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When to plant Ageratum in Camas County, ID

Camas County sits in USDA Zone 5a. Plant Ageratum between May 10 (after last frost on May 3) and May 31.

When to Plant Ageratum in Camas County, ID

Camas County, Idaho Zone 5a June

June to-do list for Camas County, Idaho

Here's what deserves your attention in Camas County, Idaho this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost May 3
Avg. first frost October 3
Soil temp (4") 52°F
Watering High
Pest pressure High
Daylight 15.2 hrs
  1. Sow ageratum in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

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.

Camas County, Idaho is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 3, giving you a growing season of approximately 153 days.

At an elevation of 5,406 feet, Camas County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Camas County, ID (Zone 5a) Moderate season
153 days
Last Spring Frost May 3
153 growing days
First Fall Frost October 3

Camas County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.2

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Mar 11 Transplant: May 6 🌸 Bloom: Jul 1 – Sep 23
Recommended (50%) ✓ Fits season (6 days to spare)
Start indoors: Mar 15 Transplant: May 10 🌸 Bloom: Jul 5 – Sep 27
Safe Start (90%) ✗ May not fit
Start indoors: Apr 13 Transplant: Jun 8 🌸 Bloom: Aug 3 – Oct 26

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 Camas County

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

Soil pH

Your soil pH (6.4–8.2) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

2
successive plantings in your 153-day season

Sow every 6.9 weeks. Last sowing by Jul 20 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 674 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.3" 0" ❄️ Dormant
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.4" 1.9" 💧 Light watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Camas 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 ~1,029 GDD — county provides 2,333 GDD Excellent fit

Ageratum Planting Timeline — Camas County, ID

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 10 May 10 – May 31
Bloom July 5 Jul 5 – Sep 27

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
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: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

153 days in Camas County

Growing Tips for Ageratum in Camas County

Direct sow Ageratum outdoors after May 03 in Camas 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.

Camas County receives only 21" 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 →

Frequently Asked Questions

When should I plant Ageratum in Camas County, ID?

Camas County is in Zone 5a with an average last frost of May 3. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Camas County, ID?

Camas County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 3.

When should I plant Ageratum in Camas County, ID?

In Camas County, ID, plant Ageratum after the last frost (around May 3) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Camas County, ID for Ageratum?

Camas County sits in USDA Zone 5a. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Camas County's climate?

Yes — Ageratum grows well in Camas County's temperate climate. Camas County averages a 153-day frost-free season, with last frost around May 3 and first frost around October 3.

🌱

Your Camas County Garden Planner — Free

A 22-page printable planner built for Camas County (Zone 5a). 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 Camas County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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