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Predicting Cold-Hardiness in Palms
Larry R. Noblick, Ph.D.
Collections Manager, Montgomery Botanical Center &
Associate Researcher, Fairchild Tropical Garden, Miami, FL

In South Florida, we are fortunate to be blessed with a climate that is amenable to growing a wide variety of palms and cycads. However, the same is not true for other palm enthusiasts living in Central and North Florida, Texas, California, and elsewhere in the U.S. and in Canada. These growers struggle to keep their palms alive. This article is dedicated to the palm enthusiasts who willingly shared their experiences so that the rest of us do not continuously "repeat history". A compilation of observations made by Dent Smith (1958, 1962, 1986), Gordon Hintz (1978, 1996), Leonard Goldstein (1989), Paul Craft (1997), Kyle Campbell (1997), Eric Schmidt (1997), and others like Frederico Oste, Alan Ball (pers. comm.), Montgomery’s palm horticulturist, Laurie Danielson, and myself have resulted in Table 1, which lists all of these observations. From time to time I hope to update this Table at this website.

Some growers report different experiences with the same species of palm after a cold spell. The reasons for this involve the nature of the cold spell itself, microclimatic conditions that surround their palms, and the palms themselves. A cold spell can come on suddenly or slowly. One would think that a gradually cooling winter might give palms an opportunity to "harden off" or acclimate. But not so according to Goldstein (1989), who found that a sudden cold frost or freeze was far less devastating than an extended cold spell where temperatures never dropped to freezing. The length of time and depth of a hard freeze, wind speed, and ambient humidity can also influence how destructive a cold spell might be. That is why we see some reports of palms sustaining temperatures with little or no damage at one time, but dying at the very same temperature at another (Smith 1958, 1964). Microclimates and conditions that surround one’s personal collection can spell life of death for a palm. A plant sheltered by other trees and shrubs is more likely to fair better than one that is exposed. Finally, how successfully a palm will handle cold is determined by the palm itself: its age, its height, its slight hereditary differences selected out over time by the ambient conditions of its native habitat, and the overall health of the palm specimen itself at the time of the cold spell.

Predicting cold hardiness of palms would appear to be just a matter of answering a few questions. Does it grow in the cooler north or south latitudes? Is it a high altitude palm? However, there are some tropical species that have been found to be somewhat cold hardy. But, how can one predict what a tropical palm might do during a cold spell before gambling money and resources on it?

After examining information collected on palm hardiness (Table 1), I discoverered that over sixty-five percent of the species that showed no damage or very little damage at 25-26 F (-3.3 C) come from regions that have a distinct seasonal dry period. If a palm already has the cellular structure to handle the physical stress associated with dryness (specialized stomates, extra layers of wax to reduce transpiration, more rigid cell walls that do not collapse under conditions of low water pressure) , then it can presumably handle cold. Cold produces many of the same stresses that are brought on by a prolonged drought. During a cold spell, a palm’s ability to absorb or translocate water is severely reduced as its own cells function less efficiently at the lower temperatures. In addition, should a freeze actually occur, water in the form of ice crystals are no longer available for absorbtion or translocation. Thus cold causes a physiological drought.

Therefore, tropical or subtropical palms that are adapted to survive the stress of low water conditions (no matter what underlying conditions are causing it) will have a better chance of weathering a cold spell. Palms that grow in semi-arid areas, savannas, exposed sandy coastal zones, and on exposed well-drained rock faces are prime candidates for testing in colder climates, because they have the "right stuff".

LITERATURE CITED

CAMPBELL, K. 1997. The effects of the freeze of 1997 on palms in central and south Florida. Palm Review 17(2): 7-9.

CRAFT, P. 1997. Will Spring hurry up and get here?!!! The Broward County Palm and Cycad Society Newsletter.

GOLDSTEIN, L. 1989. Cold-weather experience in South Florida. Principes 33(2): 56-62.

HINTZ, G. 1978. Effects of the Winter of 1976-77 on certain palm species in Dallas, Texas. Principes 22(3): 94-98.

_________. 1996. Palms for South Texas gardens. Neil Sperry’s Gardens, January Issue.

PETERSON, B. 1997. Best place to learn about cold hardiness in palms. Palm Review 17(2): 1, 5.

SCHMIDT, E. 1997. Pleasant and not so pleasant surprises from Leu Gardens. The Broward County Palm and Cycad Society Newsletter.

SMITH, D. 1958. Cold tolerance of the cultivated palms based on observations made at Daytona Beach, Florida during the Winter of 1957-58. Principes 2(4): 116-126.

_________. 1964. More about cold tolerance: effects of a hard freeze upon cultivated palms during December, 1962, at Daytona Beach, Florida. Principes 8(1): 26-39.

_________. 1986. U.S.D.A. hardiness zones as applied to cultivated palms, and other horticultural comments. Principes 30(1). 26-31.


TABLE 1. Observations on cold hardiness in palms.

The symbols are as follows: a " O " means that the plant came through the cold spell undamaged--with "flying colors"; a " J " means that it was slightly damaged; a " K " means that it was moderately damaged; a " L " means that the plant was severely damaged, sometimes to the point of near death, but recovered; a " M " means that the plant obviously "bombed out" and did not survive; finally a " u " indicates what its cold hardiness limits are thought to be and in some cases these limits may have to be re-evaluated.

.

C

-8

-7

-6

-4.5

-3

-2

-1

0

1

Species

F

<=18

20

22

24

26

28

30

32

34

Acanthophoenix rubra

. . . .

.

M

. . . .

Aceolorraphe wrightii

18

u

.

O

.

O

. . . .

Acrocomia aculeata

. . . .

.

LJO

. . . .

Acrocomia totai

. . . .

.

O

. . . .

Actinorhytis calapparia

. . . .

.

u

. .

O

.

Aiphanes aculeata (= A. caryotifolia)

. . . .

.

ML

. .

J

.

Aiphanes lindendiana

. . . .

.

ML

. . . .

Aiphanes minima
  (= A. acanthophylla, A. erosa)

. . . .

.

Mu

. .

J

.

Allagoptera arenaria

. . . .

J

MO

O

. . .

Archontophoenix alexandrae

. . . .

.

ML

. .

J

.

Archontophoenix alexandrae var. beatricae

. . . .

MLK

K

. . . .

Archontophoenix cunninghamiana

. . . .

M

LK

. . . .

Archontophoenix purpurea

. . . .

.

u

. . .

J

Areca aliciae

. . . .

.

M

. .

J

O

Areca catechu

. . . .

.

M

. . .

L

Areca latiloba

. . . .

.

. . . .

O

Areca triandra

. . . .

.

L

. .

J

O

Areca vestiaria

. . . .

.

. . . .

O

Arenga caudata

. . . .

.

K

. . . .

Arenga engleri

. .

u

.

O

KJO

. . . .

Arenga pinnata

. . . .

L

ML

.

M

.

Arenga porphyrocarpa

. . . .

.

L

. . . .

Arenga tremula

. . . .

.

L

. .

L

.

Arenga undulatifolia

. . . .

.

. . .

K

.

Arenga wightii

. . . .

.

M

. . . .

Attalea humilis

. . . . . . . .

J

.

Astrocaryum mexicanum

. . . .

L

. . . . .

Bactris gasipaes

. . . .

.

L

. . .

J

Bactris major

. . . .

.

L

. . . .

Beccariophoenix madagascariensis

. . . .

.

J

. . . .

Bismarckia nobilis (intermediate)

. . . .

.

L

. .

K

.

Bismarckia noblilis (silver select)

. . . .

LK

LJO

. .

O

.

Borassus aethiopum

. . . .

J

O

. . . .

Brahea aculeata

. . . .

O

. . . . .

Brahea armata

0

O

. .

.

O

. . . .

Brahea brandegeei

. . .

u

.

O

. . . .

Brahea clara

. . . . .

O

O

. . .

Brahea dulcis

. . . . .

O

. . . .

Brahea edulis

. .

u

.

O

. . . . .

Brahea elegans

. . . . . .

J

. . .

Brahea nitida

. . . . .

O

O

. . .

Butia capitata

10

O

. .

O

O

. . . .

Butia eriospatha

. . . . .

O

. . . .

Butia paraguayensis

. . . . .

O

. . . .

Calamus caryotoides

. . . .  .

O

. . . .

Calamus hollrungii

. . . . . . . . .

O

Calamus usitatus

. . . . .

O

. . . .

Calyptrocalyx sp.

. . . . . . . . .

O

Carpenteria acuminata

. . . .

KL

u

. . . .

Caryota cumingii

. . . . .

M

. . . .

Caryota mitis

. . . .

L

ML

.

L

K

J

Caryota ochlandra

. . . . .

ML

O

. . .

Caryota urens

. . . . .

ML

O

.

O

.

Ceroxylon alpinum

. . . . .

O

. . . .

Ceroxylon quindiuense

. . . . .

O

. . . .

Ceroxylon vogelianum

. . . . . .

O

. . .

Chamaedorea brachypoda

. . . . .

LJ

.

O

. .

Chamaedorea cataractarum

. . . .

L

O

. . . .

Chamaedorea costaricana

. . . . .

L

. . . .

Chamaedorea elegans

. . . . .

MO

. . . .

Chamaedorea ernesti-augustii

. . . . .

M

. . . .

Chamaedorea fragrans

. . . . .

M

. . . .

Chamaedorea geonomiformis

. . . . .

M

. . . .

Chamaedorea glaucifolia

. . . . .

MJO

.

O

. .

Chamaedorea graminifolia

. . . . .

M

. . . .

Chamaedorea klotschiana

. . . . .

MO

. . . .

Chamaedorea liebmannii

. . . . .

M

. . . .

Chamaedorea metallica

. . . . .

O

. . . .

Chamaedorea microspadix

. .

J

.

O

O

. . . .

Chamaedorea oblongata

. . . . .

M

. . . .

Chamaedorea oreophila

. . . . .

M

. . . .

Chamaedorea pinnatifrons

. . . . .

M

. . . .

Chamaedorea plumosa

. . . . .

O

O

. . .

Chamaedora pumila

. . . . .

O

. . . .

Chamaedorea radicalis

. .

u

O

.

O

O

. . .

Chamaedorea schiedeana

. . . . .

M

. . . .

Chamaedorea seifrizii

. . . . .

LJ

. .

O

.

Chamaedorea stolonifera

. . . . .

JO

. .

O

.

Chamaedorea tenella

. . . . .

M

. . . .

Chamaedorea tepejilote

. . . . .

Mu

. .

J

.

Chamaerops humilis

0/9

uO

. .

O

O

. . . .

Chambeyronia macrocarpa

. . . . .

L

. .

O

.

Chuniophoenix hainanensis

. . . . .

O

O

. . .

Coccothrinax argentata

. . . . .

MLO

. .

J

.

Coccothrinax argentea

. . . . .

M

. . . .

Coccothrinax barbadensis

. . . .

J

MKO

. .

O

.

Coccothrinax crinita

. . . .

L

MLO

. . . .

Coccothrinax eggersiana

. . . . .

ML

. . . .

Coccothrinax fragrans

. . . . .

M

. . . .

Coccothrinax martii

. . . . .

ML

. . . .

Coccothrinax miraguama

. . . . .

MLJ

. .

O

.

Coccothrinax yuraguana

. . . . .

M

. . . .

Cocos nucifera

. . . . .

MLJ

. .

J

J

Cocos nucifera "Green Maypan"

. . . . .

K

. .

J

.

Copernicia alba

. . . .

K

ML

. .

O

.

Copernica baileyana

. . . .

K

K

. .

O

.

Copernicia berteroana

. . . . .

ML

. .

J

.

Copernicia curtissii

. . . . .

K

. . . .

Copernicia ekmanii

. . . . .

L

. . . .

Copernicia fallaense

. . . . .

J

. .

O

.

Copernicia glabrescens

. . . . .

LO

. . . .

Copernicia gigas

. . . . .

L

. . . .

Copernicia hospita

. . . . .

J

. .

O

.

Copernicia macroglossa

. . . .

J

MJ

. . . .

Copernicia prunifera

. . . . .

MO

. . . .

Corypha umbraculifera

. . . .

L

MJ

. . . .

Corypha utan

. . . . .

M

. . . .

Cryosophila guargara

. . . . . . . . .

J

Cryosophila stauracantha

. . . . .

J

. . . .

Cryosophila warscewiczii

. . . . .

ML

. .

O

.

Cyphophoenix nucele

. . . . .

J

. . . .

Daemonorops angustifolia

. . . . .

K

. .

O

.

Dictyosperma album

. . . .

ML

M

. .

J

J

Drymophloeus beguinii

. . . . .

MuJ

. .

J

.

Dypsis cabadae

. . . .

L

L

. .

J

.

Dypsis decaryi

. . . .

L

M

. .

O

.

Dypsis decipiens

. . . . .

J

. . . .

Dypsis lanceolata

. . . . . . . . .

J

Dypsis lastelliana

. . . . . . . . .

J

Dypsis leptocheilos

. . . . . . . . .

J

Dypsis lutescens

. . . .

L

LJ

. .

O

.

Dypsis madagascariensis

. . . .

M

LK

. .

J

.

Dypsis pinnatifrons

. . . . .

u

. .

O

.

Elaeis guineensis

. . . . . MLJ . . .

J

Euterpe edulis

. . . . .

M

. . .

J

Euterpe precatoria

. . . . . .. . . .

O

Gastrococos crispa

. . . . .

J

. . . .

Gaussia attenuata

. . . . .

M

. . . .

Gaussia maya

. . . . .

ML

. .

K

J

Guihaia argyrata

16

L

. . .

O

O . . .

Gulubia microspadix

. . . . . . .. ..

J

.

Hedyscepe canterburyana

. . . . .

M

. . . .

Heterospathe elata

. . . . .

ML

. . . .

Howea belmoreana

. . . . .

M

. . . .

Howea fosteriana

. . . .

K

MLK

. .

O

.

Hyophorbe indica

. . . . .

M

. .

J

.

Hyophorbe lagenicaulis

. . . .

L

L

. .   .

K

Hyophorbe verschaffeltii

. . . . .

ML

  . .

O

J

Iguanura wallichiana

. . . . . . . . .

J

Iriartea gigantea

. . . . . . . . .

J

Johannesteijsmannia altifrons

. . . . . . . . .

O

Johannesteijsmannia magnifica

. . . . . . . . .

O

Jubaea chilensis

-4

L

. . .

O

. . . .

Kerriodoxa elegans

. . . . .

K

. . . .

Laccospadix australasica

. . . . .

O

. . . .

Latania loddigesii

. . . ..

L

u

.. ..

J

..

Latania lontaroides

. . . ..

L

u

. .

L

.

Latania verschaffeltii

. . . . .

M

. .

J

.

Lepidorrachis mooreana

.. .. .. .. ..

O

. . . .

Licuala elegans

. . . . .

J

. . . ..

Licuala grandis

. . . ..

J

MLJ

. .

J

.

Licuala peltata

. . . . .

MJ

. .

O

.

Licuala ramsayi

. . . . .

J

. .

O

.

Licuala spinosa

. . . ..

LK

KJ

. .

O

.

Linospadix monostachya

. . . . .

O

. . . ..

Livistona australis

. . . ..

JO

O

. . . ..

Livistona benthamii

. . . . .

JO

. . . ..

Livistona chinensis

. . . ..

LO

O

. . . ..

Livistona decipiens

. . . ..

O

O

. . . ..

Livistona drudei

. . . ..

O

JO

. .

O

.

Livistona fulva

. . . . .

K

.. .. . ..

Livistona jenkinsiana

. . . . .

J

.. .. . ..

Livistona mariae

. . . . .

JO

.. .. . ..

Livistona muelleri

. . . ...

J

MJ

.. ..

O

..

Livistona rigida

. . . . .

JO

.. ..

J

.

Livistona robinsoniana

. . . . . . ..

O

J

.  .

Livistona rotundifolia

. . . ..

L

L

.

J

.. ..

Livistona saribus

. . . ..

J

O

J

..

J

.

Lodoicea maldivica

. . . . . . . .

J

.

Lytocaryum weddellianum

. . . . .

MJO

. . . ..

Marojejya darianii

. . . . .

M

..

J

O

..

Mauritia flexuosa

. . . . .

M

.. .. . ..

Nannorrhops ritchiana

-4/10

u

.. . .

O

.. .. . ..

Nenga pumila

. . . . . . . .. ..

O

Nephrosperma vanhoutteanum

.. . . . .

M

.. .. . ..

Normanbya normanbyi

.. . . . .

O

.. .. . ..

Orbignya cohune

.. . . . .

O

.. .. . ..

Orbignya phalerata

.. . . . .

JO

.. .. . ..

Orianiopsis appendiculata

.. . . . .

M

.. .. . ..

Parajubaea cocoides

.. . . . .

O

O

. . .

Phoenix acaulis

.. . . . .

J

. .

O

.

Phoenix canariensis

10

ML

u

. .

O

.. .. . ..

Phoenix dactylifera

. .

J

. .

O

.. .. . ..

Phoenix hanceana

.. . . . .

O

.. .. . ..

Phoenix loureirii

.. . . . .

O

.. .. . ..

Phoenix paludosa

.. . . . .

L

. .

J

.

Phoenix pusilla

.. . . . .

KJ

. .

O

.

Phoenix reclinata

  . .

K

  .   .

JO

. .

O

.

Phoenix roebelenii

. . .

J

K

JO

O

.

O

.

Phoenix rupicola

. . . . .

JO

. .

O

.

Phoenix sylvestris

-4

K

. .

J

JO

.. .. . ..

Phoenix theophrasti

. .

J

. .

O

.. .. . ..

Physokentia dennisii

. . . . . .. .. . ..

J

Physokentia insolida

. . . . . .. .. . ..

J

Phytelephas macrocarpa

. . . . .

M

.. .. . ..

Pinanga coronata (=P. kuhlii)

. . . . .

ML

. .

J

.

Polyandrococos caudescens

. . . . .

K

. .

O

.

Prestoea acumintata (= P. montana)

. . . . .

M

. .

O

.

Pritchardia beccariana

.. .. . ..

L

K

.   .

O

.

Pritchardia pacifica

. . . . .

M

.. .. . ..

Pritchardia thurstonii

. . . . . ML .. .. . ..

Pritchardia hildebrandii

. . . . .

K

. .

O

.

Pritchardia vuystekiana

. . . . . .. . ..

K

.

Pseudophoenix sargentii

. . . .

L

JO

. . . .

Pseudophoenix sargentii ssp. saonae

. . . . .

M

. . . .

Pseudophoenix vinifera

. . . . .

M

. . . .

Ptychosperma elegans

. . . . .

Mu

. .

O

.

Ptychosperma macarthuri

. . . . .

M

. . . .

Ptychosperma microcarpum

. . . .

L

. . . . .

Raphia farinifera

. . . . .

L

. . . .

Raphia taedigera

. . . . .

M

. .

K

.

Ravenea madagascariensis

. . . . .

K

. .

O

.

Ravenea rivularis

. . . . .

J

. .

O

.

Ravenea sambiranensis

. . . . .

K

. .

O

.

Ravenea xerophila

. . . . .

O

. . . .

Reinhardtia gracilis

. . . . .

M

. .

O

.

Reinhardtia latisecta

. . . . . . .. .

O

.

Reinhardtia simplex

. . . . . . .. .

O

.

Rhapidophyllum hystrix

-5

u

O

.

O

O

. . . .

Rhapis excelsa

. . . .

O

O

. . . .

Rhapis humilis

. . . . .

O

. . . .

Rhapis multifida

. . . . .

O

. . . .

Rhapis subtilis

. . . . .

O

. . . .

Rhopalostylis baueri

. . . . .

ML

. . . .

Rhopalostylis sapida

. . . . .

JO

. . . .

Roystonea oleracea

. . . . .

M

. . . .

Roystonea regia

. . . . .

MLK

. .

O

.

Sabal bermudana

. . . . .

O

O

. . .

Sabal causiarum

. .

u

. .

O

. . . .

Sabal domingensis

. . . . .

O

. . . .

Sabal etonia

5

u

. . .

O

. . . .

Sabal guatemalensis

. . . . . .

O

. . .

Sabal maritima

. . . . .

JO

. . . .

Sabal mauritiiformis

. . . .

J

JO

. .

O

.

Sabal mexicana

10

u

. .

O

O

. . . .

Sabal minor

5

u

O

.. .

O

. . . .

Sabal palmetto

10

u

O

. .

O

. . . .

Sabal parviflora

. . . . .

O

J

. . .

Sabal rosei

. . . . .

O

. . . .

Sabal uresana

. .

u

.

O

O

. . . .

Sabal yapa

. . . . .

MJO

. .

O

.

Salacca zalacca

. . . . .

M

. . .

O

Satakentia liukiuensis

. . . . .

u

. .

J

.

Scheelea butryracea

. . . . .

J

. . . .

Scheelea liebmanii

. . . . .

J

. .

O

.

Scheelea robusta

. . . . .. . . . ..

J

Scheelea rostrata

. . . . .

L

. .

O

.

Schippia concolor

. . . . .

J

. .

O

.

Serenoa repens

15

u

. . .

O

. . . .

Syagrus amara

. . . . .

LJ

. .

J

.

Syagrus botryophora

. . . . . . . . .

K

Syagrus coronata

. . . . .

LKJ

. .

J

.

Syagrus x costae

. . . . .

K

. . . .

Syagrus oleracea

. . . . .

K

. .

O

.

Syagrus picrophylla

. . . . .

L

. .

O

.

Syagrus pseudococos

. . . . .

L

. .

J

.

Syagrus romanzoffiana

. . . .

LKJ

LO

. . . .

Syagrus sancona

. . . . .

L

. . . .

Syagrus schizophylla

. . . .

L

ML

. . . .

Syagrus stenopetala

. . . . . . . . .

J

Synechanthus fibrosus

. . . . .

MJ

. .

O

O

Thrinax morrisii

. . . . .

JO

. .

O

.

Thrinax parviflora

. . . . .

MJ

. .

O

.

Thrinax radiata

. . . . .

KJ

. .

O

.

Trachycarpus fortunei

0

J

. . .

O

. . . .

Trachycarpus martianus

. .

J

. .

O

. . . .

Trachycarpus takil

. . . . .

O

. . . .

Trachycarpus wagnerianus

10

u

O

. .

O

. . . .

Trithrinax acanthocoma

5

u

O

. .

O

. . . .

Trithrinax brasiliensis

. . . . .

O

. . . .

Trithrinax campestris

. .

O

.

O

O

. . . .

Veitchia merrillii

. . . . .

M

. .

K

.

Veitchia montgomeryana

. . . .

L

M

. .

J

J

Wallichia disticha

. . . .

J

L

.. .

J

.

Washingtonia filifera

0

O

. . .

O

. . . .

Washingtonia robusta

. .

J

. .

O

. . . .

Wodyetia bifurcata

. . . . .

LJ

. .

O

.

Zombia antillarum

. . . .

LJ

LJO

. .

O

.

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