When to plant Ageratum in Cook County, MN
Cook County's short 132-day growing season means one Ageratum planting between June 3 and June 24. No fall crop in Zone 3b.
When to Plant Ageratum in Cook County, MN
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.
Cook County, Minnesota is in USDA Zone 3b. The average last spring frost is May 20 and the first fall frost is September 29, giving you a growing season of approximately 132 days.
At an elevation of 1,068 feet, Cook County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Ageratum to ensure they mature before fall.
Cook County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Ageratum Planting Timeline — Cook County, MN
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 25 | Mar 25 – Apr 8 |
| Transplant Outdoors | June 3 | Jun 3 – Jun 17 |
| Direct Sow | June 3 | Jun 3 – Jun 24 |
| Bloom | July 29 | Jul 29 – Sep 30 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | — |
| June | Transplant Outdoors Direct Sow |
| 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 3b
📆 Growing Season
132 days in Cook County
Growing Tips for Cook 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 Cook County, MN?
Cook County is in Zone 3b with an average last frost of May 20. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cook County, MN?
Cook County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 20 and first fall frost is September 29.
When should I plant Ageratum in Cook County, MN?
In Cook County, MN, plant Ageratum after the last frost (around May 20) and before the first frost (around September 29). Best results when soil holds above 50°F.
What growing zone is Cook County, MN for Ageratum?
Cook County sits in USDA Zone 3b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.
Can Ageratum grow in Cook County's climate?
Yes — Ageratum grows well in Cook County's temperate climate. Cook County averages a 132-day frost-free season, with last frost around May 20 and first frost around September 29.
Your Cook County Garden Planner — Free
A 22-page printable planner built for Cook County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.