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When to plant Phlox in Mono County County,

In Mono County County, Phlox is a spring-only crop. Plant June 25–July 16 once soil hits 50°F.

When to Plant Phlox in Mono County, CA

Mono County, California Zone 6b June

Top priorities for Mono County, California gardeners in June

Each item below is timed to Mono County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost June 18
Avg. first frost August 20
Soil temp (4") 65°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
  1. Move phlox into the garden

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Scatter phlox into prepared beds

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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Garden Phlox (Phlox paniculata) is a beloved native perennial of eastern North America, producing large, domed clusters of fragrant flowers atop upright stems from mid-summer into fall. Its sweet honey-like fragrance carries on summer evenings and draws hummingbirds, butterflies, and sphinx moths. Modern cultivars offer colors spanning white, pink, salmon, red, purple, and bicolors. A classic cottage garden stalwart, phlox combines well with black-eyed Susans, echinacea, and ornamental grasses in naturalistic plantings. Select mildew-resistant cultivars for best long-term performance.

Mono County, California is in USDA Zone 6b. 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 84°F, so choose short-season varieties of Phlox to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Phlox successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Mono County, CA (Zone 6b) 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

Phlox Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 20 Transplant: May 29 🌸 Bloom: Aug 7 – Oct 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 16 Transplant: Jun 25 🌸 Bloom: Sep 3 – Nov 26
Safe Start (90%) ✗ May not fit
Start indoors: Apr 28 Transplant: Jul 7 🌸 Bloom: Sep 15 – Dec 8

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 Phlox's growing requirements.

Soil pH

Your soil pH (6.0–7.5) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Mono County is excellent for Phlox — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Phlox.

How to Plant Phlox

0.3"
Planting Depth
18"
Between Plants
24"
Between Rows

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 76 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Phlox

Phlox needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Phlox Needs Rainfall You Supplement Action
Jan 2.7" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1" 0" ❄️ Dormant
May 0.3" 0" ❄️ Dormant
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 0.2" 0" ❄️ Dormant
Oct 0.6" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Aug in Mono County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Phlox 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.

Phlox needs ~1,235 GDD — county provides 819 GDD May not mature

Phlox Planting Timeline — Mono County, CA

Phlox Planting Calendar

Activity When Date Range
Start Indoors April 16 Apr 16 – Apr 30
Transplant Outdoors June 25 Jun 25 – Jul 9
Direct Sow June 25 Jun 25 – Jul 16
Bloom September 3 Sep 3 – Nov 26

Plant 0.3" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May
June Transplant Outdoors Direct Sow
July Transplant Outdoors Direct Sow
August
September Bloom
October Bloom
November Bloom
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

63 days in Mono County

Growing Tips for Phlox in Mono County

Direct sow Phlox 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 Phlox (80.0-110.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Start seeds indoors 8–10 weeks before last frost, or transplant container divisions in spring. Named cultivar seeds may not come true; divisions from named plants are the preferred propagation method. Space generously (18–24 inches) and avoid overhead watering to reduce powdery mildew risk. Good air circulation is critical — thin clumps to the strongest 5–7 stems per plant in spring. Deadhead after the primary bloom flush to encourage secondary flowering. Division every 2–3 years in spring keeps plants vigorous. Fall planting of divisions (Zones 5+) is equally effective. Year 2+ plants develop into full clumps with the most prolific bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Phlox in Mono County, CA?

Mono County is in Zone 6b with an average last frost of June 18. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mono County, CA?

Mono County, California is in USDA Hardiness Zone 6b. The average last spring frost is June 18 and first fall frost is August 20.

When should I plant Phlox in Mono County County, ?

In Mono County County, , plant Phlox after the last frost (around June 18) and before the first frost (around August 20). Best results when soil holds above 50°F.

What growing zone is Mono County County, for Phlox?

Mono County County sits in USDA Zone 6b. Phlox grows reliably in zones 3a through 9a, so it's a good fit here.

Can Phlox grow in Mono County County's climate?

Yes — Phlox grows well in Mono County County's temperate climate. Mono County County averages a 63-day frost-free season, with last frost around June 18 and first frost around August 20.

🌱

Your Mono County Garden Planner — Free

A 22-page printable planner built for Mono County (Zone 6b). 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 Mono County, CA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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