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When to plant Feverfew in Lyons, CO

Lyons's 135-day season only supports one Feverfew planting per year. Sow between May 21 and June 4 for the best chance at full maturity before September 26.

When to Plant Feverfew in Lyons, CO

Boulder County, Colorado Zone 6a June

This month in Boulder County, Colorado

Your garden in Boulder County, Colorado is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost May 14
Avg. first frost September 26
Soil temp (4") 46°F
Watering High
Pest pressure High
Daylight 14.8 hrs

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Feverfew is a bushy perennial herb with small daisy-like flowers and aromatic leaves. It has been used traditionally for headache relief and is a cheerful garden plant.

Lyons, 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 Feverfew during the growing season.

Lyons, CO (Zone 6a) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Lyons Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Feverfew Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 10 🍅 Harvest: Aug 9 – Oct 25
Recommended (50%) ✗ May not fit
Transplant: May 21 🍅 Harvest: Aug 20 – Nov 5
Safe Start (90%) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Sep 16 – Dec 2

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 Lyons

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

Soil pH

Your soil pH (6.7–8.0) is more alkaline than Feverfew prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Boulder County is excellent for Feverfew — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Feverfew.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Feverfew.

How to Plant Feverfew

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Feverfew Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 Feverfew

Feverfew 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 Feverfew 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 2.2" 3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 2" 0.2" 💧 Light watering
Aug 2.2" 2.1" 0.1" 💧 Light watering
Sep 2.2" 2.1" 0.1" 💧 Light 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.

Feverfew 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.

Feverfew needs ~1,522 GDD — county provides 1,957 GDD Good fit

Feverfew Planting Timeline — Lyons, CO

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors May 21 May 21 – Jun 4
Harvest August 20 Aug 20 – Nov 5

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
November Harvest
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

135 days in Boulder County

Growing Tips for Feverfew in Lyons

Direct sow Feverfew outdoors after May 14 in Boulder County when soil has warmed and frost danger has passed.

Common pests for Feverfew in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Boulder County receives only 22" of rain annually. Feverfew needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors or direct sow on the soil surface. Deadhead regularly to prevent aggressive self-seeding. Divide clumps every 2-3 years to maintain vigor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Feverfew in Lyons, CO?

In Lyons, CO, plant Feverfew 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 Lyons, CO for Feverfew?

Lyons sits in USDA Zone 6a. Feverfew grows reliably in zones 5a through 9b, so it's a good fit here.

Can Feverfew grow in Lyons's climate?

Yes — Feverfew grows well in Lyons's temperate climate. Lyons averages a 135-day frost-free season, with last frost around May 14 and first frost around September 26.

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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.

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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 Boulder County, CO. Local conditions may vary. Last updated: June 2026.