Unlikely — Zone Mismatch
agastache (zones 6-9) does not overlap with South Dakota's zone range (4a-5b). Growing outdoors is unlikely without significant protection.
One zone short — what would close it
Agastache is hardy to zone 6, and the warmest ground in South Dakota is zone 5 — 1 zone short. Planted in open ground it will not survive a South Dakota winter. To grow it here, grow agastache in a hoop house or unheated greenhouse — its modeled 1.5-zone lift covers this gap.
A hoop house or unheated greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 6-9 (plant) against 4-5 (South Dakota). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['hoop_house'] (+1.5 zones) via api/fast_sections.py Unlock Engine v2.
Agastache in South Dakota — the short answer
Agastache in South Dakota: hardy in zones 6–9, full sun, against a state median of ~168 frost-free days.
- Plant zones
- 6-9
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- South Dakota zones
- 4a-5b
- USDA PHZM 2023
- Frost window
- Apr 22 - Apr 29 – Oct 9 - Oct 15
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 145 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
South Dakota spans zones 4a-5b, 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 agastache against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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South Dakota is not one climate
South Dakota’s winter-low ladder runs across 66 counties, from zone 4 in Brown County to zone 5.5 in Custer County. That is 15°F between the two counties’ average coldest night — the difference between agastache overwintering in the ground and coming under cover.
The middle half of 66 counties runs 4.5–5 zones, with a median of 4.5 zones — a 1.5-zone span end to end.
Measured across 66 South Dakota counties. USDA PHZM 2023, per county. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where Agastache Stands in South Dakota
Agastache is rated for zones 6–9 — a cold floor USDA puts at -10 to 0°F. No South Dakota county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about South Dakota winters, not about agastache.
Below the zone 6 floor
66 counties
- Brown County · zone 4a
- Marshall County · zone 4a
- Beadle County · zone 4b
3 of 66 shown
Winter cold is the limit here — the same plant works in a container that comes under cover.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.
Zone Comparison
Agastache Needs
- USDA Zones: 6-9
- Sun: Full Sun
- Mature size: 3 ft tall
- Picking window: ~60 days of harvest
- Drought tolerance: High
South Dakota Has
- USDA Zones: 4a-5b
- Last Hard Freeze (28°F): Apr 22 - Apr 29
- First Hard Freeze (28°F): Oct 9 - Oct 15
- Annual Rainfall: 14-26 inches
- Common Soils: Prairie loam, Clay, Sandy loam
Plant Zone Range (zones 6-9)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Agastache in South Dakota
The frost window
Across South Dakota, the last spring hard freeze (28°F) clears between Apr 22 and Apr 29, and the first fall hard freeze lands between Oct 9 and Oct 15 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 163-day window you can count on — up to 176 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.
Winter standing
South Dakota runs as cold as USDA zone 4, and no sourced winter-hardiness floor is on record for agastache, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether agastache is a permanent planting or a replant-every-spring crop for you turns on your own zone within South Dakota; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Lawrence County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Soil + Drainage Fit
Agastache likes near-neutral soil (pH 6-7.5). That's the common-ground band across South Dakota's prairie loam and clay — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6.5 and 7.5 — worth knowing before you decide whether a South Dakota soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your South Dakota site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
South Dakota's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for agastache is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how agastache performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. South Dakota soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Agastache in South Dakota
Zone compatibility tells you about winter cold survival — but South Dakota growers also need to think about:
Extreme cold and short growing season
Low rainfall in western SD
Wind exposure on the open prairie
Growing agastache here specifically
South Dakota's soils run mostly loam (Mollisols), and whether that suits agastache's pH 6.0–7.5 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward agastache's 6.0–7.5 target before planting. How to handle it →
What to actually do about these — and the constraints that apply to every South Dakota grower, not just agastache — is covered on the South Dakota growing guide.
Timing shifts within South Dakota
South Dakota isn't one climate. In Lawrence County, the last hard freeze (28°F) holds until about May 12 — roughly 17 days later than the recorded state median — so plant agastache to your county's window, not the statewide date.
County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Where in South Dakota Agastache Is Zone-Hardy
Agastache is rated for USDA zones 6–9. No South Dakota county reaches it. Even Custer County, the state’s mildest winter at zone 5b, sits below the plant’s zone 6 floor — so in open ground this one needs winter protection here, or a container that comes under cover.
Across those 66 counties South Dakota’s winter-low ladder runs from zone 4a in Brown County to zone 5b in Custer County — 1.5 USDA zones of spread, which is 15°F between the two counties’ average coldest night of the year. None of that range reaches the band agastache needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Agastache’s zone 6–9 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Agastache draws honeybees, native bees, butterflies, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, agastache can only work that bloom inside South Dakota's frost window — roughly 168 days, opening after the last 28°F freeze (Apr 22 - Apr 29) and closing at the first (Oct 9 - Oct 15), per NOAA Regional Climate Centers ACIS, 1991-2020.
Recommended Agastache Varieties for South Dakota
South Dakota publishes no state variety trial for agastache, so we won't invent a "best for South Dakota" list. Choose types rated to your USDA hardiness zone (4a-5b), and confirm winter survival and drainage against your own parcel.
South Dakota Cooperative Extension
For South Dakota-specific cultivar recommendations, planting calendars, and pest pressure for agastache, the canonical source is SDSU Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Agastache in South Dakota
When can I plant Agastache in South Dakota?
South Dakota's last spring hard freeze (28°F) clears between Apr 22 and Apr 29, and the first fall hard freeze lands between Oct 9 and Oct 15 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Agastache, so this page does not state whether it overwinters in South Dakota and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Agastache grown in across South Dakota?
South Dakota spans USDA hardiness zones 4a-5b (USDA ARS PHZM 2023). Agastache carries a range of zones 6-9, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical South Dakota site have?
A typical South Dakota site sees ~168 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Agastache should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Lawrence, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Agastache in South Dakota?
Agastache prefers pH 6-7.5 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across South Dakota soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Agastache actually grow on my specific land in South Dakota?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores agastache 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 South Dakota
State-level data is a sketch. Your Growable Ground report scores agastache against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that South Dakota agastache averages can't show:
We read public map data around South Dakota — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the South Dakota agastache average
Explore More
Growing guides for agastache
Explore South Dakota county by county
South Dakota carries 66 counties with their own USDA zone — a sample of the growing pages for agastache there:
Where else agastache grows
Agastache's zone band crosses state lines — these are the states closest to South Dakota in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in South Dakota
South Dakota has a growing page for 747 plants — a rotating sample of the rest of the shelf.
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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