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When to Plant Yarrow in Mono County, CA

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.

Mono County, California is in USDA Zone 5b. The average last spring frost is June 18 and the first fall frost is August 20, giving you a growing season of approximately 63 days.

At an elevation of 2,381 feet, Mono County receives approximately 13.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Yarrow to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Yarrow successfully. Mulch heavily to conserve soil moisture.

Mono County, CA (Zone 5b) Very short season
63 days
Last Spring Frost June 18
63 growing days
First Fall Frost August 20

Mono County Soil Profile

Soil Type

Loam

Soil pH

6-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 29 🍅 Harvest: Aug 28 – Nov 13
Recommended (50%) ✗ May not fit
Transplant: Jun 25 🍅 Harvest: Sep 24 – Dec 10
Safe Start (90%) ✗ May not fit
Transplant: Jul 7 🍅 Harvest: Oct 6 – Dec 22

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 Mono County

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

Soil pH

Your soil pH (6.0โ€“7.5) overlaps with Yarrow's range (5.5โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Mono County is excellent for Yarrow โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). 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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 2.7" 0" โ„๏ธ Dormant
Feb โ€” 3.1" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 1" 0" โ„๏ธ Dormant
May โ€” 0.3" 0" โ„๏ธ Dormant
Jun 2.2" 0.1" 2.1" ๐Ÿšฟ Regular watering
Jul 2.2" 0" 2.2" ๐Ÿšฟ Regular watering
Aug 2.2" 0" 2.2" ๐Ÿšฟ Regular watering
Sep โ€” 0.2" 0" โ„๏ธ Dormant
Oct โ€” 0.6" 0" โ„๏ธ Dormant
Nov โ€” 1.1" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Aug in Mono County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,365 GDD — county provides 819 GDD May not mature

Yarrow Planting Timeline โ€” Mono County, CA

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors June 25 Jun 25 โ€“ Jul 9
Harvest September 24 Sep 24 โ€“ Dec 10

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Transplant Outdoors
July Transplant Outdoors
August โ€”
September Harvest
October Harvest
November Harvest
December Harvest

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

63 days in Mono County

Growing Tips for Yarrow in Mono County

Direct sow Yarrow outdoors after June 18 in Mono County when soil has warmed and frost danger has passed.

Your 63.0-day growing season in Mono County is tight for Yarrow (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Mono County receives only 13" of rain annually. Yarrow needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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 Mono County, CA?

Mono County is in Zone 5b with an average last frost of June 18. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mono County, CA?

Mono County, California is in USDA Hardiness Zone 5b. The average last spring frost is June 18 and first fall frost is August 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Mono County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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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 Mono County, CA. Local conditions may vary. Last updated: April 2026.