When to plant Hyacinths in Summit County, CO
In Summit County, plant Hyacinths in spring between mid-spring and late spring, once soil temps hold above 50°F. Summit County's last frost averages June 16, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between July 24 and August 7 — roughly 14–28 days before the first frost on September 4.
When to Plant Hyacinths in Summit County, CO
This month in Summit County, Colorado
June is a pivotal month for Summit County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.
July will be here before you know it — start on
- Fall sowing: hyacinths
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, Colorado is in USDA Zone 5a. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.
At an elevation of 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Hyacinths to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Hyacinths successfully. Mulch heavily to conserve soil moisture.
Summit County Soil Profile
Soil Type
Loam
Soil pH
6.8-8
Drainage
Well Drained
Hyacinths Planting Risk Windows
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 (6.8–8.0) 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.
Drainage
Drainage is adequate for Hyacinths.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Hyacinths.
How to Plant Hyacinths
Fall planting: Sow 6 weeks before your first frost date for a fall harvest.
Succession Planting Hyacinths
Sow every 1.6 weeks. Last sowing by Aug 07 to harvest before frost.
For a dedicated fall crop, sow by Jul 24.
Hyacinths Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.7" | 0" | ❄️ Dormant |
| May | — | 1.8" | 0" | ❄️ Dormant |
| Jun | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Jul | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Aug | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Sep | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Oct | — | 1.6" | 0" | ❄️ Dormant |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 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 Planting Timeline — Summit County, CO
Hyacinths Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Bloom | July 3 | Jul 3 – Jul 31 |
| Fall Sowing | July 24 | Jul 24 – Aug 7 |
Plant 6" deep · 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | Fall Sowing Bloom |
| August | Fall Sowing |
| 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 5a
📆 Growing Season
80 days in Summit County
Growing Tips for Hyacinths in Summit County
Direct sow Hyacinths outdoors after June 16 in Summit County when soil has warmed and frost danger has passed.
Your generous 80.0-day season in Summit County allows multiple plantings of Hyacinths. Sow every 7.0 days for continuous harvest.
Summit County receives only 18" 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 →
Hyacinths in Other Locations
Frequently Asked Questions
When should I plant Hyacinths in Summit County, CO?
Summit County is in Zone 5a with an average last frost of June 16. Plan your Hyacinths planting based on this frost date — see the calendar above for exact timing.
What planting zone is Summit County, CO?
Summit County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 4.
When should I plant Hyacinths in Summit County, CO?
In Summit County, CO, plant Hyacinths after the last frost (around June 16) and before the first frost (around September 4). Best results when soil holds above 50°F.
What growing zone is Summit County, CO for Hyacinths?
Summit County sits in USDA Zone 5a. Hyacinths grows reliably in zones 3a through 9b, so it's a good fit here.
Can Hyacinths grow in Summit County's climate?
Yes — Hyacinths grows well in Summit County's temperate climate. Summit County averages a 80-day frost-free season, with last frost around June 16 and first frost around September 4.
Your Summit County Garden Planner — Free
A 22-page printable planner built for Summit County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.