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Plants

Magnolia planting zones

Magnolia covers 4a–10b, but the zone is only half the answer. Of the 6 types below, 3 carry their flower display through the spring freeze window and 3 do not. That difference decides whether a late freeze costs you a season of flowers.

The types

Which magnolia you are choosing between

Type Zones A late freeze
Star magnolia Magnolia stellata 4a to 8b, then too hot Exposed The earliest of the common magnolias, which is exactly why it is the most often browned.
Saucer magnolia Magnolia × soulangeana 4b to 9a, then too hot Exposed Opens on bare wood before the leaves. The classic pink display, and the classic frost loss.
Loebner magnolia Magnolia × loebneri 4a to 8b, then too hot Exposed A star hybrid, marginally later than its parent but still inside most spring freeze windows.
Sweetbay magnolia Magnolia virginiana 5a to 10a, then too hot Safe A US native that flowers after leaf-out, and tolerates wet ground the others will not.
Southern magnolia Magnolia grandiflora 6b to 10b, then too hot Safe Evergreen, and flowers from late spring into summer — long after the freeze window shuts.
Cucumbertree magnolia Magnolia acuminata 4a to 8b, then too hot Safe A large native shade tree whose green flowers open with the leaves and are easily missed.

Zone ranges and bloom habit are a judgement — horticultural convention, not a measurement, and the same standing as the heat ratings on our crop tables. Everything below this panel is measured.

Zone by zone

Which magnolias are hardy where, and when the freeze lands

The two left columns come from the variety table above — a judgement. The two right columns are measured: they are the median last spring freeze across every NOAA station the zone’s ZIP codes actually cite, and how much later the one-year-in-ten freeze arrives.

Zone Hardy here Flowers exposed Last spring freeze 1 year in 10
4a 3 of 6 2 May 6 – May 27 across 298 stations about 14 days later
4b 4 of 6 3 May 2 – June 1 across 477 stations about 14 days later
5a 5 of 6 3 April 28 – May 31 across 718 stations about 14 days later
5b 5 of 6 3 April 22 – May 28 across 752 stations about 15 days later
6a 5 of 6 3 April 18 – May 24 across 1004 stations about 16 days later
6b 6 of 6 3 April 11 – May 19 across 991 stations about 16 days later
7a 6 of 6 3 April 5 – May 9 across 941 stations about 17 days later
7b 6 of 6 3 March 30 – April 26 across 679 stations about 16 days later
8a 6 of 6 3 March 20 – April 16 across 689 stations about 17 days later
8b 6 of 6 3 March 7 – April 17 across 700 stations about 19 days later
9a 3 of 6 1 February 15 – April 6 across 446 stations about 22 days later
9b 2 of 6 none February 2 – April 6 across 218 stations about 27 days later
10a 2 of 6 none 152 of 190 stations here record no ordinary spring freeze, so no date speaks for the zone
10b 1 of 6 none 68 of 79 stations here record no ordinary spring freeze, so no date speaks for the zone

“Hardy here” and “flowers exposed” are a judgement, from the variety table above. The freeze dates are measured — NOAA 1991–2020 climate normals, and the range is across the stations the zone’s own ZIP codes cite rather than one station chosen to speak for it.

Why the date matters

Your zone does not tell you your last freeze

Across the 12 zones above that publish a range, the median last spring freeze varies by 36 days inside a single zone — 21 days even in the tightest, zone 4a, and 63 in the widest, zone 9b. Two gardens with the same zone on the label can be a month apart on the date that decides whether magnolias flower.

And the median is not the risk. Across the 6,130 NOAA stations serving these zones, the freeze that arrives one year in ten lands a median of 16 days after the median date, and 22 days after it at the tenth of stations where that tail runs longest. A variety marked exposed above is standing in front of that whole window, not in front of one date.

⛔ We publish no temperature at which a bud is lost. NOAA’s normals give dates, not damage thresholds, and inventing a number to bridge the two is the one thing this site refuses everywhere else. What is on this page is when the freeze arrives and which flowers are out when it does.

Your ZIP code

Get the exact answer for your address

Everything above describes magnolias across the United States as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.

Works for all 40,502 US ZIP codes. Freeze dates need a NOAA station within 100 km; where there is none, the page says so rather than estimating one.

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