When to plant Larkspur in Custer County, CO
In Custer County, Larkspur is a spring-only crop. Plant April 25–May 16 once soil hits 50°F.
When to Plant Larkspur in Custer County, CO
Larkspur (Consolida ajacis) is a cool-season annual that produces tall, delicate spires of blue, purple, pink, and white flowers reminiscent of its perennial cousin, delphinium. Direct-sown into cold soil or fall-sown in mild-winter climates, it blooms in spring before going to seed as summer heat arrives. An excellent cut flower and cottage-garden staple.
Custer County, Colorado is in USDA Zone 5b. The average last spring frost is May 23 and the first fall frost is September 25, giving you a growing season of approximately 125 days.
At an elevation of 8,115 feet, Custer County receives approximately 18.1 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Larkspur during the growing season. With low rainfall, drip irrigation is essential for growing Larkspur successfully. Mulch heavily to conserve soil moisture.
Custer County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Larkspur Planting Timeline — Custer County, CO
Larkspur Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 25 | Apr 25 – May 16 |
| Bloom | July 4 | Jul 4 – Aug 29 |
Plant 0.1" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
125 days in Custer County
Growing Tips for Custer County
Larkspur does not transplant well — direct-sow only. In cold climates (zones 2–6), sow directly in early spring as soon as soil can be worked, 4–6 weeks before last frost; cold soil improves germination. In zones 7–10, fall-sow 8–10 weeks before first frost for spring bloom. Press seeds lightly into soil; they need darkness to germinate — cover with 1/8–1/4 inch of soil. Thin to 6–12 inches to prevent powdery mildew. Allow seed pods to mature and self-sow for naturalized colonies. All parts are toxic if ingested.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Larkspur in Other Locations
Frequently Asked Questions
When should I plant Larkspur in Custer County, CO?
Custer County is in Zone 5b with an average last frost of May 23. Plan your Larkspur planting based on this frost date — see the calendar above for exact timing.
What planting zone is Custer County, CO?
Custer County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 23 and first fall frost is September 25.
When should I plant Larkspur in Custer County, CO?
In Custer County, CO, plant Larkspur after the last frost (around May 23) and before the first frost (around September 25). Best results when soil holds above 50°F.
What growing zone is Custer County, CO for Larkspur?
Custer County sits in USDA Zone 5b. Larkspur grows reliably in zones 2a through 10b, so it's a good fit here.
Can Larkspur grow in Custer County's climate?
Yes — Larkspur grows well in Custer County's temperate climate. Custer County averages a 125-day frost-free season, with last frost around May 23 and first frost around September 25.
Your Custer County Garden Planner — Free
A 22-page printable planner built for Custer 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.