Sweet Pea Knee High Mix bushy plants in bloom

How to Grow Sweet Pea Knee High Mix From Seed

By Maxim Kaufman — Founder & CEO, Organo Republic

Updated July 2026

Sweet Pea Knee High Mix is the perfect middle ground between towering climbers and tiny dwarfs. As the name suggests, these plants grow to roughly two to three feet, forming self-supporting bushes that stand up with only light support. What sets Knee High apart is the flowers: it produces large, richly fragrant blooms in a beautiful range of colors, on stems long enough for excellent cutting. If you want a generous, scented cut-flower patch without building a big trellis, Knee High Mix is a wonderful choice.

This is the quick guide to Sweet Pea Knee High Mix. For the full step-by-step on soaking seed, sowing, feeding, and troubleshooting, see our complete guide to growing sweet peas from seed.

Quick start

Soak the seeds for 12 to 24 hours (or nick the coat), then sow them about one inch deep and two to three inches apart in full sun and rich, well-drained soil. Sow in very early spring as soon as the soil can be worked, or in fall in mild-winter zones. Knee High grows to about two to three feet in a self-supporting bush, so give it only light support like short twiggy stakes or a low net. Pinch the tips early, keep the soil evenly moist, and begin cutting large, fragrant stems in roughly 80 to 95 days.

Best tip

Give Knee High light support and cut it often. Even though Knee High is self-supporting, a few short twiggy stakes or a low net keeps the bushes upright and the flowers clean, especially after rain. Harvest stems every couple of days when the lowest blooms open; constant cutting keeps the large, fragrant flowers coming. In hot regions, sow as early as the soil can be worked so the plants bloom well before summer heat shuts them down.

At a glance

Botanical nameLathyrus odoratus 'Knee High Mix'
Plant typeAnnual flower (bush type)
USDA zones2 to 11 (grown as a cool-season annual)
SunFull sun (afternoon shade in hot climates)
Days to maturityBlooms in about 80 to 95 days from sowing
Height2 to 3 ft
Spacing2 to 3 in apart
WaterKeep consistently moist; water deeply

Uses

Knee High Mix is a cut-flower gardener's favorite. Its bushy, knee-high plants produce large, strongly scented blooms on good stems, making it ideal for a dedicated cutting patch, mixed borders, and larger containers or raised beds. Because it needs only light support it fits easily into a flower bed without a big structure, yet it still gives you armloads of fragrant stems for bouquets. As with every sweet pea, remember it is an ornamental flower only: enjoy the blooms and scent, but never eat the seeds or pods, which are poisonous.

Frequently asked questions

How tall does Sweet Pea Knee High Mix grow?

Knee High Mix grows to about two to three feet tall, forming a self-supporting bush. It is taller than dwarf Bijou types but much shorter than the three-to-six-foot climbing sweet peas.

Does Knee High Mix need support?

Only light support. The plants largely hold themselves up, but a few short twiggy stakes or a low net keep the bushes tidy and the flowers clean, especially in wind or after rain.

Is Knee High Mix good for cut flowers?

Yes. Knee High produces large, strongly fragrant blooms on good stems, so it is an excellent choice for a cutting garden and bouquets while staying compact enough for borders and raised beds.

Are Sweet Pea Knee High Mix seeds safe to eat?

No. All sweet peas, including Knee High Mix, are ornamental flowers only. The seeds and pea-like pods are poisonous if eaten, so grow this plant for its flowers and fragrance and keep it away from children and pets.

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Maxim Kaufman, Founder and CEO of Organo Republic

By Maxim Kaufman — Founder & CEO, Organo Republic

Maxim founded Organo Republic in 2017 and personally selects, tests, and grows the heirloom, non-GMO varieties the company offers. Under his leadership, Organo Republic was named Agri Business Review’s Top Non-GMO Seed Variety Solution 2026.