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Sweet William

Dianthus barbatus
Also known as: Dianthus, Bearded Pink

Sweet William is a flower in the Caryophyllaceae family. It grows best in full sun with dry to medium moisture, and is listed for USDA zones 3-9. Plants reach maturity about 100–112 days after planting and sit about 12 inches apart.

Varieties

3 from High Mowing & True Leaf Market · sorted by days to maturity
  • Volcano Mix100–110 days

    First year flowering; 20-24” tall; Perennial

    A lovely mix of multi-bloom stems ranging from pink and purple to white with a nice variety of petal coloration. This first-year flowering Dianthus is best grown as an annual and has a nice mixture of colors, perfectly blended for bouquets and in-the- garden beauty. Flower petals are edible and should be removed from the stem before consumption, offering a spicy, mild, clove flavor. Plants are vigorous and high-yielding, making it a reliable mix for cut flower production. Dianthus barbatus

    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
  • Double Mixture105–112 days

    Non-GMO; Container; Annual; Biennial

    105-112 days to maturity. Dianthus barbatus. Dianthus Double Mixture Seeds. Non-GMO, Annual, or Biennial. Ornamental. Double Mix Sweet William seeds promise elegant 3-5 inch blooms of crimsons, scarlets, and pinks to invigorate your home or garden. Sweet William Double Mix seeds are easy to grow, tolerant, and mature into brilliant, fragrant blooms irresistible to hummingbirds, butterflies and bees. Double Mix Sweet William seeds grow sweet, herbal flowers commonly used in the kitchen to accent jams, fish, or Mediterranean dishes. Sweet William Double Mix seeds can grow as perennials in optimal climates, but thrive as hardy biennials in most gardens. About 25,000 seeds per ounce.

    View on True Leaf Market
  • Wee Willie105–112 days

    Non-GMO; Container; Annual; Biennial

    105-112 days to maturity. Dianthus barbatus. Dianthus Wee Willie Seeds. Non-GMO, Annual, or Biennial. Ornamental. Wee Willie Sweet William seeds are an adorable, compact, and vibrant addition to grow in any home or garden. Sweet William Wee Willie seeds are durable and easy to grow, ideal for indoor pots, planters, window boxes, or for a charming border around the flower bed. Wee Willie Sweet Williams are the smallest and one of the most unique varieties of Sweet William, perfect to decorate indoors, give as a potted gift, or keep the butterflies fluttering around the garden. Wee Willie seeds are hardy, tolerant, and ideal for gardens prone to heat and drought. About 25,000 seeds per ounce.

    View on True Leaf Market
Family
Caryophyllaceae
Category
Flower
Form
Stalk
Lifecycle
annual or biennial
Zone
3-9
Height
0.25–2 ft
Spread
0.5–1 ft
Sun
Full sun

Plant spacing

1 plant per square footSquare-foot planting diagram: one sweet william fills a 1-foot square, spaced 12 inches from its neighbors.
1 plant per square foot

In a square-foot bed, space sweet william about 12 in apart — that fits 1 plant in each 1-foot square (1×1). Wider rows or containers space the same.

Water
Dry to medium

Plan your sweet william planting

Add sweet william 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
100–112 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
Hardy · to ~15°F
Lowest temperature the foliage usually survives

Growing timeline

When to plant and harvest sweet williamPlanting timeline for sweet william, relative to last frost: grow from 1 week after last frost to 15 weeks after last frost; harvest from 15 weeks after last frost to 17 weeks after last frost.GrowHarvestLast frostDirect sow
Direct-sow sweet william 1 week after last frost; first harvest 15 weeks after last frost.
Outdoor planting
7 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.

Pairs well with (2)

  • CornEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationstructural-support, pollinator-attract

    Sunflowers planted in or near corn rows provide structural niches for pole beans and feed pollinators and seed-eating birds; not a documented yield benefit but a common Midwest home-garden practice.

    Source: S8

  • Squash (Cucurbita spp., generic)Evidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, structural-support

    Sunflowers attract native bees that pollinate squash; vines occasionally use lower sunflower stems as support. Manage spacing to prevent shading.

    Source: S8

Avoid planting near (3)

  • Common BeanEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismallelopathy-negative

    Helianthus annuus produces allelopathic terpenes (chlorogenic and isochlorogenic acids, sesquiterpene lactones) released by roots and decomposing residues that inhibit germination and growth of bean, potato, and several small-seeded vegetables. Documented in peer-reviewed allelopathy literature and Northern Plains extension trials.

    Timing: Avoid direct seeding small-seeded crops within 1 m of sunflower row, and into ground freshly cleared of sunflower residue.

    Source: S22, Putnam, 1988

  • Common PotatoEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismallelopathy-negative

    Field studies (USDA-ARS, Northern Plains) show sunflower residues reduce potato emergence and tuber growth when planted into recently sunflower-cropped soil.

    Timing: Allow at least one season between sunflower and potato.

    Region: Northern Plains, Saskatchewan.

    Source: USDA ARS, S22

  • Common ArtichokeEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host

    Globe artichoke is susceptible to Sclerotinia and Verticillium that also infect sunflower; UC IPM advises against following sunflower in artichoke ground.

    Region: California production.

    Source: UC IPM

Sources cited

S20
USDA ARS (Agricultural Research Service) publications
S22
University of Saskatchewan / Saskatchewan Ministry of Agriculture
S3
UC IPM (University of California Agriculture and Natural Resources)
S33
Putnam, 1988 — cereal rye allelopathy review
S8
Iowa State University Extension and Outreach

Care & troubleshooting— extension-sourced, with citations

When to feed, prune & water

Harden off seedlings

Protection

Unusual this time of year.

Read: starting seeds indoors

Something looks wrong?

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

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

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

Spider mites

Pestmoderate

Symptoms: fine pale stippling/speckling on leaves; fine webbing on undersides in hot dry spells; leaves bronzing and dropping

  • CulturalHose down and raise humidity· every 3 days · ~2 wksstrong evidence — extension confidence

    Mites thrive in hot, dry, dusty conditions. Spray foliage (especially undersides) with water to dislodge them and reduce dust.

    Source: UC IPM

  • OrganicInsecticidal soap or horticultural oil - label use only· every 5 days · ~2 wksmoderate evidence — extension confidence

    Apply to undersides per label; mites resist many products, so soaps/oils are preferred. Not in extreme heat.

    Always follow the product label — it is the law.

    Source: UC IPM

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

Leaf miners

Pestlow

Symptoms: winding pale tunnels inside the leaf; pale blotches between the upper and lower leaf surfaces; tunnels/blotches that can't be rubbed off because the larva is inside

  • CulturalPick mined leaves + row cover· every 5 days · ~3 wksmoderate evidence — extension confidence

    Remove and bag leaves with tunnels, and cover plants with insect netting to block the egg-laying flies. Damage is mostly cosmetic on leafy crops.

    Source: UMN Extension