When to plant Larkspur in Putnam County, IL
Putnam County sits in USDA Zone 5b. Plant Larkspur between March 24 (after last frost on April 21) and April 14.
When to Plant Larkspur in Putnam County, IL
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.
Putnam County, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.
At an elevation of 582 feet, Putnam County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Larkspur during the growing season.
Putnam County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Larkspur Planting Timeline — Putnam County, IL
Larkspur Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 24 | Mar 24 – Apr 14 |
| Bloom | June 2 | Jun 2 – Jul 28 |
Plant 0.1" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Direct Sow |
| May | — |
| June | Bloom |
| July | Bloom |
| August | — |
| 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
175 days in Putnam County
Growing Tips for Putnam 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 Putnam County, IL?
Putnam County is in Zone 5b with an average last frost of April 21. Plan your Larkspur planting based on this frost date — see the calendar above for exact timing.
What planting zone is Putnam County, IL?
Putnam County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.
When should I plant Larkspur in Putnam County, IL?
In Putnam County, IL, plant Larkspur after the last frost (around April 21) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Putnam County, IL for Larkspur?
Putnam 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 Putnam County's climate?
Yes — Larkspur grows well in Putnam County's temperate climate. Putnam County averages a 175-day frost-free season, with last frost around April 21 and first frost around October 13.
Your Putnam County Garden Planner — Free
A 22-page printable planner built for Putnam 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.