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When to plant Snapdragon in Custer County, ID

In Custer County, Snapdragon is a spring-only crop. Plant June 4–June 25 once soil hits 50°F.

When to Plant Snapdragon in Custer County, ID

Snapdragons (Antirrhinum majus) are classic cool-season annuals whose upright spikes of dragon-lipped flowers are among spring's most dramatic displays. Tolerating light frosts, they bloom from early spring until summer heat shuts them down — then often revive in fall. In zones 9-11 they are grown as fall-planted winter annuals and may re-seed to naturalize.

Custer County, Idaho is in USDA Zone 5b. The average last spring frost is June 18 and the first fall frost is September 5, giving you a growing season of approximately 79 days.

At an elevation of 5,189 feet, Custer County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Snapdragon to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Custer County, ID (Zone 5b) Very short season
79 days
Last Spring Frost June 18
79 growing days
First Fall Frost September 5

Custer County Soil Profile

Soil Type

Loam

Soil pH

6.3-8

Drainage

Well Drained

Monthly Watering Guide for Snapdragon

Snapdragon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Snapdragon Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 2.3" 0" ❄️ Dormant
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Snapdragon Planting Timeline — Custer County, ID

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 4 Jun 4 – Jun 25
Bloom August 27 Aug 27 – Nov 5

· 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6.2–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

79 days in Custer County

Growing Tips for Custer County

Start indoors 10-12 weeks before last frost; seeds need light to germinate — press into moist medium and do not cover. Transplant after hardening off, even if light frosts remain. Pinch seedlings once to encourage branching. Deadhead to prolong blooming. In zones 8-11, sow in fall for a winter-to-spring show. Tall varieties (24-36") make excellent cut flowers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Snapdragon in Custer County, ID?

Custer County is in Zone 5b with an average last frost of June 18. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Custer County, ID?

Custer County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 18 and first fall frost is September 5.

When should I plant Snapdragon in Custer County, ID?

In Custer County, ID, plant Snapdragon after the last frost (around June 18) and before the first frost (around September 5). Best results when soil holds above 50°F.

What growing zone is Custer County, ID for Snapdragon?

Custer County sits in USDA Zone 5b. Snapdragon grows reliably in zones 2a through 11b, so it's a good fit here.

Can Snapdragon grow in Custer County's climate?

Yes — Snapdragon grows well in Custer County's temperate climate. Custer County averages a 79-day frost-free season, with last frost around June 18 and first frost around September 5.

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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.

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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 Custer County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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