When to plant Bleeding Hearts in Boulder County, CO
Boulder County's 135-day season only supports one Bleeding Hearts planting per year. Sow between May 21 and June 4 for the best chance at full maturity before September 26.
When to Plant Bleeding Hearts in Boulder County, CO
Your July game plan for Boulder County, Colorado
A quick July briefing for Boulder County, Colorado gardeners — what's urgent, what's next, and what can wait.
Bleeding Hearts (Lamprocapnos spectabilis) are elegant woodland perennials producing arching stems hung with distinctive heart-shaped pink or white flowers with protruding inner petals — the "drops" beneath each heart. A beloved heirloom perennial from Asia, bleeding hearts emerge vigorously in spring, bloom prolifically for 4–6 weeks, and then go dormant in summer heat — a natural die-back that is entirely normal. The dormancy gap should be planned for by interplanting with summer-emerging hostas, ferns, or impatiens. Fringed bleeding heart (Dicentra eximia), a US native, has a longer bloom season and does not go fully dormant. All parts are toxic if ingested.
Boulder County, Colorado is in USDA Zone 6a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.
At an elevation of 7,657 feet, Boulder County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Bleeding Hearts during the growing season.
Boulder County Soil Profile
Soil Type
Loam
Soil pH
6.7-8
Drainage
Well Drained
Bleeding Hearts 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 Boulder County
How your county's soil matches Bleeding Hearts's growing requirements.
Soil pH
Your soil pH (6.7–8.0) is more alkaline than Bleeding Hearts prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Boulder County is excellent for Bleeding Hearts — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Bleeding Hearts.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Bleeding Hearts.
How to Plant Bleeding Hearts
Succession Planting Bleeding Hearts
Sow every 6.9 weeks. Last sowing by Jun 28 to harvest before frost.
Bleeding Hearts Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Bleeding Hearts
Bleeding Hearts needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Bleeding Hearts Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | 4.3" | 3" | 1.3" | 💧 Light watering |
| Jun | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jul | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Aug | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Sep | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Boulder County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Bleeding Hearts 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.
Bleeding Hearts Planting Timeline — Boulder County, CO
Bleeding Hearts Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 12 | Mar 12 – Mar 26 |
| Transplant Outdoors | May 21 | May 21 – Jun 4 |
| Bloom | July 16 | Jul 16 – Aug 20 |
Plant 1.5" deep · 24" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 6a
📆 Growing Season
135 days in Boulder County
Growing Tips for Bleeding Hearts in Boulder County
Direct sow Bleeding Hearts outdoors after May 14 in Boulder County when soil has warmed and frost danger has passed.
Boulder County receives only 22" of rain annually. Bleeding Hearts needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Plant bare-root crowns in early spring as soon as soil is workable, or in fall at least 6 weeks before hard freeze. Set eyes 1–2 inches below soil level. Morning sun with afternoon shade is ideal; deep shade is tolerated but reduces bloom. Keep moist but well-drained — will not tolerate waterlogged soil. After flowering, the foliage will yellow and die back in summer heat — this is normal. Do not cut back until foliage turns fully yellow; the plant is storing energy. Mark the location to avoid disturbing crowns during summer dormancy. Divide every 4–5 years in early spring. Year 2+ plants produce the fullest flowering display.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Bleeding Hearts in Other Locations
Frequently Asked Questions
When should I plant Bleeding Hearts in Boulder County, CO?
Boulder County is in Zone 6a with an average last frost of May 14. Plan your Bleeding Hearts planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boulder County, CO?
Boulder County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.
When should I plant Bleeding Hearts in Boulder County, CO?
In Boulder County, CO, plant Bleeding Hearts after the last frost (around May 14) and before the first frost (around September 26). Best results when soil holds above 50°F.
What growing zone is Boulder County, CO for Bleeding Hearts?
Boulder County sits in USDA Zone 6a. Bleeding Hearts grows reliably in zones 3a through 9a, so it's a good fit here.
Can Bleeding Hearts grow in Boulder County's climate?
Yes — Bleeding Hearts grows well in Boulder County's temperate climate. Boulder County averages a 135-day frost-free season, with last frost around May 14 and first frost around September 26.
Your Boulder County Garden Planner — Free
A 22-page printable planner built for Boulder County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.