The Freeze of 2007: Responses in a San Diego County Garden

In the July 2008 issue of Pacific Horticulture, garden writer and horticultural consultant Nan Sterman wrote about 2007’s extreme weather in Southern California, noting the significant consequences visible in her garden in Northern San Diego County. Only three miles from the Pacific Ocean, her garden sits at the bottom of a coastal valley that typically sees light frosts each winter.

In January 2007, however, a massive cold front descended upon the region, dropping temperatures in her garden to an estimated 15° to 19° F, depending upon the location within her sloping garden; nighttime temperatures were only a few degrees warmer over then next several days. Although plants, at first, seemed to have survived the cold snap, damage began to show up after about two weeks. Some plants responded with new growth almost immediately, but most waited until spring or summer to show genuine signs of recovery; some took nearly a year to recover.

Here is Nan’s summary of some of the major plants in her garden and their responses to the freeze.

Plants that Died
Aeonium cvs.
variegated and dark-leafed aeonium selections
•plants appeared to have melted!

Agave guiengola
•plants in a cooler part of the garden showed damage after the first week; mother plant died, leaving behind pups she had protected through the freeze

Aloe thraskii
coast aloe

Archontophoenix purpurea
purple crown-shaft king palms
•nine-foot-tall plants

Athanasia trifurcata

Brugmansias versicolor, B. hybrids
angel’s trumpets (tropical origins)
•planted in the ground without protection

Calothamnus quadrifidus
•struggled for about nine months, then died

Citrus aurantiifolia ‘Mexican’
Mexican lime tree
•planted in containers

Dracaena draco
dragon tree
•lost all leaves initially, but the four-foot-tall stump remained green for a year before I acknowledged its death

Duranta erecta
skyflower
•planted in the ground

Ficus aspera
clown fig

Melaleuca diosmifolia
•ten feet tall

Passiflora edulis ‘Fredrick’
passion vine
•usually one of the hardier selections

Pimenta dioica
allspice
•young plant, only four feet tall

Senna bicapsularis ‘Buttercreme’
winter cassia
•ten-foot-tall plant

Sida fallax
ilima
•fifteen-foot-tall tree, started from a cutting; died back to the base slowly, from the outermost branches inward; tried to re-sprout from the base by summer, but to no avail

Thevetia peruviana
yellow oleander
•died back to the base, started sprouting after a year, then I accepted its death

Plants that Recovered within Six Months
Aeonium cvs.
green-leafed aeoniums
•leaves were damaged, but plants recovered

Alstroemeria cvs.
Peruvian lily
•new sprouts appeared within a few weeks

Citrus aurantiifolia ‘Mexican’
Mexican lime tree
•planted in the ground, they were severely damaged and not expected to survive, but they recovered

Citrus limon
Eureka lemon
•some branch dieback, but all recovered within six months

Citrus x paradisi ‘Oro Blanco’
grapefruit
•outer leaves turned brown, but the plant quickly recovered

Cuphea llavea
bat-faced cuphea
•died to the ground, but re-sprouted in spring

Cymbopogon citratus
lemon grass
•leaves were browned, but plant quickly recovered

Ferns (various species, including tree ferns)
•damaged fronds, but plants recovered

Fortunella
Kumquat
•half of the fruits turned to mush, but the rest hung on for an entire year (and were the best tasting fruits ever!)

Globularia x indubia
globe daisy

Heliconia spp., Alpinia zerumbet ‘Variegata’, and others
tropical gingers

Salvia ‘Waverly’
Waverly sage

Salvia africana lutea
South African dune sage
•outer parts were damaged, but new sprouts appeared from the roots within a year

Salvia karwinskii
Karwinski sage
•plants recovered in a few months

Salvia lanceolata
Rocky mountain sage
•planted in the (colder) back garden; recovered in a few months

Salvia mexicana
Mexican sage

Plants that Recovered by One Year
Agave attenuata
foxtail agave
•plants showed damage after the first week, but eventually fully recovered

Brachychiton rupestris
bottle tree
•leaves showed damage after two weeks; trees were completely recovered and had added several feet of height within a year

Caesalpinia spp.
bird of paradise bushes
•two-foot-tall plant

Caesalpinia cacalaco
cascalote

Crotalaria agatiflora
canary bird bush
•plant nearest the house (most protected) recovered in a few months

Polygala x dalmaisiana
sweet pea bush
•outermost branches died back, making for a misshapen plant

Saccharum officinarum var. violaceum
purple-leaf sugar cane
•canes died back to the roots but re-sprouted by summer

Thevetia peruviana
yellow oleander
•sheltered under a pepper tree; some pruning required to remove dead branches

Plants that Took Longer than One Year to Fully Recover
Agave guiengola
•one plant in a warmer part of the garden showed damage after the first week, but recovered within a year

Aloe rubroviolacea and A. marlothii
•plants showed damage after the first week, but recovered within a year

Bromeliads (various species and hybrids)
•all were in pots; severe damage showed up after several months, but plants recovered

Brugmansia sanguinea ‘Inca Queen’
red angel’s trumpet (Andean origin)
•re-sprouted in summer

Crotalaria agatiflora
canary bird bush
•plant in a low (colder) area of the garden took nearly a year to reappear

Syzygium paniculatum
eugenia
•plants in a tall hedge were severely damage; all were pruned back heavily and recovered

Michelia champaca ‘Alba’
fragrant Himalayan champaca
•eight-foot-tall tree in a pot under the front porch overhang; branches that extended beyond the covering were burned, whereas protected branches were fine; leaves dropped, but branches re-sprouted by summer

Psidium guajava
Tropical guava
•eight-foot-tall, established tree died back nearly to the base, but re-sprouted