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When to Plant Hyacinths in Summit County, UT

Summit County, Utah Zone 5b June

Summit County, Utah gardeners: here's your June plan

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Summit County, Utah.

Avg. last frost June 10
Avg. first frost September 12
Soil temp (4") 45°F
Watering High
Pest pressure High
Daylight 14.9 hrs

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Hyacinths (Hyacinthus orientalis) fill the spring garden with an almost overwhelming fragrance — a single cluster of blooms can perfume an entire yard. Dense, upright spikes of waxy florets in shades of purple, pink, blue, white, and red emerge in mid-spring, bridging the gap between the first crocus and the tulip peak. Though bulbs bloom most spectacularly in their first year, established plantings continue to produce graceful, less-dense flower spikes for several years. Deer and rabbits avoid them due to toxic alkaloids.

Summit County, Utah is in USDA Zone 5b. The average last spring frost is June 10 and the first fall frost is September 12, giving you a growing season of approximately 94 days.

At an elevation of 8,145 feet, Summit County receives approximately 24.8 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Hyacinths during the growing season.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Summit County, UT (Zone 5b) Very short season
94 days
Last Spring Frost June 10
94 growing days
First Fall Frost September 12

Summit County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.3

Drainage

Well Drained

Hyacinths Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 30 🌸 Bloom from: May 9
Recommended (50%) ✓ Fits season
Transplant: Jun 10 🌸 Bloom from: May 20
Safe Start (90%) ✓ Fits season
Transplant: Jun 21 🌸 Bloom from: May 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 Summit County

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

Soil pH

Your soil pH (6.4–8.3) overlaps with Hyacinths's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Hyacinths.

How to Plant Hyacinths

6"
Planting Depth
6"
Between Plants
8"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Hyacinths

8
successive plantings in your 94-day season

Sow every 1.6 weeks. Last sowing by Aug 15 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

Hyacinths Water Budget

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

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Hyacinths

Hyacinths 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 Hyacinths Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.9" 0" ❄️ Dormant
Jun 2.2" 1.8" 0.4" 💧 Light watering
Jul 2.2" 1.9" 0.3" 💧 Light watering
Aug 2.2" 2.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.1" 0" ❄️ Dormant
Nov 2" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Hyacinths 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.

Hyacinths needs ~304 GDD — county provides 1,363 GDD Excellent fit

Hyacinths Planting Timeline — Summit County, UT

Hyacinths Planting Calendar

Activity When Date Range
Bloom July 11 Jul 11 – Aug 8
Fall Sowing August 1 Aug 1 – Aug 15

Plant 6" deep · 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July Bloom
August Fall Sowing Bloom
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

14–28 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

94 days in Summit County

Growing Tips for Hyacinths in Summit County

Direct sow Hyacinths outdoors after June 10 in Summit County when soil has warmed and frost danger has passed.

Your generous 94.0-day season in Summit County allows multiple plantings of Hyacinths. Sow every 7.0 days for continuous harvest.

Summit County receives only 25" of rain annually. Hyacinths needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant bulbs 6 inches deep and 6 inches apart in fall, when soil drops below 60°F. Wear gloves when handling — bulb sap causes contact dermatitis in some people. After bloom, deadhead the spent spike but leave the strap-like foliage until it yellows naturally. For naturalizing, plant at 6–8 inch spacings and allow clumps to mature undisturbed. In zones 7b–9b, treat bulbs as annuals or use pre-chilled stock; performance after year 1 declines in warm-winter zones. For forcing indoors, chill bulbs 10–12 weeks then bring into warmth.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyacinths in Summit County, UT?

Summit County is in Zone 5b with an average last frost of June 10. Plan your Hyacinths planting based on this frost date — see the calendar above for exact timing.

What planting zone is Summit County, UT?

Summit County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is June 10 and first fall frost is September 12.

🌱

Your Summit County Garden Planner — Free

A 22-page printable planner built for Summit County (Zone 5b). 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 Summit County, UT. 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.