Illustration
Lavender Sweet Pea
Lathyrus odoratus
Lavender Sweet Pea blooms from May through July.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Lavender 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 2.5 ft wide at maturity, in roughly 1 year (a house reading).
Is Lavender Sweet Pea toxic to dogs or cats?
- Listed as toxic to dogs and cats by Pet Poison Helpline.
- Listed as poisonous to people by NC State Extension.
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 Lavender Sweet Pea
Wait until all danger of frost has passed, then plant out Lavender 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 Lavender Sweet Pea get?
6 fttall5 ft 7 inan adult2.5 ftwideSee Lavender 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 Lavender Sweet Pea
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Lavender Sweet Pea about 2.5 ft apart, center to center, so each plant has room to reach its full width.
Add Lavender 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
Lavender Sweet Pea's height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 8 published sources on October 28, 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
- RHSRoyal Horticultural Societyheight, sun and trait tags
- seedstore.comSeedStorebloom months and color and trait tags
- University of Illinois ExtensionIllinois Extensionheight and water
- blogs.cornell.eduCornell Universitytrait tags
- Chicago Botanic Gardentrait tags
- Iowa State University Extensionand Outreachheight
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Lavender 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.