Illustration
Royal White Sweet Pea
Lathyrus odoratus
Royal White Sweet Pea blooms from May through July.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Royal White Sweet Pea
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 2–11. Expect it to reach about 6 ft tall and 1.5 ft wide at maturity, in roughly 1 year (not yet checked).
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. 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 Royal White Sweet Pea
Wait until all danger of frost has passed, then plant out Royal White Sweet Pea into warm soil; in most zones that means late spring. Planted then, it flowers from May to July.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Royal White Sweet Pea get?
6 fttall5 ft 7 inan adult1.5 ftwideSee Royal White Sweet Pea 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 Royal White Sweet Pea
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Royal White Sweet Pea about 1.5 ft apart, center to center, so each plant has room to reach its full width.
Add Royal White Sweet Pea 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
Royal White Sweet Pea's height, spread, hardiness zones, sun and trait tags were checked against 7 published sources on July 29, 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 GardenPlant Finderheight, spread, hardiness zones, sun and trait tags
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun and trait tags
- American MeadowsRoyal Family Sweet Pea Seeds Mixheight, hardiness zones, sun and trait tags
- edenbrothers.comEden Brothers (Sweet Pea Seeds - Royal Mix)height and trait tags
- Johnny's Selected SeedsRoyal Wedding Sweet Peaheight and trait tags
- University of Illinois Extensionheight and trait tags
- University of Georgia ExtensionBulletin 954 Flowering Annuals for Georgia Gardenstrait tags
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Royal White Sweet Pea
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
The seeds and pods are poisonous: do not eat them, and do not confuse this with the edible garden pea it resembles. Keep seeds from children and pets. per NC State and Missouri Botanical Garden
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.