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When to Plant Hyssop in Jefferson County, OR

Jefferson County, Oregon Zone 7a June

Your June game plan for Jefferson County, Oregon

June is a pivotal month for Jefferson County, Oregon gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 9
Avg. first frost September 19
Soil temp (4") 74°F
Watering High
Pest pressure High
Daylight 15.4 hrs
  1. Move hyssop from tray to bed

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.

Jefferson County, Oregon is in USDA Zone 7a. The average last spring frost is June 9 and the first fall frost is September 19, giving you a growing season of approximately 102 days.

At an elevation of 21 feet, Jefferson County receives approximately 36.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Hyssop to ensure they mature before fall.

Jefferson County, OR (Zone 7a) Short season
102 days
Last Spring Frost June 9
102 growing days
First Fall Frost September 19

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Hyssop Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Aug 15 – Oct 17
Recommended (50%) ✗ May not fit
Transplant: Jun 16 🍅 Harvest: Aug 25 – Oct 27
Safe Start (90%) ✗ May not fit
Transplant: Jun 29 🍅 Harvest: Sep 7 – Nov 9

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 Jefferson County

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

Soil pH

Your soil pH (5.3–6.7) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Hyssop will thrive.

How to Plant Hyssop

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

Hyssop Water Budget

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

Monthly Watering Guide for Hyssop

Hyssop 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 Hyssop Needs Rainfall You Supplement Action
Jan 4.8" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 1.8" 0" ❄️ Dormant
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 0.5" 1.7" 🚿 Regular watering
Aug 2.2" 0.6" 1.6" 🚿 Regular watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 3.2" 0" ❄️ Dormant
Nov 6.1" 0" ❄️ Dormant
Dec 5.5" 0" ❄️ Dormant

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

Hyssop 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.

Hyssop needs ~740 GDD — county provides 943 GDD Good fit

Hyssop Planting Timeline — Jefferson County, OR

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors June 16 Jun 16 – Jun 30
Harvest August 25 Aug 25 – Oct 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

102 days in Jefferson County

Growing Tips for Hyssop in Jefferson County

Direct sow Hyssop outdoors after June 09 in Jefferson County when soil has warmed and frost danger has passed.

Your 102.0-day growing season in Jefferson County is tight for Hyssop (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.

Companion Planting

Good Companions

Avoid Planting Near

  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyssop in Jefferson County, OR?

Jefferson County is in Zone 7a with an average last frost of June 9. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, OR?

Jefferson County, Oregon is in USDA Hardiness Zone 7a. The average last spring frost is June 9 and first fall frost is September 19.

🌱

Your Jefferson County Garden Planner — Free

A 22-page printable planner built for Jefferson County (Zone 7a). 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 Jefferson County, OR. 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.