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When to Plant Yarrow in Assumption Parish, LA

Assumption Parish, Louisiana Zone 9b May

Your May game plan for Assumption Parish, Louisiana

May is a pivotal month for Assumption Parish, Louisiana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 13
Avg. first frost December 5
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest yarrow as they ripen

    If you can't use it all right away, check the food-preservation section of your planner.

Coming up in June — start thinking about
  • First harvests: yarrow

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Yarrow is a drought-tolerant perennial herb with feathery foliage and flat-topped flower clusters in white, yellow, pink, or red. It attracts beneficial insects and is used in herbal medicine.

Assumption Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 13 and the first fall frost is December 5, giving you a growing season of approximately 295 days.

At an elevation of 126 feet, Assumption Parish receives approximately 55.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 104°F, so Yarrow may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Yarrow will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yarrow root diseases.

Assumption Parish, LA (Zone 9b) Year-round
295 days
Last Spring Frost February 13
295 growing days
First Fall Frost December 5
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Assumption Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (121 days to spare)
Transplant: Feb 11 🍅 Harvest: May 13 – Jul 29
Recommended (50%) ✓ Fits season (120 days to spare)
Transplant: Feb 20 🍅 Harvest: May 22 – Aug 7
Safe Start (90%) ✓ Fits season (111 days to spare)
Transplant: Mar 16 🍅 Harvest: Jun 15 – Aug 31

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 Assumption Parish

How your county's soil matches Yarrow's growing requirements.

Soil pH

Your soil pH (5.0–6.3) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.

Soil Texture

Sandy soil in Assumption Parish warms quickly in spring but drains fast. Yarrow will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Yarrow prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Yarrow.

How to Plant Yarrow

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Yarrow

Yarrow needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Yarrow Needs Rainfall You Supplement Action
Jan 4.4" 0" ❄️ Dormant
Feb 2.2" 4.6" 0" ✅ Rainfall sufficient
Mar 2.2" 5.5" 0" ✅ Rainfall sufficient
Apr 2.2" 4.3" 0" ✅ Rainfall sufficient
May 2.2" 4.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.8" 0" ✅ Rainfall sufficient
Jul 2.2" 6.2" 0" ✅ Rainfall sufficient
Aug 2.2" 5" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 2.2" 4.2" 0" ✅ Rainfall sufficient
Dec 2.2" 4.6" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Assumption Parish). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Yarrow 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.

Yarrow needs ~2,940 GDD — county provides 8,288 GDD Excellent fit

Yarrow Planting Timeline — Assumption Parish, LA

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors February 20 Feb 20 – Mar 6
Harvest May 22 May 22 – Aug 7

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Transplant Outdoors
March Transplant Outdoors
April
May Harvest
June Harvest
July Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

295 days in Assumption Parish

Growing Tips for Yarrow in Assumption Parish

Direct sow Yarrow outdoors after February 13 in Assumption Parish when soil has warmed and frost danger has passed.

Sandy soil in Assumption Parish dries quickly — mulch Yarrow with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 104°F in Assumption Parish, provide afternoon shade for Yarrow and water deeply in the morning.

Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow or start from divisions. Yarrow thrives in poor soil and is very drought-tolerant. Deadhead to encourage reblooming. Divide clumps every 3 years.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yarrow in Assumption Parish, LA?

Assumption Parish is in Zone 9b with an average last frost of February 13. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Assumption Parish, LA?

Assumption Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 13 and first fall frost is December 5.

🌱

Your Assumption Parish Garden Planner — Free

A 24-page printable planner built for Assumption Parish (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Assumption Parish, LA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.