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Kathy’s Garden Writing |
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GARDENING WITH CLIMATE CHANGE Do you know where your garden is -- zone-wise, that is? Thanks to global warming, as of 2006, most of Northeast PA has been reclassified from Zone 5 to a milder Zone 6 by the National Arbor Day Foundation (check out arborday.org/treeinfo/zonelookup.cfm). What does it mean to have a Zone 6 garden? Well, on average (and as gardeners everywhere know, averages are reliably unreliable for particular sites), winter temperature lows range from -10 degrees to 0 degrees. And last frost dates occur sometime in April. Probably none of you can recall a winter temperature below -10 degrees since the start of the new millennia. And how about the way we’re all pushing the planting season, putting out tomatoes and other tender annuals often before Mother’s Day? Maybe those Arbor Day folks are on to something! The good news is that new plants will survive in our gardens, courtesy of warming trends. The bad news is that some of our favorites may no longer thrive in our altered growing conditions. So let’s look at the upside. In years gone by, many plants grown by our Philadelphia acquaintances did not reliably overwinter here in Northeast PA. Buddleia, caryopteris, and vitex come to mind, all lovely purple-hued shrubby perennials. You may now want to give them a try. And have you envied the Italians their year-round rosemary plants? It may be a safe bet to add one of the hardier varieties to your perennial herb bed, particularly if you provide some winter shelter. Sandy Mush Herb Nursery (sandymushherbs.com) offers 25 different rosemary selections, two of which, ‘Arp’ and ‘Salem,’ are advertised to grow in Zone 6 with some protection. So treat your plant envy with an online herb purchase! Of course there are many vegetables that will thrive with a longer, hotter growing season. Sweet potatoes, heirloom melon varieties, pole lima beans, and even Southern okra may become staples in our new climate-altered vegetable patches. Perhaps in a particularly warm year, artichokes may even survive the winter as perennials (try covering with a bushel basket and loose mulch). But sadly climate change also brings a downside for our landscapes. The Arbor Day folks tell us that we may lose our beautiful state flower, the mountain laurel, except at the highest elevations. And those of us who have been fighting the wooly aphids that infect hemlocks already know that the state tree is in trouble. Who knows what other species may be challenged? Delphiniums have certainly struggled recently. And other stalwarts of Northeast cottage gardens, like hollyhocks, lily-of-the-valley, baby’s breath, lupines, and primroses, may succumb except in the most ideal circumstances. So we can drive more energy efficient cars and switch to fluorescent lighting, and turn our thermostats down in the winter and up in the summer. But in our gardens, it may be best to “make lemonade out of lemons” and work with Mother Nature. Hmm, lemon trees, now that’s an interesting thought – maybe next decade! Sidebar: Gardeners can make a difference in the battle with global warming: 1. Keep invasive plant and pest species in check, as these will threaten weakened ecosystems. 2. Conserve water by mulching, installing rain barrels, using drought tolerant plants; and don’t water in mid-day. 3. Compost, compost, compost, and avoid chemical fertilizers; in fact, avoid chemicals of all kinds. 4. Plant trees around the house for summer cooling and winter wind protection, and to absorb carbon dioxide. 5. Avoid the use of gasoline-powered yard tools. Kathleen Arcuri Published March 9, 2008 – The Danville Daily Item |