"Leave those roots in the ground," my neighbor said over the fence, waving at my spent Old Spice sweet peas. "They'll come right back next year, you wait." So I left them. Come spring, the back fence stood bare. Whether your sweet pea comes back depends on the species, and the answer splits into two plants. A true sweet pea perennial returns each year, but the fragrant climber most people grow does not.
The scented vine you picture is the annual sweet pea, known to botanists as Lathyrus odoratus. It runs through one full life in a single season. The plant sprouts, climbs, blooms, sets seed pods, and then dies once the heat arrives. No matter how healthy those roots look in fall, they will not push out new growth the following spring. I learned that the bare way, staring at my own empty trellis.
That short life is just how the plant is built, so it is not a sign you did anything wrong. The annual sweet pea traces back to southern Italy, Sicily, and Crete. There it grows fast through the cool months and finishes before summer turns harsh. You replant it from seed every year to keep that famous scent coming back along your fence or trellis. Think of it like a tomato. You love it, you grow it, and you start fresh each season.
Why does it die when the roots still look fine? The plant pours all its energy into seed by the end of the season. Once those pods form and dry, the vine has done its only job and shuts down. You cannot coax a second year out of it, no matter how well you water or feed the soil. That is the trade you accept for the strongest scent in the garden.
The plant my neighbor had in mind is a different species that truly does return. Here is the simple split between the two so you can tell them apart.
- Lives one cool season, then dies for good.
- Carries the strong, sweet scent people prize.
- Must be replanted from seed each year.
- Regrows yearly from its established roots.
- Has almost no scent at all.
- Spreads fast and can take over a bed.
The vine that comes back on its own is the true sweet pea perennial, sold as Lathyrus latifolius. Its roots survive winter underground and send up fresh shoots every spring. You plant it once and it keeps returning, year after year. The trade-off is scent. This species smells faint to nearly nothing, which surprises people who hoped for that classic perfume drifting across the yard.
Lathyrus latifolius also grows with real force once it settles in. It can spread fast through your bed and crowd out smaller plants. Give it room and a sturdy support, and keep it away from anything delicate you want to protect. Plenty of gardeners still love it. It covers a slope or a long fence with little fuss, and the pink and white flowers look bright even without a smell. If you want a vine you never replant, this is your plant.
Before you count on any sweet pea returning, check the species name or the seed packet. The name does all the work here. If it says Lathyrus odoratus, treat it as a one-season plant and sow fresh seed each cool season. If it says Lathyrus latifolius, plant it once and let those roots take over the job for you. Knowing which one sits in your soil saves you a bare fence and a spring spent wondering what went wrong. Match the plant to what you want, and you get the right result every time.
Read the full article: Sweet Pea Vine: Complete Grow Guide
