How to Grow Sweetclover

Sweetclover

Melilotus officinalis

herb

Sweetclover is a biennial legume with fragrant yellow or white flowers that bloom in tall spikes. It is widely used as a cover crop, green manure, and forage plant due to its nitrogen-fixing abilities and aromatic properties. The plant has a distinctive sweet vanilla-like scent, especially when dried.

Looking for a specific variety?

Yellow Sweetclover White Sweetclover Emerald Madrid Denta

When should you plant Sweetclover in your zone?

Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.

Get my Sweetclover timeline →

Example Sweetclover timeline · Pittsburgh, PA (Zone 6b)

Plant Sweetclover
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Sweetclover
Late summer into fall

Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Sweetclover dates for your own zip code.

Growing Conditions

☀️

Sun: Full sun, 6-8 hours daily; tolerates partial shade

💧

Water: Moderate water needs; drought-tolerant once established. Water seedlings regularly until established; mature plants require minimal supplemental watering

📏

Spacing: 6-12 inches between plants; can be direct seeded at 15-20 lbs/acre inches

📅

Days to maturity: First year: rosette stage; Second year: 80-120 days to flower and seed production

🌱

Planting depth: 1/4 to 1/2 inch; light coverage preferred

Soil

Type: Well-draining loamy or sandy soil; tolerates poor soil conditions

pH: 6.0-7.5

Amendments:

Inoculant with Rhizobium bacteria to enhance nitrogen fixation Lime if soil is acidic (below pH 6.0) Minimal fertilizer needed due to nitrogen-fixing abilities

Growing Zones

Find your zone →

Thrives in zones 2-8; highly cold-hardy and drought-tolerant

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b

Get my Sweetclover timeline →

Growth Stages

Germination & Seedling

2-3 weeks

Seeds germinate in 7-14 days with adequate moisture. Seedlings develop true leaves and establish a taproot system

Scarify seeds lightly or soak in water for 24 hours to improve germination. Keep soil consistently moist but not waterlogged. Thin seedlings to proper spacing

First Year Rosette (Biennial)

6-8 months

Plant develops basal rosette of pinnate leaves close to the ground. No flowers appear in the first year as the plant accumulates energy

Allow the plant to overwinter; cold exposure triggers flowering in spring. Remove weeds to reduce competition. No special feeding required

Vegetative Growth (Second Year Spring)

4-6 weeks

Rapid stem elongation occurs in spring, with compound leaves developing along tall, branching stems reaching 3-6 feet tall

Stems may become tall and require staking in windy areas. Water during drought to support vigorous growth. Monitor for aphids and other early-season pests

Flowering & Pollination

4-8 weeks

Dense racemes of small, fragrant flowers appear, typically yellow (M. officinalis) or white (M. alba). Flowers attract bees and other pollinators

Do not disturb during flowering to ensure good pollination and seed set. Flowers emit strong sweet scent, especially when warm. Deadhead if preventing self-seeding

Seed Maturation & Harvest

3-4 weeks

Flowers fade and develop into small pod-like fruits containing seeds. Pods dry on the plant and turn brown, becoming brittle

Harvest pods when fully dry and brown. Allow plants to fully mature and dry before cutting for maximum seed viability. Collect seed heads and thresh to collect seeds

Companion Planting

Plan your garden →

Plant with:

Grasses (timothy, orchardgrass, bromegrass) for pasture/hay mixtures Alfalfa for diversified nitrogen-fixing cover crop mix Cereal grains (wheat, barley, oats) for rotation Root vegetables (turnips, rutabagas) that benefit from improved soil Brassicas that use nitrogen provided by the cover crop

Avoid planting near:

Plants requiring low-nitrogen soil conditions Livestock or wildlife that may overgraze before flowering (if seed production is desired) Solanaceae (tomatoes, peppers, eggplants) in immediate vicinity

Common Pests

Plant resistant varieties; rotate crops; clip plants if heavy feeding occurs; natural predators usually control populations
Spray with water to dislodge; use insecticidal soap; encourage natural predators like ladybugs and parasitic wasps
Spray with water; ensure adequate moisture in soil; apply neem oil if severe
Monitor for population buildup; use row covers on seedlings; natural predators usually manage populations

Uses

🍳

Herbal tea & flavoring

Culinary

Sweetclover flowers and dried leaves produce a pleasant, vanilla-scented herbal tea with a naturally sweet flavor. The plant is also used to flavor beverages and impart a distinctive sweet note to hay used for livestock. [source]

💊

Traditional anti-inflammatory remedy

Medicinal

Historically used in herbal medicine to support lymphatic drainage and reduce swelling. Contains coumarin compounds that have been studied for anti-inflammatory and anticoagulant properties. [source]

🏠

Natural perfume & moth repellent

Household

Dried sweetclover flowers and leaves are traditionally placed in closets, drawers, and sachets to repel moths and insects while imparting a pleasant sweet fragrance. Fresh dried bundles freshen rooms naturally. [source]

🎨

Dried flower arrangements & craft material

Craft

The tall stems with dried flower spikes are valued by florists and craft enthusiasts for dried arrangements, wreaths, and decorative projects. The delicate appearance and sweet fragrance persist long after drying. [source]

🦋

Pollinator forage & livestock feed

Wildlife

Sweetclover is an excellent nectar and pollen source for bees, butterflies, and other pollinators throughout its flowering season. It is widely grown as a cover crop and forage plant because it fixes atmospheric nitrogen and improves soil fertility while providing nutritious feed for cattle, sheep, and horses. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

For seed production: Allow plants to complete their second-year cycle and fully mature. Harvest seed heads when pods are completely dry and brown, typically mid- to late summer. Cut stems at base, bundle, and thresh to release seeds. For fresh use: Harvest leaves and flowers at any stage before seed maturity for culinary or medicinal applications. For cover crop/green manure: Till under in late fall or early spring before or during flowering stage for maximum nitrogen contribution to soil.

Fun Facts

🌱 Sweetclover can fix up to 150 lbs of nitrogen per acre annually through its symbiotic relationship with Rhizobium bacteria, making it one of the most valuable cover crops for sustainable agriculture.
🌱 The plant's distinctive sweet vanilla scent intensifies when the plant is dried, which is why it was historically used to stuff mattresses and freshen homes before the advent of commercial air fresheners.
🌱 Sweetclover has been cultivated for over 2,000 years and was brought to North America by European settlers; it is now naturalized across much of the continent.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Biennial Cover Crop Deadhead Full Sun Germination Green Manure Partial Shade pH Pollination True Leaves

Shop Sweetclover plants and related plants at Plant Addicts →

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized Sweetclover planting timeline

Tell us your zip code and we'll calculate exactly when to start Sweetclover seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.

Get my Sweetclover timeline →