Sweet William
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 ↗
Plant spacing
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.
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
Growing timeline
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.
- 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
ProtectionUnusual this time of year.
- Routine careGradually expose plants to the outdoors· every 1 days · ~2 wksstrong evidence — extension confidence
Starting about two weeks before transplanting, set seedlings outside in a sheltered, shady spot for a few hours and lengthen their time and sun exposure each day, avoiding windy days, to prevent transplant shock.
- Routine careEase back on water and transplant on a mild daystrong evidence — extension confidence
Water a little less during hardening (without letting plants wilt) to toughen growth, then transplant in late afternoon or on a cool, cloudy, calm day.
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- 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.
- 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.
Root rot from overwatering / poor drainage
Diseasemoderate- CulturalLet soil drain and water lessstrong evidence — extension confidence
Water root rots like Pythium thrive in saturated soil, so cut back watering, let the surface dry between irrigations, and water at the base rather than keeping soil constantly wet.
- CulturalImprove drainage and aerationstrong evidence — extension confidence
Use raised beds, loosen compacted soil, and add organic matter to improve drainage; remove plants that are already rotted since affected roots won't recover.
Spider mites
Pestmoderate- 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.
- 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.
Aphids
Pestlow- 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.
- 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.
Leaf miners
Pestlow- 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.