Heirloom

Green Gold

Bupleurum rotundifolium

Photo: Wojciech K. · Wikimedia Commons · (CC BY-SA 4.0)

Upright plants produce 2 1/2" yellow-lime green flowers atop long, wiry stems. Excellent for mixed bouquets and makes a unique dried flower. Also known as thoroughwax and hare's ear. Also available in organic seed.

Harvest

80-90d

Days to harvest

📅

Sun

Full sun

☀️

Zones

5–9

USDA hardiness

🗺️

Height

16-24 inches

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Start Indoors

Transplant

Direct Sow

Start Indoors

Transplant

Direct Sow

Showing dates for Green Gold in USDA Zone 7

All Zone 7 flower →

Zone Map

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Green Gold · Zones 5–9

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing12-18 inches

SoilWell-drained soil

WaterModerate; water when soil surface dries

SeasonWarm season annual

Coloryellow-lime green

Size2 1/2"

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 3	April – May	June – July	June – August	—
Zone 4	March – April	June – June	June – July	—
Zone 5	March – April	May – June	May – July	—
Zone 6	March – April	May – June	May – July	—
Zone 7	February – March	April – May	April – June	—
Zone 8	February – March	April – May	April – June	—
Zone 9	January – February	March – April	March – May	—
Zone 10	January – January	February – March	February – April	—
Zone 1	May – June	July – August	July – September	—
Zone 2	April – May	June – July	June – August	—
Zone 11	January – January	January – February	January – March	—
Zone 12	January – January	January – February	January – March	—
Zone 13	January – January	January – February	January – March	—

Succession Planting

Bupleurum makes a good succession crop for cut-flower production. Start indoors in late February to early March, then direct sow every 3 weeks from April 1 through mid-May in zone 7 — that gives you a staggered harvest across roughly 8–10 weeks rather than one flush. Stop spring sowings when daytime highs are consistently hitting 85°F, because plants started in that heat bolt fast and give you maybe a week of cuttable stems.

Pick back up with a fall round: direct sow in late August or early September for harvest in late October through November. Days to harvest run 80–90, so count backward from your first average frost date (early November in much of zone 7) and sow accordingly. That fall planting often produces the cleanest, straightest stems of the year — cooler nights slow the plants down just enough.

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day). Soil: Loam (Silt), Sand. Soil pH: Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist, Occasionally Dry. Height: 1 ft. 4 in. - 2 ft. 0 in.. Spread: 1 ft. 0 in. - 1 ft. 4 in.. Spacing: 12 inches-3 feet. Growth rate: Rapid. Maintenance: Low. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.

Harvesting

Oblong fruit are tiny and do not open when ripe.

Color: Black. Length: < 1 inch. Width: < 1 inch.

Harvest time: Fall, Summer

Edibility: Leaves can be eaten.

Storage & Preservation

For fresh flowers, store Green Gold upright in a vase with cool water (65-72°F) in a cool location away from direct sunlight and ethylene-producing fruits. Change water every 2-3 days; they'll last 7-10 days fresh. For drying, harvest stems when flowers are fully open, remove lower foliage, and hang upside-down in a warm, dark, well-ventilated space (70-75°F, 40-50% humidity) for 2-3 weeks. Dried flowers remain vibrant for 6-12 months stored in a cool, dry place. Alternatively, press flowers between parchment paper under weight for 2-3 weeks, or preserve in glycerin solution for a more pliable dried arrangement option.

History & Origin

Origin: Central and southern Europe, Asia

Advantages

+Edible: Leaves can be eaten.
+Fast-growing
+Low maintenance

Companion Plants

Marigolds and sweet alyssum are the two worth prioritizing near Bupleurum. French marigolds (Tagetes patula) emit thiophenes from their roots that suppress soil nematodes, and their scent confuses aphids mid-flight. Sweet alyssum draws in parasitic wasps and hoverflies — both prey on aphids and small caterpillars — and it stays low enough that it won't compete for the 16–24 inches of vertical space Bupleurum needs. Nasturtiums pull double duty as a trap crop for black aphids; plant them at the bed edge and let them take the hit so your Bupleurum stems stay clean for harvest.

Black walnut is the one to keep far off the planting list. It produces juglone, a compound toxic to a wide range of plants, and the root zone extends well beyond the canopy drip line — a real problem in our zone 7 Georgia gardens where old walnut trees often border vegetable and cut-flower beds. Sunflowers are worth avoiding too: they release allelopathic compounds from their roots and from decomposing tissue that can suppress germination and stunt neighboring annuals, which matters if you're rotating Bupleurum through the same beds season to season.

Plant Together

Marigolds

Repel nematodes, aphids, and whiteflies while attracting beneficial insects

Nasturtiums

Act as trap crops for aphids and cucumber beetles, deterring pests from main plant

Lavender

Repels moths, fleas, and mosquitoes while attracting pollinators like bees and butterflies

Sweet Alyssum

Attracts beneficial insects like lacewings and hoverflies that control aphids

Chives

Repel aphids, Japanese beetles, and carrot flies with their strong sulfur compounds

Yarrow

Improves soil health and attracts predatory wasps and ladybugs for pest control

Cosmos

Attract beneficial insects including parasitic wasps and provide habitat for predators

Borage

Attracts pollinators and beneficial insects while potentially improving plant vigor

Keep Apart

Black Walnut

Produces juglone compound that is toxic to many flowering plants and inhibits growth

Eucalyptus

Releases allelopathic compounds that suppress growth of nearby plants

Sunflowers

Can release allelopathic chemicals and compete aggressively for nutrients and water

Troubleshooting Green Gold

What you'll see, why it happens, and what to do about it.

Seedlings damping off at soil level — stem pinches thin, plant collapses — within the first 2 weeks of germination

Likely Causes

Pythium or Rhizoctonia fungi in soggy seed-starting mix
Overwatering combined with poor airflow around seedling trays

What to Do

1.Water only when the top of the mix is dry to the touch; Bupleurum doesn't want wet feet at any stage
2.Run a small fan on low near your trays to keep air moving
3.If you're starting indoors in February or March, use a fresh, sterile seed-starting mix — don't reuse last year's

Powdery white coating on leaves and stems, usually showing up mid-summer after plants have been in the ground 50-60 days

Likely Causes

Powdery mildew (Erysiphe or Golovinomyces spp.) — favored by warm days, cool nights, and low airflow
Crowded spacing under 12 inches that traps humidity around foliage

What to Do

1.Space plants at least 12 inches apart — 15 is better if you're in a humid spot
2.Apply a diluted baking soda spray (1 tablespoon per gallon of water) at first sign, or use a sulfur-based fungicide labeled for ornamentals
3.Pull and bin any heavily infected stems; don't compost them

Plants bolt and go fully to seed weeks earlier than expected, cutting the harvest window short

Likely Causes

Heat stress — Bupleurum rotundifolium flags when daytime highs hold above 85–90°F for more than a few days running
Direct sowing too late in spring, pushing plants into peak summer heat before they've put on enough stem length to cut

What to Do

1.In zone 7, make your last direct sowing by mid-May; anything sown in June will likely run short on usable stems
2.Time a second planting for late August to early September for a fall cut-flower flush before frost
3.Hang 30% shade cloth over young plants if a heat wave hits before they've reached 12 inches tall

Frequently Asked Questions

How long do Green Gold flowers last in a vase?▼

Green Gold flowers typically last 7-10 days in a vase when kept in cool water (65-72°F) with regular water changes every 2-3 days. They're particularly valued because they dry beautifully while maintaining their unique yellow-lime green color, extending their lifespan indefinitely as dried flowers for arrangements and crafts.

Is Green Gold easy to grow for beginners?▼

Yes, Green Gold is rated as easy to grow, making it perfect for beginners. It requires full sun (6+ hours daily), well-drained soil, and minimal maintenance once established. The plants are hardy and forgiving, producing abundant flowers on upright stems ideal for cutting within 80-90 days from planting.

Can you grow Green Gold in containers?▼

Yes, Green Gold can be grown in containers, though they perform best with adequate depth for root development and good drainage. Container growing works well for controlled environments and allows you to position plants in optimal full-sun locations. Use quality potting soil and water consistently to keep soil evenly moist.

When should I plant Green Gold?▼

Plant Green Gold after the last frost date in your area, as it prefers warm soil and sunlight. Direct sow seeds outdoors or start indoors 6-8 weeks before your last spring frost. With 80-90 days to harvest, planting in spring ensures flowering throughout summer and into fall for cutting and drying.

What makes Green Gold unique as a dried flower?▼

Green Gold stands out because its distinctive yellow-lime green flowers maintain their vibrant color and delicate form beautifully when dried. Unlike many flowers that fade, the dried blooms retain their unique hue for 6-12 months, making them excellent for long-lasting arrangements, wreaths, and craft projects.

What is the best method to dry Green Gold flowers?▼

Hang-drying is the preferred method for preserving Green Gold's color and form. Cut flowers when fully open, remove lower foliage, and bundle loosely with twine. Hang upside-down in a warm (70-75°F), dark, well-ventilated space for 2-3 weeks. This method preserves the flowers' delicate stems and vibrant yellow-lime coloring.