Zoned Out

Garlic recovered from its weather-beaten start and grows strong and healthy.

Somehow the mild winter and abnormally early spring of 2012, while extremely pleasant, caused a severe case of writer’s block.  Perhaps welcoming the end of the world with a lovely brunch on the deck in March (to paraphrase Peter Segal) created too much cognitive dissonance for my feeble faculties.

Now with the great unfurling of green throughout the northern hemisphere nearly complete (a good 2 weeks earlier than normal here –whatever normal is anymore) the super power of all that surging chlorophyll finally broke through the funk.  I resolve to write and post on a regular basis once again.

In January, the USDA issued a new plant hardiness zone map.  Considered more accurate than the previous version issued in 1990, it incorporates data from the last two decades.  Thanks to the availability of this higher level of detail, it now features a way to search for your zone by zip code.

Imagine my relief when our property landed in Zone 4.  No need to change the name of this blog yet!

But with the record-breaking warmth experienced lately, could the new map be out of date already? The new zone map suggests we have shifted from the slightly colder Zone 4a (average low temperatures of minus 30-35 degrees F) to Zone 4b (minus 30-25 degrees F).  It’s hard to pinpoint our location on the 1990 zone hardiness map as it is too coarse with no zip code feature for more precise ID, but based on my gardening records when we moved here in 1990,the winter conditions at that time were better described as Zone 4b.

From the lack of prolonged periods of sub-zero temperatures during the last several winters and increasing rarity of even brief dips into the double digits below zero, I suspect our local climate has already shifted decisively into Zone 5.  Plants reportedly unsuited to Zone 4, like crocosmia and culinary thyme, now overwinter without protection.  Lavender planted in the early 90′s next to a south-facing stone wall, sulked for more than a decade but now flourishes as do the new plants, placed in more exposed locations.

Cold hardiness has implications beyond surviving average cold temperatures, as we learned from the ups and downs of this past, unseasonably warm winter. Day lily shoots, those tough little spikes of pale green that announce the start of spring, emerged during the uncanny week of summer temperatures in mid March, growing fast and leggy.  Bitterly cold temperatures then followed with a whoosh of freezing winds.  Those normally hardy plants that push up as soon as the ground thaws were caught unprepared and their fleshy growth unaccustomed to freezing, withered in the icy blast.  Besides the day lilies, the deep cold damaged the just-emerging garlic leaves and decimated the celery-flavored lovage shoots that normally season our delicious duck eggs for brunches on chilly spring weekends.

All have now recovered and flourish,  no permanent damage done.  We can only hope to do as well as we navigate the uncharted climate zones ahead.