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Sweet Annie

Artemisia annua
Also known as: Sweet Wormwood, Sweet Sagewort, Annual Wormwood, Qinghao

Sweet Annie is a herb in the Asteraceae family. It grows best in full sun with dry to medium moisture, and is listed for USDA zones 4-9. Plants reach harvest about 102–138 days after planting.

Varieties

1 from High Mowing · sorted by days to maturity
  • Sweet Annie102–138 days

    Cut or dried flowers; 48-72” tall; Reseeding annual

    Aromatic spears of delicate, ferny foliage with multitudes of tiny, light yellow flowers. An excellent filler plant used in fresh and dried arrangements with a sweet smell that lasts even after being dried. Plants are vigorous and can reach towering heights of up to 6’ tall in warm regions. A must-have for the cut flower and dried flower assortment. 22M seeds/g

    Growing notes: We have selected these easy-to-grow flower varieties for their individual beauty, for the beneficial insects they attract, and/or suitability for cut flower production. By offering an assortment of hues, heights, growth habits and appearances, we strive to fill your flower needs, whether you are adding color to your home garden or selling bouquets for market. Our varieties are tried-and-true standards that are sure to perform well in a wide range of growing conditions. Many of these varieties are well suited for succession plantings to ensure a continuous harvest throughout the season. Days to maturity are from seeding. M=1,000.

    View on High Mowing
Family
Asteraceae
Category
Herb
Form
Bush
Lifecycle
annual
Zone
4-9
Height
5–7 ft
Spread
2–3 ft
Sun
Full sun
Water
Dry to medium

Plan your sweet annie planting

Add sweet annie to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.

Start your free plan →

At a glance

Days to harvest
102–138 days
From transplant or sow to first harvest
Harvest style
Keep picking
Crops over several weeks
After harvest
Use within days
Quality eases off after peak
Frost tolerance
Tender · to ~32°F
Lowest temperature the foliage usually survives

Storing & preserving

Refrigerate stems in water, or wrap in a damp towel for a few days.

  • Dry: Dehydrate or air-dry, then store airtight away from light.
  • Freeze: Freeze chopped in oil or water in ice-cube trays.

General home-preservation guidance — for tested processing times and safety, follow the National Center for Home Food Preservation.

Growing timeline

When to plant and harvest sweet anniePlanting timeline for sweet annie, relative to last frost: start indoors from 6 weeks before last frost to around last frost; grow from around last frost to 15 weeks after last frost; harvest from 15 weeks after last frost to 20 weeks after last frost.Start indoorsGrowHarvestLast frostTransplant
Start sweet annie indoors ~6 weeks before transplanting around last frost; first harvest 15 weeks after last frost.
Seed to transplant
28-42 days
Outdoor planting
0 to 14 days vs frost
Propagation
Seed
Schedule anchor
Last Frost

Companion planting — with cited sources

From US/Canada cooperative-extension publications and peer-reviewed studies. Evidence-tier dots show how strongly each recommendation is backed: ●●● peer-reviewed mechanism · ●● extension consensus · traditional knowledge with a plausible mechanism.

Avoid planting near (2)

  • Common BeanEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative

    Sweet Annie (annual wormwood) is allelopathic — artemisinin and related compounds suppress germination and growth of neighboring plants; keep out of cultivated beds.

    Source: S7, Putnam & Tang

  • Common TomatoEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative

    Most vegetables are inhibited near Sweet Annie's allelopathic residues.

    Source: S7, Putnam & Tang

Sources cited

S36
Putnam & Tang (eds.), 1986 — allelopathy compendium
S7
University of Minnesota Extension

Care & troubleshooting— extension-sourced, with citations

When to feed, prune & water

Attract beneficial insects and protect pollinators

Protection
  • Routine carePlant insectary flowers and tolerate light pestsstrong evidence — extension confidence

    Grow a diversity of flowering plants (including small-flowered umbels and asters) to feed predators and parasitoids, and tolerate low pest numbers so natural enemies have prey to stick around.

    Source: UC IPM; UMN Extension

  • Routine careNever spray open bloomsstrong evidence — extension confidence

    Avoid insecticides on flowering plants and apply any needed sprays in the evening when pollinators aren't active, and favor selective products over broad-spectrum ones to spare bees and beneficials.

    Source: UC IPM

Mulch to suppress weeds and retain moisture

Mulch
  • Routine careApply organic mulch around plantsstrong evidence — extension confidence

    Spread a few inches of straw, shredded leaves, or compost around established plants (keeping it off stems) to hold soil moisture, suppress weeds, and moderate soil temperature; wait until soil has warmed for heat-loving crops.

    Source: UMN Extension; Missouri Botanical Garden

Protect the garden from rabbits and voles

Protection
  • Routine careFence out rabbitsstrong evidence — extension confidence

    Surround beds with 1-inch mesh chicken wire at least 2 feet tall with the bottom buried or staked down a few inches so rabbits can't push under it.

    Source: UMN Extension; Cornell CCE

  • Routine careReduce vole habitat and guard stemsstrong evidence — extension confidence

    Keep grass and mulch pulled back from plant bases and crowns to remove vole cover, mow surrounding vegetation, and use hardware-cloth guards around vulnerable woody stems before winter.

    Source: UMN Extension; Cornell CCE

Clean up debris and sanitize at season end

Sanitation

Unusual this time of year.

  • Routine careRemove spent plants and fallen debrisstrong evidence — extension confidence

    Pull and clear old plants, dropped fruit, and leaf litter at season end, since many pests and diseases overwinter in this debris; dispose of diseased material rather than composting it.

    Source: UMN Extension; Cornell

  • Routine careClean tools, stakes, and cagesmoderate evidence — extension confidence

    Wash and sanitize stakes, cages, and tools that touched diseased plants before storing or reusing them to avoid carrying pathogens into next season.

    Source: Cornell; UMN Extension

Harden off seedlings

Protection

Unusual this time of year.

Read: starting seeds indoors

Succession-sow quick crops

Care

Unusual this time of year.

Something looks wrong?

Describe what you see on your sweet annieand we'll rank the likely causes — most likely first, least-invasive fix first.

Tomato spotted wilt virus

Virussevere

Symptoms: bronzing or purpling of young leaves; ringspots and concentric rings on leaves and fruit; one-sided or stunted growth; dark streaks on stems; mottled or blotchy ripening fruit

  • CulturalRemove infected plants (cannot be cured)strong evidence — extension confidence

    There is no cure once a plant is infected, so promptly pull and dispose of symptomatic plants to reduce the virus reservoir that thrips spread to healthy plants.

    Source: UC IPM; UMN Extension

  • CulturalStart clean and control weeds and thripsstrong evidence — extension confidence

    Use virus- and thrips-free transplants, choose resistant varieties (Sw-5 tomatoes, Tsw peppers) where available, and control weeds around the garden that harbor both virus and thrips vectors.

    Source: UC IPM; UF/IFAS

Read: diagnosing leaf spots & yellowing

White mold (Sclerotinia stem rot)

Diseasesevere

Symptoms: water-soaked stem or branch lesions; fluffy white cottony mold on stems and pods; sudden wilting of part of a plant; hard black sclerotia inside or on stems; collapse during cool wet bloom periods

  • CulturalRemove infected plants (manage, not cure)strong evidence — extension confidence

    There's no cure for an infected plant; cut out and bag affected plants including the black sclerotia, and don't compost them, since sclerotia survive years in soil.

    Source: UMN Extension; UC IPM

  • CulturalOpen the canopy and rotatestrong evidence — extension confidence

    Space plants widely, control weeds, orient rows to prevailing wind, and avoid overhead watering at bloom to dry the canopy; rotate to non-host crops (corn or other grasses) for several years.

    Source: UMN Extension; UC IPM

  • CulturalWater at the base, not overheadmoderate evidence — extension confidence

    Use drip or soaker irrigation to keep foliage and the soil surface drier, which discourages the sclerotia germination and mycelial growth that drive white mold.

    Source: UC IPM

Botrytis gray mold

Diseasemoderate

Symptoms: fuzzy gray-brown mold on leaves, stems, flowers, or fruit; soft watery rot on fruit and blossoms; dieback from cut or wounded stems; mold spreading in cool humid still conditions; blighted flowers that fail to set

  • CulturalRemove infected tissue and old blossomsstrong evidence — extension confidence

    Prune out moldy leaves, stems, and fruit and clear fallen blossoms and debris where the fungus gets started, disposing of them rather than composting.

    Source: UMN Extension; Cornell

  • CulturalImprove airflow and reduce leaf wetnessstrong evidence — extension confidence

    Space and stake plants for good air movement, water at the base in the morning, and harvest ripe fruit promptly so botrytis has fewer cool, humid, wet surfaces to colonize.

    Source: UMN Extension; Cornell

Japanese beetles

Pestmoderate

Symptoms: leaves skeletonized between veins; lacy chewed foliage; metallic green-bronze beetles clustered on plants; feeding worst in warm midsummer sun

Leafhoppers & aster yellows

Diseasemoderate

Symptoms: small wedge-shaped insects hop from leaves; stippled or yellowed foliage; with aster yellows: yellow stunted growth, witches-broom of thin shoots, deformed bitter carrots

Powdery mildew

Diseasemoderate

Symptoms: white powdery coating on upper leaf surfaces; starts as spots then spreads; leaves yellow and dry under the coating

  • CulturalImprove airflow + remove worst leavesstrong evidence — extension confidence

    Cut out the most heavily coated leaves and thin for airflow; avoid wetting foliage late in the day.

    Source: UC IPM

  • OrganicPotassium-bicarbonate or sulfur - label use only· every 1 wk · ~4 wksmoderate evidence — extension confidence

    Apply a labeled potassium-bicarbonate or sulfur fungicide weekly per the label. No sulfur within 2 weeks of oil or in high heat.

    Always follow the product label — it is the law.

    Source: UC IPM

Root rot from overwatering / poor drainage

Diseasemoderate

Symptoms: stunted yellowing plants that wilt despite wet soil; soft brown mushy roots; sloughing root outer layer leaving thread-like core; poor growth in low or compacted wet spots; seedlings collapsing at the soil line

Slugs & snails

Pestmoderate

Symptoms: large ragged holes with smooth edges; slimy silvery trails; damage worst after rain and overnight

  • CulturalTrap, hand-pick at night, reduce cover· every 2 days · ~3 wksstrong evidence — extension confidence

    Pick at night with a flashlight, set shallow beer traps, water in the morning so soil dries by dusk, and clear damp hiding spots.

    Source: UC IPM: Snails and Slugs

  • OrganicIron-phosphate bait - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence

    Scatter a labeled iron-phosphate slug bait sparingly per the label; it's pet- and wildlife-safer than metaldehyde.

    Always follow the product label — it is the law.

    Source: UC IPM

Tarnished plant bug / lygus

Pestmoderate

Symptoms: deformed or puckered new growth; pitted or scarred stems and leaves; aborted or misshapen buds and fruit; catfaced or dimpled strawberries; small bronze-green bugs with triangular back marking

  • CulturalManage surrounding weedsstrong evidence — extension confidence

    Keep broadleaf weeds mowed or removed around the garden, since lygus build up on flowering weeds and move to crops as those weeds dry down; avoid mowing large weedy areas right beside fruiting crops at bloom.

    Source: UC IPM

  • CulturalVacuum or shake plants to monitor and reduce· every 5 daysmoderate evidence — extension confidence

    Tap plants over a light-colored tray to check for nymphs; a handheld vacuum used once or twice weekly can hold low to moderate numbers down on small plantings.

    Source: UC IPM

  • OrganicTreat nymphs if damage is building· every 1 wkmoderate evidence — extension confidence

    For active nymph infestations, azadirachtin or a Beauveria bassiana product can give some control per the label; preserve the parasitic wasps and other natural enemies that help suppress lygus.

    Always follow the product label — it is the law.

    Source: UC IPM

Whiteflies

Pestmoderate

Symptoms: clouds of tiny white insects fly up when plants are disturbed; yellowing stippled leaves; sticky honeydew and black sooty mold; weak stunted growth

  • CulturalRemove infested leaves and hose off· every 4 daysmoderate evidence — extension confidence

    Pick off and discard heavily infested lower leaves and rinse colonies off undersides with a strong spray of water; yellow sticky cards help monitor numbers.

    Source: UC IPM: Whiteflies

  • OrganicApply a labeled soap or oil· every 1 wk · ~3 wksmoderate evidence — extension confidence

    Apply a labeled insecticidal soap or neem oil per the label, covering leaf undersides; these reduce but won't eliminate whiteflies, so repeat as needed.

    Always follow the product label — it is the law.

    Source: UC IPM: Whiteflies

Cutworms

Pestmoderate

Unusual this time of year.

Symptoms: seedlings cut off at soil line; transplants toppled overnight; wilted clipped plants in a row; chewed stems near ground; gray-brown caterpillars curled in soil

  • CulturalPlace stem collars on transplantsstrong evidence — extension confidence

    Push a collar (cardboard tube, can, or cup with bottom removed) a couple inches into the soil around each stem so it extends a few inches above ground; this blocks cutworms from reaching the stem.

    Source: UMN Extension: Cutworms; UC IPM: Cutworms

  • CulturalScout soil and hand-remove· every 3 days · ~2 wksstrong evidence — extension confidence

    In the evening or early morning, check the soil around damaged plants and remove curled larvae by hand; tilling beds about two weeks before planting also reduces larvae and pupae.

    Source: UMN Extension: Cutworms; UC IPM: Cutworms

  • OrganicApply a labeled Bt or spinosad· every 1 wk · ~3 wksmoderate evidence — extension confidence

    If damage continues, apply a labeled Bacillus thuringiensis (kurstaki) or spinosad product per the label, targeting small larvae; Bt works best on young first- and second-instar cutworms.

    Always follow the product label — it is the law.

    Source: UC IPM: Cutworms

Aphids

Pestlow

Symptoms: clusters of tiny soft-bodied insects on new growth and undersides; sticky honeydew or sooty mold; curled distorted new leaves; ants tending them

  • CulturalBlast off with water· every 3 days · ~2 wksstrong evidence — extension confidence

    Knock colonies off with a strong jet of water in the morning; repeat every few days. Light infestations rarely need more.

    Source: UC IPM: Aphids

  • OrganicInsecticidal soap - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence

    For persistent colonies apply insecticidal soap to undersides per label. Avoid open flowers.

    Always follow the product label — it is the law.

    Source: UC IPM

Bolting (premature flowering)

Disorderlow

Symptoms: plant sends up a tall central flower stalk; leaves turn bitter; growth turns leggy; happens during heat and long days in lettuce, spinach, and brassicas

Earwigs

Pestlow

Symptoms: ragged irregular holes in leaves and seedlings; chewed flower petals; damage to soft fruit; pincered insects hiding in dark moist spots; feeding noticed mainly overnight

  • CulturalTrap and remove· every 1 days · ~2 wksstrong evidence — extension confidence

    Set rolled damp newspaper, low tuna-style cans of oil, or short tubes near plants at dusk, then dump trapped earwigs into soapy water each morning; reduce mulch and damp hiding spots near vulnerable seedlings.

    Source: UC IPM

  • OrganicApply a bait only if damage persists· every 1 wkmoderate evidence — extension confidence

    Established plants usually tolerate earwigs, which also eat aphids; if seedlings are being destroyed, a spinosad-based bait labeled for earwigs can help per the label.

    Always follow the product label — it is the law.

    Source: UC IPM

Transplant shock

Disorderlow

Unusual this time of year.

Symptoms: wilting or drooping right after transplanting; stalled growth for days after setting out; leaf scorch or edge browning on new transplants; temporary yellowing; recovery once roots establish

  • CulturalWater in well and provide shade· every 1 days · ~1 wksstrong evidence — extension confidence

    Water transplants in thoroughly at planting and keep the root zone evenly moist for the first week or two, and provide temporary shade during hot, sunny, or windy spells to reduce stress while roots establish.

    Source: UMN Extension; Missouri Botanical Garden

  • CulturalHarden off and plant gently next timestrong evidence — extension confidence

    Most plants recover on their own; to prevent recurrence, harden off seedlings before planting, set them out in mild weather or evening, and avoid disturbing the roots when transplanting.

    Source: UMN Extension