Generally — Most Areas
hyssop (zones 3-9) suits most of Texas (6b-10b) — zones 6-9 are in range, and the rest of the state is the exception.
Your yard isn't the whole zone.
Texas spans zones 6b-10b, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score hyssop against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Hyssop Needs
- USDA Zones: 3-9
- Frost-Free Days: 180+
- Sun: Part Sun
- Mature size: 2 ft tall
- Picking window: ~90 days of harvest
- Drought tolerance: Medium
Texas Has
- USDA Zones: 6b-10b
- Last Hard Freeze (28°F): Feb 10 - Mar 12
- First Hard Freeze (28°F): Nov 18 - Dec 4
- Annual Rainfall: 8-56 inches
- Common Soils: Black clay (Blackland Prairie), Sandy loam, Caliche
Plant Zone Range (zones 3-9)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Hyssop in Texas
The frost window
Across Texas, the last spring hard freeze (28°F) clears between Feb 10 and Mar 12, and the first fall hard freeze lands between Nov 18 and Dec 4 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 251-day window you can count on — up to 297 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
When to start the seed
Those dates are when hyssop goes out, not when it starts. It is sown under cover about 8 weeks ahead, so counting back from Texas's late-side last freeze of Mar 12 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Establishment timing
As a long-lived plant, hyssop isn't racing the calendar to a harvest date. Plant it in spring once the last hard-freeze window passes so roots settle in through the full season, or in early fall while the soil still holds summer warmth.
Timing tuned to sub-state frost dates — Dallam County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says hyssop survives winter in part of Texas, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Hyssop wants 180+ frost-free days; a typical Texas site sees ~274 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Hyssop needs ~900 GDD (base 50°F) to ripen. The state median runs ~5834 GDD (from PRISM 1991-2020 climate normals), so Texas's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Hyssop tolerates a wide pH range (pH 5.5-8.5) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Texas. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 6 and 7.5 — worth knowing before you decide whether a Texas soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells), excessive (dry/moderately dry). If your Texas site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Texas's soils run mostly fine sandy loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Hyssop needs about 19 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how hyssop performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Texas soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Hyssop in Texas — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 3-9 (USDA PLANTS Database)
- State Zones: 6b-10b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Feb 10 - Mar 12 to Nov 18 - Dec 4 (NOAA Regional Climate Centers ACIS, 1991-2020)
- Days to Maturity: 85 days
What Else to Consider for Hyssop in Texas
Zone compatibility tells you about winter cold survival — but Texas growers also need to think about:
Extreme heat (100F+ days) stresses many crops from June through September
Rainfall varies dramatically — 8 inches in west TX to 56 inches in east TX
Heavy black clay (Blackland Prairie) is difficult to work and drains poorly
Flash drought conditions can develop rapidly even in wet years
Growing hyssop here specifically
Hyssop sends medium roots and rates to zones 3–9, but much of Texas sits on slow-draining, restrictive ground (SSURGO hydrologic group D) that forks and stunts them.
Loosen a deep, stone-free bed for hyssop and break any compacted or hardpan layer before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Texas grower, not just hyssop — is covered on the Texas growing guide.
Timing shifts within Texas
Texas isn't one climate. In Dallam County, the last hard freeze (28°F) holds until about Apr 12 — roughly 46 days later than the recorded state median — so plant hyssop to your county's window, not the statewide date.
Hyssop needs about 180 days of frost-free season to complete its cycle. Even Dallam County — Texas’s shortest season at 197 frost-free days — clears that by 17 days, so season length isn’t the constraint anywhere in Texas. What varies is your own parcel.
Across Texas’s 254 counties the frost-free season runs from 197 days in Dallam County to 343 days in Kenedy County — a spread of 146 days, which is why a single statewide planting date misleads. The median Texas county sees 274 frost-free days, leaving hyssop about 94 days of slack on a typical parcel — room for a second sowing where the season runs long.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Hyssop's 180-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Where in Texas Fits Best
Even within Texas's zones 6b-10b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for hyssop (USDA PHZM 2023):
Pollinator + Wildlife Value
Hyssop draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, hyssop can only work that bloom inside Texas's frost window — roughly 274 days, opening after the last 28°F freeze (Feb 10 - Mar 12) and closing at the first (Nov 18 - Dec 4), per NOAA Regional Climate Centers ACIS, 1991-2020.
Recommended Hyssop Varieties for Texas
Texas publishes no state variety trial for hyssop, so we won't invent a "best for Texas" list. Choose types rated to your USDA hardiness zone (6b-10b), and confirm winter survival and drainage against your own parcel.
Texas Cooperative Extension
For Texas-specific cultivar recommendations, planting calendars, and pest pressure for hyssop, the canonical source is Texas A&M AgriLife Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Hyssop native to Texas?
No — the USDA PLANTS Database lists Hyssop as introduced rather than native in the Lower 48, so it is not part of Texas's native flora. It grows here as a garden plant; pairing it with a few Texas natives keeps local pollinators fed too.
Looking for plants that belong here? The Texas growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Hyssop in Texas
When can I plant Hyssop in Texas?
Texas's last spring hard freeze (28°F) clears between Feb 10 and Mar 12, and the first fall hard freeze lands between Nov 18 and Dec 4 (NOAA Regional Climate Centers ACIS, 1991-2020). Hyssop is a long-lived planting, so target spring just after your local last hard freeze — or early fall while the soil holds warmth — and let it establish through the season.
What hardiness zone is Hyssop grown in across Texas?
Texas spans USDA hardiness zones 6b-10b (USDA ARS PHZM 2023). Hyssop carries a range of zones 3-9, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Texas site have?
A typical Texas site sees ~274 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Hyssop needs 180+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Dallam, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Hyssop native to Texas?
No — the USDA PLANTS Database lists Hyssop as introduced rather than native in the Lower 48, so it is not part of Texas's native flora. It grows here as a garden plant; pairing it with a few Texas natives keeps local pollinators fed too.
How should I amend the soil for Hyssop in Texas?
Hyssop tolerates pH 5.5-8.5 and well (dry spells), excessive (dry/moderately dry) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Texas site — amend for drainage and organic matter first.
Will Hyssop actually grow on my specific land in Texas?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores hyssop against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Texas
State-level data is a sketch. Your Growable Ground report scores hyssop against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Texas hyssop averages can't show:
We read public map data around Texas — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Texas hyssop average
Explore More
Growing guides for hyssop
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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