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When to plant Larkspur in Lyon County County,

Plant Larkspur in Lyon County County after May 2; the prime window is April 4–April 25.

When to Plant Larkspur in Lyon County, IA

Lyon County, Iowa Zone 5a June

Your June game plan for Lyon County, Iowa

Your Lyon County, Iowa garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 2
Avg. first frost October 2
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
  1. Bring in the larkspur

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Before July arrives, get these ready
  • First harvests: larkspur

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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.

Lyon County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 2, giving you a growing season of approximately 153 days.

At an elevation of 1,045 feet, Lyon County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Larkspur to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Lyon County, IA (Zone 5a) Moderate season
153 days
Last Spring Frost May 2
153 growing days
First Fall Frost October 2

Lyon County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Larkspur Planting Risk Windows

Early Start (70% safe) ✓ Fits season (25 days to spare)
Transplant: Apr 27 🌸 Bloom: Jul 6 – Aug 31
Recommended (50%) ✓ Fits season (27 days to spare)
Transplant: May 2 🌸 Bloom: Jul 11 – Sep 5
Safe Start (90%) ✓ Fits season (24 days to spare)
Transplant: May 16 🌸 Bloom: Jul 25 – Sep 19

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 Lyon County

How your county's soil matches Larkspur's growing requirements.

Soil pH

Your soil pH (6.3–6.8) is within Larkspur's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Lyon County is excellent for Larkspur — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.6%) — Larkspur will thrive.

How to Plant Larkspur

0.1"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Larkspur

2
successive plantings in your 153-day season

Sow every 6.9 weeks. Last sowing by Jul 04 to harvest before frost.

Larkspur Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Larkspur

Larkspur 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 Larkspur Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 2.2" 3" 0" ✅ Rainfall sufficient
Jun 2.2" 4.2" 0" ✅ Rainfall sufficient
Jul 2.2" 3.7" 0" ✅ Rainfall sufficient
Aug 2.2" 2.7" 0" ✅ Rainfall sufficient
Sep 2.2" 2.3" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 2.1" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Lyon County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Larkspur 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.

Larkspur needs ~750 GDD — county provides 1,530 GDD Excellent fit

Larkspur Planting Timeline — Lyon County, IA

Larkspur Planting Calendar

Activity When Date Range
Direct Sow April 4 Apr 4 – Apr 25
Bloom June 13 Jun 13 – Aug 8

Plant 0.1" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May
June Bloom
July Bloom
August Bloom
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

153 days in Lyon County

Growing Tips for Larkspur in Lyon County

Direct sow Larkspur outdoors after May 02 in Lyon County when soil has warmed and frost danger has passed.

General growing tips

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 →

Frequently Asked Questions

When should I plant Larkspur in Lyon County, IA?

Lyon County is in Zone 5a with an average last frost of May 2. Plan your Larkspur planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lyon County, IA?

Lyon County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 2.

When should I plant Larkspur in Lyon County County, ?

In Lyon County County, , plant Larkspur after the last frost (around May 2) and before the first frost (around October 2). Best results when soil holds above 50°F.

What growing zone is Lyon County County, for Larkspur?

Lyon County County sits in USDA Zone 5a. Larkspur grows reliably in zones 2a through 10b, so it's a good fit here.

Can Larkspur grow in Lyon County County's climate?

Yes — Larkspur grows well in Lyon County County's temperate climate. Lyon County County averages a 153-day frost-free season, with last frost around May 2 and first frost around October 2.

🌱

Your Lyon County Garden Planner — Free

A 22-page printable planner built for Lyon 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.

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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 Lyon County, IA. 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.