Garden Scheme

Plant library  ·  Annual Flowers

Sweet Pea

Lathyrus odoratus

Sweet pea is a fragrant annual vine that brings a tall but narrow vertical layer to the garden. Growing to about 6 feet tall and roughly 1 foot wide, it earns its space on a trellis rather than across the bed. Its late-spring to early-summer flowers make it especially useful where a border, fence line, or cutting area needs an early-season lift.

  • Pollinator friendly
  • Deer resistant
Sunlight Full Sun
Water Regular
USDA zones 2–11
Spacing 0.5 ft
Mature size 6 ft tall, 1 ft wide
Bloom Late spring - early summer

Placement and use

Place sweet pea at the back of a border or along a fence, wall, or dedicated trellis where its stems can climb without leaning into lower plants. Install the support before planting, and keep the planting strip close enough to a path for frequent flower cutting and removal of spent blooms. It also suits a cutting garden, where its seasonal display can be managed separately from permanent bed structure.[1][2][3]

Spacing and mature footprint

Set plants 6 inches apart, center to center, to form a closely planted climbing row. Although each plant has a mature width of about 1 foot, the stems can be trained upward and gathered onto a narrow support, keeping the bed edge more open than the eventual foliage spread suggests. Allow clear access on at least one side of the row for tying in stems and cutting flowers.

Three plants set 0.5 ft apart, center to center; shaded circles show the 1 ft mature spread.

Sun, water, and soil

Use a full-sun position with fertile, well-drained soil that does not dry out quickly. Regular moisture is most practical in a bed within easy hose reach or on drip irrigation, particularly when plants are climbing densely on a support. Avoid sites that remain soggy after rain or are shaded for much of the day, since flowering is reduced in shade.[1][2][4]

Seasonal notes

Treat sweet pea as a cool-weather annual and reserve its support for a seasonal display rather than a permanent screen. Blooms arrive from late spring into early summer, then heat can shorten the display. Pick flowers regularly and remove spent blooms to keep the vine producing; plan a later-season replacement for the same trellis if the structure must carry visual weight through summer.[1][3][4]

Growing facts

Botanical name
Lathyrus odoratus
Type
Vine
Category
Annual Flowers
Lifecycle
annual
USDA hardiness zones
2–11
Sunlight
Full Sun
Water
Regular
Plant spacing
0.5 ft
Mature size
6 ft tall, 1 ft wide
Bloom season
Late spring - early summer
Pollinator friendly
Yes
Deer resistant
Yes
Native to North America
No

References

  1. Sweet Pea - Lathyrus odoratus — North Carolina Extension Gardener Plant Toolbox
  2. Sweet peas (annuals) — Royal Horticultural Society
  3. Sweet Pea — Illinois Extension
  4. Sweet Pea, Annual - Hort Answers — Illinois Extension

Editorial content updated 2026-07-20.