When to Plant Petunia in Wisconsin
Petunias (Petunia x hybrida) are warm-season tender annuals prized for their prolific, trumpet-shaped blooms in nearly every color. They perform from hanging baskets to garden borders and bloom continuously from late spring until frost, provided spent flowers are removed regularly.
Wisconsin spans USDA hardiness zones 4a, 4b, 5a, 5b, 6a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.
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Click your county for exact Petunia planting dates based on your local frost dates.
Hover over a county to see details. Click to view planting guide.
Petunia Planting Calendar for Wisconsin
▸ Zone 4a ~145 day growing season · Full guide →
Last frost: May 6 · First frost: September 28 · 145 day season
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 4 | Mar 4 – Mar 18 |
| Transplant Outdoors | May 20 | May 20 – Jun 3 |
| Bloom | August 5 | Aug 5 – Oct 7 |
▸ Zone 4b ~155 day growing season · Full guide →
Last frost: May 1 · First frost: October 3 · 155 day season
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | May 8 | May 8 – May 22 |
| Bloom | July 17 | Jul 17 – Oct 2 |
▸ Zone 5a ~166 day growing season · Full guide →
Last frost: April 25 · First frost: October 8 · 166 day season
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 28 | Feb 28 – Mar 14 |
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Bloom | July 11 | Jul 11 – Oct 3 |
▸ Zone 5b ~178 day growing season · Full guide →
Last frost: April 18 · First frost: October 13 · 178 day season
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 21 | Feb 21 – Mar 7 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Bloom | July 4 | Jul 4 – Oct 3 |
▸ Zone 6a ~193 day growing season · Full guide →
Last frost: April 10 · First frost: October 20 · 193 day season
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 13 | Feb 13 – Feb 27 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Bloom | June 26 | Jun 26 – Oct 2 |
Growing Tips for Wisconsin
Start seeds indoors 8–10 weeks before last frost; seeds need light to germinate — press onto moist mix surface, do not cover. Transplant after last frost once nights stay above 50°F. Pinch back leggy plants mid-summer to encourage bushy re-bloom. Wave/spreading types tolerate light shade but bloom less. Feed every 2 weeks with balanced fertilizer once established.
Petunia in Other States
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wyoming
Frequently Asked Questions
When should I plant Petunia in Wisconsin?
Planting dates for Petunia in Wisconsin depend on your USDA zone. Wisconsin spans zones 4a, 4b, 5a, 5b, 6a. Check the planting calendar above for your specific zone's frost dates and planting windows.
What zone is Wisconsin for planting?
Wisconsin contains USDA hardiness zones 4a, 4b, 5a, 5b, 6a. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.