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When to plant Ageratum in Isleton, CA

Plant Ageratum in Isleton, when soil hits 50°F — usually January 22. Continue planting through February 12 for the spring crop.

When to Plant Ageratum in Isleton, CA

Sacramento County, California Zone 9b June

June in the garden — Sacramento County, California

Your garden in Sacramento County, California is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost February 12
Avg. first frost December 1
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.7 hrs
  1. Basket week: ageratum

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of July
  • First harvests: ageratum

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Ageratum (Ageratum houstonianum), the floss flower, produces clusters of fluffy, powder-puff blooms in the rare sky-blue and lavender tones difficult to find among warm-season annuals. Compact mounding habit makes it ideal as a front-of-border edging plant. Blooms from early summer through fall with minimal deadheading; heat and humidity tolerant once established.

Isleton, California is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 1, giving you a growing season of approximately 292 days.

At an elevation of 263 feet, Sacramento County receives approximately 33.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Isleton, CA (Zone 9b) Year-round
292 days
Last Spring Frost February 12
292 growing days
First Fall Frost December 1

Isleton Soil Profile

Soil Type

Loam

Soil pH

6.4-7.1

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (86 days to spare)
Start indoors: Dec 15 Transplant: Jan 5 🌸 Bloom: Mar 2 – Aug 31
Recommended (50%) ✓ Fits season (75 days to spare)
Start indoors: Jan 1 Transplant: Jan 22 🌸 Bloom: Mar 19 – Sep 17
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: Feb 23 Transplant: Mar 16 🌸 Bloom: May 11 – Nov 9

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 Isleton

How your county's soil matches Ageratum's growing requirements.

Soil pH

Your soil pH (6.4–7.1) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Sacramento County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

5
successive plantings in your 292-day season

Sow every 6.9 weeks. Last sowing by Sep 17 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,640 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Ageratum

Ageratum needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Ageratum Needs Rainfall You Supplement Action
Jan 6.1" 0" ❄️ Dormant
Feb 4.3" 7.5" 0" ✅ Rainfall sufficient
Mar 4.3" 5.7" 0" ✅ Rainfall sufficient
Apr 4.3" 2.5" 1.8" 💧 Light watering
May 4.3" 0.8" 3.5" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.3" 4" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 4.3" 2.7" 1.6" 💧 Light watering
Dec 4.3" 5.9" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Sacramento County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Ageratum 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.

Ageratum needs ~1,181 GDD — county provides 5,127 GDD Excellent fit

Ageratum Planting Timeline — Isleton, CA

Ageratum Planting Calendar

Activity When Date Range
Start Indoors January 1 Jan 1 – Jan 15
Transplant Outdoors January 22 Jan 22 – Feb 5
Direct Sow January 22 Jan 22 – Feb 12
Bloom March 19 Mar 19 – Sep 17

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

292 days in Sacramento County

Growing Tips for Ageratum in Isleton

Direct sow Ageratum outdoors after February 12 in Sacramento County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 6–8 weeks before last frost — do not cover seed; it needs light to germinate. Can be direct-sown after last frost once soil warms to 60°F. Transplant or thin to proper spacing after frost danger passes. Deadheading isn't strictly required but tidying spent clusters improves appearance. Provide consistent moisture; drought causes premature setting. Avoid deep shade — blooms best in full sun to light afternoon shade.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Ageratum in Isleton, CA?

In Isleton, CA, plant Ageratum after the last frost (around February 12) and before the first frost (around December 1). Best results when soil holds above 50°F.

What growing zone is Isleton, CA for Ageratum?

Isleton sits in USDA Zone 9b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Isleton's climate?

Yes — Ageratum grows well in Isleton's temperate climate. Isleton averages a 293-day frost-free season, with last frost around February 12 and first frost around December 1.

🌱

Your Sacramento County Garden Planner — Free

A 22-page printable planner built for Sacramento 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 Sacramento County, CA. Local conditions may vary. Last updated: June 2026.