When to Plant Yarrow in USDA Zone 4b
June to-do list for Zone 4b
June is a pivotal month for Zone 4b gardens. Focus on these tasks first and you'll set up the rest of the season for success.
July will be here before you know it — start on
- Starting indoors: yarrow
Achillea millefolium (Yarrow) is a tough, drought-tolerant native perennial with aromatic finely-divided foliage and broad flat-topped flower clusters that serve as a landing platform for hundreds of beneficial insect species. Available in white (the species type) and a wide range of cultivars spanning yellow, gold, pink, salmon, and deep red. Spreads by rhizome to form ground-covering colonies; blooms from late spring through midsummer with reblooming into fall if deadheaded. Exceptional in hot, dry sites where other perennials fail.
In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.
Yarrow Planting Timeline — Zone 4b
Where Is USDA Zone 4b?
The map below highlights the states that contain Zone 4b. Click any state to see the Yarrow planting schedule for that location.
Yarrow Planting Calendar — Zone 4b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 20 | Feb 20 – Mar 6 |
| Transplant Outdoors | May 15 | May 15 – May 29 |
| Direct Sow | May 1 | May 1 – May 22 |
| Bloom | July 31 | Jul 31 – Oct 23 |
· 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Free Zone 4b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
Days to Maturity
60–90 days
Soil pH
5.5 – 7
Zone Temperature Range
-25°F to -20°F average annual minimum
Growing Season
155 days (Zone 4b average)
Planting Specifications
| Plant Spacing | 18 inches apart |
| Row Spacing | 24 inches between rows |
Succession Planting Yarrow in Zone 4b
Sow every 6.9 weeks for continuous harvest throughout the season.
Growing Tips for Yarrow in Zone 4b
Zone 4b has a short growing season (~155 days). Start Yarrow indoors early and use season-extension techniques like row covers and cold frames.
Start seeds indoors 8–10 weeks before last frost; seeds need light for germination — press onto soil surface, do not cover. Direct sow after last frost or divide established clumps in spring or fall. Thrives in poor, well-drained soil — rich soil and high fertility cause floppy stems and reduce flower count. Avoid overwatering; excellent drought tolerance once established. Deadhead spent clusters to encourage rebloom. Divide every 2–3 years to prevent center die-out and control spread. Year 2+ plants bloom most heavily; first-year plants may produce limited flowers. Dried flowers retain color well for arrangements.
Companion Planting
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The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
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Saving Yarrow Seeds
Recommended for Your Garden
Full-spectrum LED lights for starting seeds indoors when daylight is limited.
Warm soil for faster germination of heat-loving crops like tomatoes and peppers.
Protect plants from frost, wind, and pests while letting light and water through.
Related Plants
Yarrow in Other Zones
Yarrow by State
- 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
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Yarrow in Zone 4b?
In Zone 4b, plan your Yarrow planting around the average last frost date of May 1. Start seeds indoors around February 20. Direct sow outdoors around May 1. Transplant seedlings around May 15.
Can Yarrow grow in Zone 4b?
Yes, Yarrow can grow well in Zone 4b, hardy in USDA zones 3a through 9b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Yarrow (60-90 days to maturity).
When can I harvest Yarrow in Zone 4b?
In Zone 4b, expect to harvest Yarrow from July 31 – October 23. Yarrow takes 60-90 days from planting to harvest.
What is the last frost date for Zone 4b?
The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Yarrow?
Good companion plants for Yarrow include Echinacea, Black Eyed Susan, Lavender, Salvia. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 4b Garden Planner — Free
A 22-page printable planner tailored to Zone 4b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.