Regional Gardening Reports :: National Gardening Association

In the Garden:
New England
April, 2002
Regional Report

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Plant corn when oak leaves are the size of a squirrel's ear. Note that I took this photo last year -- it's not time to plant corn yet!

Phenology, the

With the recent warm temperatures, spring has definitely "sprung" here in the Northeast. My husband and I just got back from two weeks in Florida, and were thrilled to find blooming daffodils and sprouting perennials in our yard.

Two weeks earlier we had left gray, late-winter Vermont, and during our 1500-mile, 26-hour drive southbound we enjoyed watching the progress of the growing season. We passed through all stages of spring, from budding maples in New Jersey, to blooming fruit trees and dogwoods in Virginia, to azaleas in full flower in the Carolinas, and finally, to lush, green Florida. In one day we progress through the equivalent of the two months of spring!

Climate and Plant Growth
Perhaps more than most people, gardeners appreciate the relationship between climate and life cycles. As we observe the cycles of growth in our gardens, especially among trees, shrubs, and perennials, we become familiar with seasonal patterns. The study of this relationship between climate and biological phenomena is called phenology. The word translates to "the science of appearances," evoking images of the return of the first robins of spring, the emergence of new perennial shoots, and the exuberant flowering of fruit trees -? "appearances" we gardeners joyfully anticipate each year.

Aldo Leopold, an internationally respected scientist and conservationist, was an avid phenologist. He kept extensive records of natural seasonal events near his home in Sauk County, Wisconsin. He wrote, "Many of the events of the annual cycle recur year after year in a regular order. A year-to-year record of this order is a record of the rates at which solar energy flows to and through living things. They are the arteries of the land. By tracing their responses to the sun, phenology may eventually shed some light on that ultimate enigma, the land's inner workings."*

Phenology in the Garden
Phenology isn't just an intellectual endeavor, however. It can be a useful tool in deciding when to plant specific crops and when to expect insects and diseases to make their appearances. Perhaps the most famous phenology phrase is, " Plant corn when oak leaves are the size of a squirrel's ear." Although the two plants are unrelated, Native Americans observed centuries ago that when the oak leaves were this size, the soil was warm enough to prevent corn seed from rotting, but it was still early enough for corn plants to fully mature before cold weather set in. The history of phenology goes back even further -- the first known treatise was written in 974 B.C.!

More Lore
Here are some other old sayings:

--Plant potatoes when the shadbush flowers.

--Plant peas when daffodils begin to bloom.

--When peach and plum trees are in full bloom, plant hardy vegetable crops.

--When you see new growth on green ash, grapes and bur oaks it is safe to plant tender vines, annuals and perennials.

--When elm leaves are the size of a penny plant kidney beans.

--When the blossoms of the apple tree begin to fall, plant your corn seeds.

--When the common lilac plant has leafed out plant lettuce, peas and other cool weather varieties. When its flowers are in full bloom plant beans and squash.

--When the flowering dogwood is in peak bloom it is time to plant tomatoes, early corn and peppers.

--Plant tomatoes and peppers when daylilies start to bloom.

--Direct seed your morning glories when maple trees have full-size leaves.

Climate and Geography
Scientist have determined that phenological "events" are delayed by four days per degree of north latitude and 1 and 1/4 days per degree of east longitude. The farther north or east you go, the later you'll see similar events. This doesn't take into account altitude, proximity to bodies of water, or other variables, however.

Consider keeping your own phenology records, and comparing them with the folklore and with gardening friends in other parts of the country. The wonders of nature and the joys of gardening are limitless!

*Aldo Leopold, A Phenological Record for Sauk and Dane Counties, Wisconsin, 1935-1945 (1947)

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