Fall Bloomers: A Sign of Zone Creep?

Photo courtesy of Walters Gardens — I wish my delphinium looked this good!

Maybe it’s the heavy rains we have had this fall or a sign of global warming, but I’m finding surprising things blooming. Yesterday, I discovered new blooms on an English Larkspur (Delphinium elatum ‘Pagan Purples’). I bought the larkspur late in the spring in hopes of getting taller flowers in the back of my front bed. According to the plant tag, this particular variety is supposed to grow 5 to 6 feet tall. (Other sources say 4 to 5 feet.) Unfortunately, right after I planted it, the weather turned very dry and I got very busy and neglectful of the garden. It died–or so I thought. Even though it had wilted right to the ground, a new plant emerged after I got around to watering the flowers more. It bloomed a couple of times in the summer, and now in mid-October. It never got tall–perhaps due to its difficult youth–but its still a lovely plant.

This morning, I noticed my catmint (Nepeta ‘Walker’s Low’) had several new blooms on it, too. Walker’s Low is known as a prolific bloomer, and I cut mine back after its first bloom in June to promote a second round of flowers. I expected them earlier or not at all.

It’s hard to know how to react to blooms in mid-October–part of me wants to rejoice. And, it’s certainly possible that the dry spell we had in July and August delayed blooms that would have appeared earlier had adequate rain fallen. Now it’s wet and not too cold so the plants bloom. Another part of me feels a little spooked by this much blooming so late.

Felicia Parsons, a horticulturist and writer, whose also a jeweler, wrote an excellent article on gardening with climate change in the July/August 2007 issue of Northern Gardener. She noted that the American Horticulture Society’s heat map (based on how many days over 86 degrees F an area has) shows a distinct zone creep over the USDA’s zone map, which is based largely on how cold things get. The Arbor Day Foundation has also released a zone map showing that Minnesota is getting warmer.

For gardeners, Felicia offers some advice: If you are deciding what to plant, plant what has always worked or try less hardy shrubs and perennials, but be prepared to take a loss if the weather gets back to “normal.” If you are concerned about global warming, do what you can to diminish your energy consumption (buy efficient appliances and better lightbulbs, drive less, plant a tree near the house to provide shade and reduce your need for air conditioning, compost) and watch what is happening in your own garden. Several web sites have been established for people to report changes they see in the plants and wildlife in their area, including this site from an organization in Wisconsin. This blog will be my report on what’s happening in my garden. Let me know what you see in yours.