Illustration
Smooth Solomon's Seal
Polygonatum biflorum
Also called small solomon's seal and seal flower
Also comes in yellow.
Smooth Solomon's Seal blooms from April through May.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Smooth Solomon's Seal
Plant it in part shade. It prefers moderate water. It is hardy in USDA zones 3–8. Expect it to reach about 3.5 ft tall and 2 ft wide at maturity, in roughly 3 years (a house reading).
Is Smooth Solomon's Seal toxic to dogs?
- Listed as toxic to dogs by Royal Horticultural Society.
- Not yet checked for cats.
- Listed as poisonous to people by NC State Extension and Royal Horticultural Society.
Lists differ and none is complete. If a pet eats a plant and seems unwell, call a veterinarian or a pet poison helpline.
What was checked
Nine facts were checked against named botanical sources, each recorded beside the sources that carried it: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Soil, diseases, pests, toxicity and the plant's own names have not yet been read for this plant, and its trait tags are the ones a feature uses rather than every word a page prints. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Smooth Solomon's Seal
Plant Smooth Solomon's Seal in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 5, the middle of its hardy zones 3 to 8, spring means April to June and fall means August or September. Once settled, it blooms from April to May.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 5, the middle of this plant's hardy range, start with zone 5 in April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Smooth Solomon's Seal get?
3.5 fttall5 ft 7 inan adult2 ftwideSee Smooth Solomon's Seal in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Smooth Solomon's Seal
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Smooth Solomon's Seal about 2 ft apart, center to center, so each plant has room to reach its full width.
Add Smooth Solomon's Seal to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Smooth Solomon's Seal's height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 7 published sources on October 22, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- Missouri Botanical Gardenheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
- NC State Extensionheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
- Chicago Botanic Gardenhardiness zones, sun, water, bloom months and color and trait tags
- Prairie Moon Nurseryheight, hardiness zones, water, bloom months and color and trait tags
- University of Wisconsin HorticultureUniversity of Wisconsin-Madison Extensionheight, hardiness zones, sun and bloom months and color
- RHSRoyal Horticultural Societyheight, water and bloom months and color
- University of Illinois Extensionheight, hardiness zones and water
How the checking works, and what each standard covers, is on the verified plants page.
Where it grows wild
Native to 40 states and 4 provinces
United States: Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin, Wyoming and 28 more
Canada: Manitoba, Ontario, Quebec, Saskatchewan
Recorded growing wild in 1,376 counties.
Range data from the World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 4.0, adapted) and USDA PLANTS. How the native range is credited.
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Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.