When to Plant Hyssop in Caldwell County, TX
May in Caldwell County, Texas — your action list
We've pulled the most time-sensitive tasks for Caldwell County, Texas this May and put them front and centre. Tackle them in order.
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Basket week: hyssop
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
June will be here before you know it — start on
- First harvests: hyssop
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.
Caldwell County, Texas is in USDA Zone 9a. The average last spring frost is February 27 and the first fall frost is December 1, giving you a growing season of approximately 277 days.
At an elevation of 3,482 feet, Caldwell County receives approximately 60.8 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Hyssop during the growing season. Clay soil retains moisture well for Hyssop, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Hyssop root diseases.
Caldwell County Soil Profile
Soil Type
Clay
Soil pH
6.8-8.1
Drainage
Well Drained
Plant Planting Risk Windows
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 Caldwell County
How your county's soil matches Hyssop's growing requirements.
Soil pH
Your soil pH (6.8–8.1) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.
Soil Texture
Heavy clay soil (43% clay) in Caldwell County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Hyssop.
How to Plant Hyssop
Succession Planting Hyssop
Sow every 8 weeks. Last sowing by Sep 02 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | 2.2" | 2.1" | 0.1" | 💧 Light watering |
| Mar | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 9.9" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 9.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 7.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 5.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Dec | 2.2" | 1.5" | 0.7" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in Caldwell 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 Planting Timeline — Caldwell County, TX
Hyssop Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 6 | Mar 6 – Mar 20 |
| Harvest | May 15 | May 15 – Jul 17 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| 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 9a
📆 Growing Season
277 days in Caldwell County
Growing Tips for Hyssop in Caldwell County
Direct sow Hyssop outdoors after February 27 in Caldwell County when soil has warmed and frost danger has passed.
With Caldwell County's clay soil (43% clay), work in 3-4 inches of compost before planting Hyssop. Avoid tilling when soil is wet to prevent compaction.
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
Check more plant combinations with our Companion Planting Checker →
Hyssop in Other Locations
Frequently Asked Questions
When should I plant Hyssop in Caldwell County, TX?
Caldwell County is in Zone 9a with an average last frost of February 27. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.
What planting zone is Caldwell County, TX?
Caldwell County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 27 and first fall frost is December 1.
Your Caldwell County Garden Planner — Free
A 24-page printable planner built for Caldwell County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.