AVERAGE Annval 
LOWEST Temperature for Each Zone 
ZONE 1+ N. & Cent. Canada ZONE 6 - —5toj 5 
ZONE 2 - —5S0to—35 , ZONE 7+ } Sto 410 
ZONE 3 - —35 to —20 ZONE 8 + +10 to +20 
ZONE 4 » —20 to —10 ZONE 9 + +20 to +30 
ZONE 5 - —10to— 5 ZONE 10 - 430 to +40 
ZONES are an APPROXIMATE basis for choosing 
the kinds of plants which can survive AVERAGE 
winters. People who use EXTRA CARE, who pro- 
tect plants with mulches, wind screens, etc., may 
succeed with a plant in places one or even two 
zones colder than is NORMAL for that plant. Peo- 
ple who give NO special care may lose a plant, 
even in a normal zone, when the first ‘‘hard win- 
ter’’ arrives. 
t 
$Y) 
COPYRIGHT—1951 
by W. Warren Anderson 
REMEMBER—ALL PLANTS when young, are more 
tender to freezing by two or three zones. The “‘in- 
fancy period’’ of all plants varies from a few 
weeks for annuals to 10 or even 20 years for a 
tree that lives several thousand years. 
The LOWEST winter temperatures each year for 
40 years—recorded by the U.S. Weather Bureau— 
were averaged to outline these zones. This study 
covered 1895 to 1935. 
CLIMATIC ZONES FOR REDWOOD TREES 
LOWEST Winter Temperatures (Fahr.) For Each 
This is the ONLY study of WINTER HARDINESS of the 15 living species of ‘’Redwood Trees” 
ever made—and will probably be improved—although we believe it to be substantially accu- 
rate. It was compiled from data on these trees growing in the United States and in many foreign 
lands. NO ONE can guarantee the success of ANY plant, in ANY environment. 
CLIMATE = ZONE Peers Species of ‘Redwood’? Suitable 
ARCTIC i — ?to—50 Probably NO Redwood can succeed. 
eZ —50 to —35 ZONE 3 trees MIGHT survive with exceptional site 
and care. 
COLD 3 —35 to —20 Metasequoia, Taxodium distichum, Taxodium ascen- 
dens—all deciduous. 
4 —20 to —10 Above trees have proved hardy. 
Cold 5 —10to— 5 Trees in above zones—also Sequoia gigantea, Cryp- 
TEMPERATE tomeria (Species), Sciadopitys. 
6 — Sto+ 5 Trees in ALL zones above. 
7 + Sto +10 Trees in ALL zones above. 
Warm 8 +10 to +20 Trees in ALL zones above—also Sequoia sempervi- 
TEMPERATE rens, Cunninghamia sinensis, Athrotaxis cupres- 
soides. 
' Trees in ALL zones above—also Taxodium mucrona- 
tum, Taiwania, Cunninghamia Konishii, Athrotaxis 
selaginoides. Athrotaxis laxifolia, Glyptostrobus. 
9 +20 to +30 
SUB-TROPICAL 10 
TROPICAL 
+30 to +40 
HEAT—not cold 
is the problem 
Trees in ALL zones above. 
In shaded, deep-forest—trees in ALL zones above. 
SOLITARY trees, NOT shaded—ONLY Taxodium 
mucronatum, Taiwania, Cunninghamia Konishii, 
Glyptostrobus. 
FOREIGN LANDS: Consult your own records of LOWEST WINTER TEMPERATURES, to de- 
termine which Zone applies to YOUR location. We will greatly appreciate your sending us 
such LOWEST temperature records, from anywhere in the world. 
NOTE: For data on planting site, time and method—and CARE of Redwood Trees, see our 
booklet “You Too Can Grow A Redwood Tree.” 
HORTUS II lists 14 “Redwoods"—Harvard University proved “graft-compatibility” 
