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When to plant Black-eyed Susan in Santa Cruz County County,

Santa Cruz County County's climate puts the Black-eyed Susan spring window between January 21 and February 11. aim for a steady week of warm soil before planting.

When to Plant Black-eyed Susan in Santa Cruz County, CA

Santa Cruz County, California Zone 9b June

June to-do list for Santa Cruz County, California

Here's what deserves your attention in Santa Cruz County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 11
Avg. first frost December 4
Soil temp (4") 85°F
Watering Critical
Pest pressure High
Daylight 14.5 hrs
  1. Pick black-eyed susan

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

Before July arrives, get these ready
  • 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.

Santa Cruz County, California is in USDA Zone 9b. The average last spring frost is February 11 and the first fall frost is December 4, giving you a growing season of approximately 296 days.

At an elevation of 353 feet, Santa Cruz County receives approximately 18.3 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Black-eyed Susan during the growing season. With low rainfall, drip irrigation is essential for growing Black-eyed Susan successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Santa Cruz County, CA (Zone 9b) Year-round
296 days
Last Spring Frost February 11
296 growing days
First Fall Frost December 4
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Santa Cruz County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Black-eyed Susan Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Start indoors: Dec 3 Transplant: Jan 14 🌸 Bloom: Mar 25 – Aug 12
Recommended (50%) ✓ Fits season (100 days to spare)
Start indoors: Dec 17 Transplant: Jan 28 🌸 Bloom: Apr 8 – Aug 26
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: Jan 20 Transplant: Mar 3 🌸 Bloom: May 12 – Sep 29

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 Santa Cruz County

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

Soil pH

Your soil pH (6.4–7.7) is more alkaline than Black-eyed Susan prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help 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 296-day season

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

Black-eyed Susan Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 765 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 3.6" 0" ❄️ Dormant
Feb 2.2" 4.2" 0" ✅ Rainfall sufficient
Mar 2.2" 2.8" 0" ✅ Rainfall sufficient
Apr 2.2" 1.5" 0.7" 💧 Light watering
May 2.2" 0.5" 1.7" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.6" 0.6" 💧 Light watering
Dec 2.2" 3" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Santa Cruz 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 ~1,435 GDD — county provides 6,088 GDD Excellent fit

Black-eyed Susan Planting Timeline — Santa Cruz County, CA

Black-eyed Susan Planting Calendar

Activity When Date Range
Start Indoors December 17 Dec 17 – Dec 31
Transplant Outdoors January 28 Jan 28 – Feb 11
Direct Sow January 21 Jan 21 – Feb 11
Bloom April 8 Apr 8 – Aug 26

· 18" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

296 days in Santa Cruz County

Growing Tips for Black-eyed Susan in Santa Cruz County

Direct sow Black-eyed Susan outdoors after February 11 in Santa Cruz 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.

Santa Cruz County receives only 18" of rain annually. Black-eyed Susan needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Santa Cruz County, CA?

Santa Cruz County is in Zone 9b with an average last frost of February 11. Plan your Black-eyed Susan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Santa Cruz County, CA?

Santa Cruz County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 11 and first fall frost is December 4.

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

In Santa Cruz County County, , plant Black-eyed Susan after the last frost (around February 11) and before the first frost (around December 4). Best results when soil holds above 50°F.

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

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

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

Yes — Black-eyed Susan grows well in Santa Cruz County County's temperate climate. Santa Cruz County County averages a 297-day frost-free season, with last frost around February 11 and first frost around December 4.

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Your Santa Cruz County Garden Planner — Free

A 22-page printable planner built for Santa Cruz County (Zone 9b). 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 Santa Cruz County, CA. 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.