When to plant Ageratum in Platte County, MO
Plant Ageratum in Platte County, when soil hits 50°F — usually April 10. Continue planting through May 1 for the spring crop.
When to Plant Ageratum in Platte County, MO
June in Platte County, Missouri — your action list
Welcome to June in Zone 6b. These are the moves that will have the biggest impact on your growing season.
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Collect ageratum at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Before July arrives, get these ready
- 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.
Platte County, Missouri is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 26, giving you a growing season of approximately 199 days.
At an elevation of 1,021 feet, Platte County receives approximately 35.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Ageratum during the growing season.
Platte County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-7
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 Platte County
How your county's soil matches Ageratum's growing requirements.
Soil pH
Your soil pH (5.7–7.0) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Platte County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.1%). Annual compost additions will help Ageratum.
How to Plant Ageratum
Succession Planting Ageratum
Sow every 6.9 weeks. Last sowing by Aug 12 to harvest before frost.
Ageratum Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Platte 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 — Platte County, MO
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 20 | Feb 20 – Mar 6 |
| Transplant Outdoors | April 10 | Apr 10 – Apr 24 |
| Direct Sow | April 10 | Apr 10 – May 1 |
| Bloom | June 5 | Jun 5 – Sep 18 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Direct Sow |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
199 days in Platte County
Growing Tips for Ageratum in Platte County
Direct sow Ageratum outdoors after April 10 in Platte 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 →
Ageratum in Other Locations
Frequently Asked Questions
When should I plant Ageratum in Platte County, MO?
Platte County is in Zone 6b with an average last frost of April 10. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Platte County, MO?
Platte County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 26.
When should I plant Ageratum in Platte County, MO?
In Platte County, MO, plant Ageratum after the last frost (around April 10) and before the first frost (around October 26). Best results when soil holds above 50°F.
What growing zone is Platte County, MO for Ageratum?
Platte County sits in USDA Zone 6b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.
Can Ageratum grow in Platte County's climate?
Yes — Ageratum grows well in Platte County's temperate climate. Platte County averages a 199-day frost-free season, with last frost around April 10 and first frost around October 26.
Your Platte County Garden Planner — Free
A 22-page printable planner built for Platte County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.