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When to Plant Haskaps in Boulder County, CO

Haskaps (honeyberries) are extremely cold-hardy shrubs producing elongated blue berries with a complex blueberry-raspberry flavor. They fruit very early in the season.

Boulder County, Colorado is in USDA Zone 5b. 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 86ยฐF, providing good warmth for Haskaps during the growing season.

Boulder County, CO (Zone 5b) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Boulder County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 24
Recommended (50%) ✓ Fits season
Transplant: Jun 4
Safe Start (90%) ✓ Fits season
Transplant: Jul 1

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 Boulder County

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

Soil pH

Your soil pH (6.7โ€“8.0) overlaps with Haskaps's range (5.5โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Boulder County is excellent for Haskaps โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Haskaps.

Organic Matter

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

How to Plant Haskaps

48"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 879 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Haskaps

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

Month Haskaps Needs Rainfall You Supplement Action
Jan โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.3" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr โ€” 2.2" 0" โ„๏ธ Dormant
May 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Jun 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Jul 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Aug 4.3" 2.1" 2.2" ๐Ÿšฟ Regular watering
Sep 4.3" 2.1" 2.2" ๐Ÿšฟ Regular watering
Oct โ€” 1.9" 0" โ„๏ธ Dormant
Nov โ€” 1.4" 0" โ„๏ธ Dormant
Dec โ€” 1.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Boulder County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Haskaps 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" โ€” every day above 50ยฐF 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.

Haskaps needs ~13,231 GDD — county provides 1,957 GDD May not mature

Haskaps Planting Timeline โ€” Boulder County, CO

Haskaps Planting Calendar

Activity When Date Range
Transplant Outdoors June 4 Jun 4 โ€“ Jun 18

ยท 48" apart ยท Rows 72" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Transplant Outdoors
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

730โ€“1095 days

๐Ÿงช Soil pH

Needs 5.5โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

135 days in Boulder County

Growing Tips for Haskaps in Boulder County

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

Your 135.0-day growing season in Boulder County is tight for Haskaps (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Plant at least two different varieties for cross-pollination. Fruits ripen 2-3 weeks before strawberries. Protect from birds. Very low maintenance once established. Tolerates extreme cold.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Haskaps in Boulder County, CO?

Boulder County is in Zone 5b with an average last frost of May 14. Plan your Haskaps planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Boulder County, CO?

Boulder County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 14 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Boulder County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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: April 2026.