Local gardens suffered severe freeze damage

By Bill Klausing, Sonoma County Master Gardener

Dryopteris (wood fern)

With only a few days of advance warning, early December 2013 brought some of the coldest temperatures seen in Sonoma County for the past half century. Though the official lowest temperature in Santa Rosa was posted as 20 degrees, my patio thermometer dropped into the teens on 5 consecutive nights, with a low of 16 degrees on December 9.   Needless to say, the damage in my own little corner of the county was extensive. One of the more devastating aspects of this particular cold snap is that it minimized many of the normal warmer microclimates that local gardeners have become used to. Plants and shrubs located in the warmer and more protected areas of the garden were provided little comfort. Sub-freezing temperatures were experienced in every corner of the county, including coastal areas normally immune to freezes. The exceedingly dry weather this winter only exacerbated some of the frost damage to plants.

Each successive frigid morning when I arrived at work, there were many questions from co-workers: “What should I do?”; “can I cut back all that ugly dead stuff?”; “Will my hydrangeas survive?”.   And the answers are fairly uniform to all questions.   Do nothing. Be patient. Put away all shears until springtime (March or April). Many shrubs, even if severely damaged, will ultimately survive. The frost damaged areas of these specimens will still provide some protection for each plant.   Any removal will only make plants increasingly susceptible to further damage, particularly if another penetrating cold snap occurs later this winter.

If a plant needs to be sacrificed, you really won’t know for sure until perhaps early summer when it becomes more than apparent that a plant’s vigor is gone. If you are like me (and most gardeners that I know), we like to push the boundaries on specimens that are a little less cold hardy than the climate we live in.   Those Aeonium and other tender succulents in containers on the patio that normally survive with a little extra protection–might not have this time. CoprosmaPelargoniumEschium,TibouchinaLantana? Only time will tell. Even the ubiquitousDietes grandiflora, which have probably been on my property since 1962–all frozen to the quick.

Citrus damage is of particular concern to many Sonoma residents. Meyer Lemon and Satsuma survived on my patio without cover. A much more tender Tangelo Minneola, which was covered, has moderate damage but should be fine in the long run. UCANR has agreat publication for gardeners who would like more detailed information on dealing with cold weather, citrus, and subtropicals. May the force be with your plantings.

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