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When to Plant Lilies in Summit County, UT

Summit County, Utah Zone 5b June

This month in Summit County, Utah

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

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

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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Lilies (Lilium spp.) are among the most impressive summer-blooming bulbs, delivering bold, upward- or outward-facing trumpet blooms on tall stems from June through August. Asiatic hybrids are the most cold-hardy, earliest to bloom, and easiest to grow; Oriental hybrids bloom later with intensely fragrant, larger flowers. Orienpet (OT) hybrids combine the hardiness of Asiatics with the fragrance and size of Orientals. True lilies (not to be confused with daylilies, which are Hemerocallis) form scaly bulbs that persist and multiply underground, returning reliably each year with increasingly large clumps.

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 Lilies during the growing season.

Perennial Blooms in Summer Pollinator-friendly 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

Lilies Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 13 🌸 Bloom: Aug 22 – Nov 21
Recommended (50%) ✗ May not fit
Transplant: Jun 24 🌸 Bloom: Sep 2 – Dec 2
Safe Start (90%) ✗ May not fit
Transplant: Jul 5 🌸 Bloom: Sep 13 – Dec 13

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 Lilies's growing requirements.

Soil pH

Your soil pH (6.4–8.3) is more alkaline than Lilies prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Lilies

5"
Planting Depth
12"
Between Plants
18"
Between Rows

Lilies Water Budget

Plant needs
1.0″/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 Lilies

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

Month Lilies 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 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular 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.

Lilies 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.

Lilies needs ~1,378 GDD — county provides 1,363 GDD Tight fit

Lilies Planting Timeline — Summit County, UT

Lilies Planting Calendar

Activity When Date Range
Transplant Outdoors June 24 Jun 24 – Jul 8
Bloom September 2 Sep 2 – Dec 2

Plant 5" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

94 days in Summit County

Growing Tips for Lilies in Summit County

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

Your 94.0-day growing season in Summit County is tight for Lilies (70.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Plant bulbs in fall (preferred, September–October) or spring, setting them 3 times their diameter deep (typically 4–6 inches) with the pointed end up. Lilies need excellent drainage — they will rot in wet or heavy clay soils. Site with full sun on stems and blooms but cool, shaded soil at the base (ground cover or shallow-rooted annuals at their feet is ideal). Remove spent blooms but leave stems and foliage until they yellow naturally, as the bulb needs the foliage to photosynthesize and rebuild energy stores. Red lily beetle is a serious pest in the Northeast and Pacific Northwest; inspect plants regularly and hand-pick adults and larvae. Never plant Oriental or Asiatic lilies near cats — all Lilium species are highly toxic to cats. Year 2+ bulbs produce the most stems and largest blooms.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lilies in Summit County, UT?

Summit County is in Zone 5b with an average last frost of June 10. Plan your Lilies 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.