When to plant Ageratum in Washington County, MO
In Zone 6b (Washington County), direct-sow Ageratum between April 10 and May 1 for spring, after the April 10 last-frost mark.
When to Plant Ageratum in Washington County, MO
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.
Washington County, Missouri is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 24, giving you a growing season of approximately 197 days.
At an elevation of 738 feet, Washington County receives approximately 36.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Ageratum during the growing season.
Washington County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Ageratum Planting Timeline — Washington 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
Moderate — regular watering
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 6b
📆 Growing Season
197 days in Washington County
Growing Tips for Washington County
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 Washington County, MO?
Washington 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 Washington County, MO?
Washington County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 24.
When should I plant Ageratum in Washington County, MO?
In Washington County, MO, plant Ageratum after the last frost (around April 10) and before the first frost (around October 24). Best results when soil holds above 50°F.
What growing zone is Washington County, MO for Ageratum?
Washington 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 Washington County's climate?
Yes — Ageratum grows well in Washington County's temperate climate. Washington County averages a 197-day frost-free season, with last frost around April 10 and first frost around October 24.
Your Washington County Garden Planner — Free
A 22-page printable planner built for Washington 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.