaea officinalis
The plant, at a glance.
- Botanical name
- Althaea officinalis
- Plant family
- Malvaceae
- Growth habit
- Perennial
- Origin
- Introduced
- USDA plant symbol
- ALOF2
- Invasive risk
- Low
- Other names
- Althaea officinalis (marsh mallow)
Every garden is different.
Hardiness, size and timing vary with your cultivar, soil and climate.
Rooted in research.
University extension research, brought together with hands-on growing experience at Story Thyme Farms.
Explore Marshmallow’s sources2 reference links
for Marshmallow
for Marshmallow
Research from these sources
Publisher marks identify sources, not sponsorship or endorsement.
Questions
Marshmallow questions, answered straight.
Is marshmallow safe for kids and pets?
With care. Caution: mucilage may interfere with medication absorption; separate from meds Site it accordingly if children or pets roam the garden. This is general reference, not medical or veterinary advice — call a vet or poison control if something has actually been eaten.
When do you harvest marshmallow?
Leaves/flowers summer; roots fall of year 2+.
How do you propagate marshmallow?
Division or seed.
Elsewhere
Where marshmallow sits in the library.
Comfrey
Lavender
Rosemary
Anise Hyssop