Blog

When to plant Black-eyed Susan in Pottawattamie County County,

Pottawattamie County County's climate puts the Black-eyed Susan spring window between April 30 and May 21. time plantings around the expected last-frost window for best survival.

When to Plant Black-eyed Susan in Pottawattamie County, IA

Pottawattamie County, Iowa Zone 5b June

June in the garden — Pottawattamie County, Iowa

Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 30
Avg. first frost October 3
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
Before July arrives, get these ready
  • Starting indoors: black-eyed susan
  • First harvests: black-eyed susan

Instant PDF download. No spam, unsubscribe any time.

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.

Pottawattamie County, Iowa is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 3, giving you a growing season of approximately 156 days.

At an elevation of 518 feet, Pottawattamie County receives approximately 33.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Black-eyed Susan during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Pottawattamie County, IA (Zone 5b) Moderate season
156 days
Last Spring Frost April 30
156 growing days
First Fall Frost October 3

Pottawattamie County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Black-eyed Susan Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 19 Transplant: May 7 🌸 Bloom: Jul 23 – Oct 29
Recommended (50%) ✗ May not fit
Start indoors: Feb 26 Transplant: May 14 🌸 Bloom: Jul 30 – Nov 5
Safe Start (90%) ✗ May not fit
Start indoors: Mar 13 Transplant: May 29 🌸 Bloom: Aug 14 – Nov 20

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 Pottawattamie County

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

Soil pH

Your soil pH (6.1–6.9) is within Black-eyed Susan's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Pottawattamie County is excellent for Black-eyed Susan — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.0%) — Black-eyed Susan will thrive.

How to Plant Black-eyed Susan

18"
Between Plants
24"
Between Rows

Succession Planting Black-eyed Susan

3
successive plantings in your 156-day season

Sow every 6.9 weeks. Last sowing by Jul 15 to harvest before frost.

Black-eyed Susan Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.2" 3.2" 0" ✅ Rainfall sufficient
May 2.2" 3.9" 0" ✅ Rainfall sufficient
Jun 2.2" 4.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.7" 0" ✅ Rainfall sufficient
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Pottawattamie County). 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 ~1,068 GDD — county provides 2,379 GDD Excellent fit

Black-eyed Susan Planting Timeline — Pottawattamie County, IA

Black-eyed Susan Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors May 14 May 14 – May 28
Direct Sow April 30 Apr 30 – May 21
Bloom July 30 Jul 30 – Nov 5

· 18" apart · Rows 24" apart

Month-by-Month Timeline

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

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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

156 days in Pottawattamie County

Growing Tips for Black-eyed Susan in Pottawattamie County

Direct sow Black-eyed Susan outdoors after April 30 in Pottawattamie County when soil has warmed and frost danger has passed.

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 Pottawattamie County, IA?

Pottawattamie County is in Zone 5b with an average last frost of April 30. Plan your Black-eyed Susan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pottawattamie County, IA?

Pottawattamie County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 3.

When should I plant Black-eyed Susan in Pottawattamie County County, ?

In Pottawattamie County County, , plant Black-eyed Susan after the last frost (around April 30) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Pottawattamie County County, for Black-eyed Susan?

Pottawattamie County County sits in USDA Zone 5b. Black-eyed Susan grows reliably in zones 3a through 9b, so it's a good fit here.

Can Black-eyed Susan grow in Pottawattamie County County's climate?

Yes — Black-eyed Susan grows well in Pottawattamie County County's temperate climate. Pottawattamie County County averages a 156-day frost-free season, with last frost around April 30 and first frost around October 3.

🌱

Your Pottawattamie County Garden Planner — Free

A 22-page printable planner built for Pottawattamie County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Pottawattamie County, IA. 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.