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When to Plant Hydrangeas in Matlock, WA

Mason County, Washington Zone 8b June

Mason County, Washington gardeners: here's your June plan

June is a pivotal month for Mason County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 18
Avg. first frost October 29
Soil temp (4") 80°F
Watering High
Pest pressure High
Daylight 15.7 hrs
  1. Get hydrangeas seeds going inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Collect hydrangeas at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Coming up in July — start thinking about
  • First harvests: hydrangeas

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Hydrangeas (Hydrangea spp.) are among the most spectacular summer-blooming shrubs, with large mophead, lacecap, or panicle flower clusters lasting weeks in the garden and drying beautifully for arrangements. Native to Asia and North America alike, the genus spans several garden species with different hardiness and blooming habits. Panicle hydrangeas (H. paniculata, e.g., Limelight) are the most cold-hardy (Zone 3) and most reliable bloomers; smooth hydrangeas (H. arborescens, e.g., Annabelle) are equally tough. Bigleaf hydrangeas (H. macrophylla) are prized for blue/pink color-shifting blooms but require reliable snow cover or winter protection in Zones 5–6. Flower color in macrophylla types is determined by soil pH (acidic = blue, alkaline = pink).

Matlock, Washington is in USDA Zone 8b. The average last spring frost is April 18 and the first fall frost is October 29, giving you a growing season of approximately 194 days.

At an elevation of 230 feet, Mason County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Hydrangeas during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting
Matlock, WA (Zone 8b) Moderate season
194 days
Last Spring Frost April 18
194 growing days
First Fall Frost October 29

Matlock Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Hydrangeas Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Feb 1 Transplant: Mar 29 🌸 Bloom: Jun 7 – Oct 11
Recommended (50%) ✓ Fits season (5 days to spare)
Start indoors: Feb 14 Transplant: Apr 11 🌸 Bloom: Jun 20 – Oct 24
Safe Start (90%) ✓ Fits season (18 days to spare)
Start indoors: Mar 7 Transplant: May 2 🌸 Bloom: Jul 11 – Nov 14

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 Matlock

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

Soil pH

Your soil pH (5.4–6.7) overlaps with Hydrangeas's range (5.5–6.5), though not a perfect match.

Soil Texture

The silt loam soil in Mason County is excellent for Hydrangeas — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.3%) — Hydrangeas will thrive.

How to Plant Hydrangeas

1"
Planting Depth
48"
Between Plants
60"
Between Rows

Hydrangeas Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 362 gal / 100 sq ft

Monthly Watering Guide for Hydrangeas

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

Month Hydrangeas Needs Rainfall You Supplement Action
Jan 5" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 1.8" 2.5" 🚿 Regular watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 6.5" 0" ❄️ Dormant
Dec 5.3" 0" ❄️ Dormant

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

Hydrangeas 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.

Hydrangeas needs ~1,650 GDD — county provides 2,667 GDD Excellent fit

Hydrangeas Planting Timeline — Matlock, WA

Hydrangeas Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors April 11 Apr 11 – Apr 25
Bloom June 20 Jun 20 – Oct 24

Plant 1" deep · 48" apart · Rows 60" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

194 days in Mason County

Growing Tips for Hydrangeas in Matlock

Direct sow Hydrangeas outdoors after April 18 in Mason County when soil has warmed and frost danger has passed.

General growing tips

Plant container-grown specimens in spring or fall, spacing at least 3–5 feet apart to allow for mature shrub spread. Most hydrangeas prefer morning sun with afternoon shade, especially in Zones 7+. Keep consistently moist — the name derives from the Greek for water vessel. Prune panicle and smooth types in late winter/early spring (they bloom on new wood). Prune bigleaf types only lightly after bloom; cutting stems in fall removes next year's buds. In Zone 5–6, protect bigleaf varieties with burlap or wire cages filled with leaves over winter. Fall planting (Zones 5+) gives excellent root establishment before summer heat. Year 2+ plants reach full size and bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

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Your Mason County Garden Planner — Free

A 22-page printable planner built for Mason County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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