Growing Regions

The eight regions

Region	Climate in one line	States (main)
Pacific Northwest	Wet winters, mild summers	Western WA and OR
California	Dry summers, mild wet winters	CA (except the southeast desert)
Intermountain West	High desert: sun, wind and late frosts	ID, NV, UT, MT, WY, CO, eastern WA and OR
Desert Southwest	Intense sun and heat, very little rain	AZ, NM, far west TX, southeastern CA
Great Plains	Wind, cold snaps and swings	ND, SD, NE, KS, OK, north and central TX
Midwest & Great Lakes	Freeze-thaw winters, humid summers	MN, WI, MI, IA, IL, IN, OH, MO
Northeast	Snowy dormancy, cool springs	ME, NH, VT, MA, CT, RI, NY, NJ, PA, AK
Southeast	Heat, humidity and heavy rain	DE, MD, VA, WV, KY, TN, the Carolinas, GA, FL, AL, MS, LA, AR, HI, DC, east Texas

The plot report adds up risk points from your site:

Zone 4 or colder: Hard winters (+2).
Coldest temperature of −15°F or lower in a warmer zone: Deep cold snaps (+1).
45 or more inches of rain a year, or lots of winter rain without well-drained soil: Wet ground (+2).
Summer humidity of 70% or more with real heat: Humid summers (+1).
60 or more days at 90°F: Long heat (+1).
Less than 15 inches of rain: Dry climate (a note, no risk).
Mapped soil draining under 60%: Slow-draining soil (+2); otherwise Good drainage.

Risk points	Grade	Message
0–1	🌟 Excellent	Lavender should thrive here with basic care.
2–3	👍 Good	Very workable — a few site fixes make a big difference.
4 or more	💪 Challenging	Doable with the right site prep and cultivars. The simulator will show you where it bites.

Zone	Suggested starting point
5 or colder	Hardy English lavender (Munstead, Hidcote, Phenomenal)
6–7	English lavender plus lavandins (Grosso, Phenomenal) for oil and bundles
8–9	Lavandins and heat-tolerant types (Grosso, Provence, Phenomenal); Spanish lavender for color
10 or warmer	Spanish and French lavender; treat English types as short-lived