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When to plant Black-eyed Susan in St. Helena Parish County,

Spring Black-eyed Susan in St. Helena Parish County goes in February 19–March 12, once nighttime temps stop dipping near freezing.

When to Plant Black-eyed Susan in St. Helena Parish, LA

St. Helena Parish, Louisiana Zone 9a June

June in St. Helena Parish, Louisiana — your action list

Each item below is timed to St. Helena Parish, Louisiana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 5
Avg. first frost November 30
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Harvest black-eyed susan as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Coming up in July — start thinking about
  • First harvests: black-eyed susan

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Rudbeckia hirta (Black-eyed Susan) is one of the most recognizable and adaptable native wildflowers in North America. Its bright golden-yellow daisy petals radiate from a dark brown central cone, providing months of color from midsummer into fall. Technically a short-lived perennial that self-seeds freely — colonies persist indefinitely in the garden — it thrives in poor soils, tolerates drought, and is irresistible to bees, butterflies, and goldfinches.

St. Helena Parish, Louisiana is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 30, giving you a growing season of approximately 270 days.

At an elevation of 437 feet, St. Helena Parish receives approximately 50 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Black-eyed Susan may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Black-eyed Susan will need more frequent watering and organic matter to retain nutrients.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
St. Helena Parish, LA (Zone 9a) Year-round
270 days
Last Spring Frost March 5
270 growing days
First Fall Frost November 30
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St. Helena Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.5

Drainage

Well Drained

Black-eyed Susan Planting Risk Windows

Early Start (70% safe) ✓ Fits season (82 days to spare)
Start indoors: Dec 21 Transplant: Feb 1 🌸 Bloom: Apr 12 – Aug 30
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Jan 8 Transplant: Feb 19 🌸 Bloom: Apr 30 – Sep 17
Safe Start (90%) ✓ Fits season (68 days to spare)
Start indoors: Jan 29 Transplant: Mar 12 🌸 Bloom: May 21 – Oct 8

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in St. Helena Parish

How your county's soil matches Black-eyed Susan's growing requirements.

Soil pH

Your soil pH (4.8–6.5) is more acidic than Black-eyed Susan prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Helena Parish warms quickly in spring but drains fast. Black-eyed Susan will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.7%). Add 2-3 inches of compost before planting Black-eyed Susan.

How to Plant Black-eyed Susan

18"
Between Plants
24"
Between Rows

Succession Planting Black-eyed Susan

5
successive plantings in your 270-day season

Sow every 6.9 weeks. Last sowing by Sep 11 to harvest before frost.

Black-eyed Susan Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Black-eyed Susan

Black-eyed Susan needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Black-eyed Susan Needs Rainfall You Supplement Action
Jan 3.8" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 2.2" 5.5" 0" ✅ Rainfall sufficient
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 4.7" 0" ✅ Rainfall sufficient
Aug 2.2" 5.1" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.3" 0" ✅ Rainfall sufficient
Nov 2.2" 4.4" 0" ✅ Rainfall sufficient
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in St. Helena Parish). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Black-eyed Susan Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Black-eyed Susan needs ~1,540 GDD — county provides 5,940 GDD Excellent fit

Black-eyed Susan Planting Timeline — St. Helena Parish, LA

Black-eyed Susan Planting Calendar

Activity When Date Range
Start Indoors January 8 Jan 8 – Jan 22
Transplant Outdoors February 19 Feb 19 – Mar 5
Direct Sow February 19 Feb 19 – Mar 12
Bloom April 30 Apr 30 – Sep 17

· 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

270 days in St. Helena Parish

Growing Tips for Black-eyed Susan in St. Helena Parish

Direct sow Black-eyed Susan outdoors after March 05 in St. Helena Parish when soil has warmed and frost danger has passed.

Sandy soil in St. Helena Parish dries quickly — mulch Black-eyed Susan with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96°F in St. Helena Parish, provide afternoon shade for Black-eyed Susan and water deeply in the morning.

Common pests for Black-eyed Susan in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8–10 weeks before last frost or direct-sow after last frost (needs light to germinate — press seeds onto soil surface, do not cover). Thrives in average to poor soil; rich soil causes floppy stems. Deadhead for extended bloom but leave some seed heads for winter wildlife interest and self-seeding. Although technically short-lived (3–5 years), prolific self-seeding maintains the colony. Year 2+ plants bloom most heavily. Divide every 3 years to maintain vigor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Black-eyed Susan in St. Helena Parish, LA?

St. Helena Parish is in Zone 9a with an average last frost of March 5. Plan your Black-eyed Susan planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Helena Parish, LA?

St. Helena Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 30.

When should I plant Black-eyed Susan in St. Helena Parish County, ?

In St. Helena Parish County, , plant Black-eyed Susan after the last frost (around March 5) and before the first frost (around November 30). Best results when soil holds above 50°F.

What growing zone is St. Helena Parish County, for Black-eyed Susan?

St. Helena Parish County sits in USDA Zone 9a. Black-eyed Susan grows reliably in zones 3a through 9b, so it's a good fit here.

Can Black-eyed Susan grow in St. Helena Parish County's climate?

Yes — Black-eyed Susan grows well in St. Helena Parish County's temperate climate. St. Helena Parish County averages a 270-day frost-free season, with last frost around March 5 and first frost around November 30.

🌱

Your St. Helena Parish Garden Planner — Free

A 22-page printable planner built for St. Helena Parish (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for St. Helena Parish, LA. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.