When to plant Ageratum in Fresno County County,
The best window to plant Ageratum in Fresno County County, is February 9–March 2, when soil warms to 50°F. Last frost typically hits March 2; first frost November 23.
When to Plant Ageratum in Fresno County, CA
Your June gardening checklist
Here's what deserves your attention in Fresno County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.
-
Collect ageratum at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Coming up in July — start thinking about
- First harvests: ageratum
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.
Fresno County, California is in USDA Zone 9b. The average last spring frost is March 2 and the first fall frost is November 23, giving you a growing season of approximately 266 days.
At an elevation of 2,276 feet, Fresno County receives approximately 14.9 inches of rainfall annually with predominantly loam soil. Summer highs average 100°F, so Ageratum may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Ageratum successfully. Mulch heavily to conserve soil moisture.
Fresno County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.5
Drainage
Well Drained
Ageratum Planting Risk Windows
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 Fresno County
How your county's soil matches Ageratum's growing requirements.
Soil pH
Your soil pH (6.5–7.5) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Fresno County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.2%). Annual compost additions will help Ageratum.
How to Plant Ageratum
Succession Planting Ageratum
Sow every 6.9 weeks. Last sowing by Sep 09 to harvest before frost.
Ageratum Water Budget
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 | — | 2.8" | 0" | ❄️ Dormant |
| Feb | — | 3.3" | 0" | ❄️ Dormant |
| Mar | 4.3" | 2.3" | 2" | 💧 Light watering |
| Apr | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| May | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Jun | 4.3" | 0.1" | 4.2" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Oct | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Nov | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Dec | — | 2.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Fresno 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 Planting Timeline — Fresno County, CA
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 19 | Jan 19 – Feb 2 |
| Transplant Outdoors | February 9 | Feb 9 – Feb 23 |
| Direct Sow | February 9 | Feb 9 – Mar 2 |
| Bloom | April 6 | Apr 6 – Oct 5 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Direct Sow |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9b
📆 Growing Season
266 days in Fresno County
Growing Tips for Ageratum in Fresno County
Direct sow Ageratum outdoors after March 02 in Fresno County when soil has warmed and frost danger has passed.
With summer highs reaching 100°F in Fresno County, provide afternoon shade for Ageratum and water deeply in the morning.
Common pests for Ageratum in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Fresno County receives only 15" of rain annually. Ageratum needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 →
Ageratum in Other Locations
Frequently Asked Questions
When should I plant Ageratum in Fresno County, CA?
Fresno County is in Zone 9b with an average last frost of March 2. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Fresno County, CA?
Fresno County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 2 and first fall frost is November 23.
When should I plant Ageratum in Fresno County County, ?
In Fresno County County, , plant Ageratum after the last frost (around March 2) and before the first frost (around November 23). Best results when soil holds above 50°F.
What growing zone is Fresno County County, for Ageratum?
Fresno County County sits in USDA Zone 9b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.
Can Ageratum grow in Fresno County County's climate?
Yes — Ageratum grows well in Fresno County County's temperate climate. Fresno County County averages a 266-day frost-free season, with last frost around March 2 and first frost around November 23.
Your Fresno County Garden Planner — Free
A 22-page printable planner built for Fresno 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.