Weather plays such a fundamentally determinant role in designing a satisfying garden. For us New Englanders, the long-awaited start of spring is always such a welcome time. Those fragrant, warm breezes and first bright flowers encourage us to spend more hours outdoors, taking in the beauty of the season. But last winter brought us such unusual weather that the performance of some of our favorite spring bloomers has been affected in abnormal ways that only Mother Nature controls.
According to the National Oceanic and Atmospheric Administration, Boston-area temperatures averaged 37.5 degrees Fahrenheit from December 2015 through February, giving us the second-warmest winter since recordkeeping began in 1870. For those of us who enjoy our yards, this statistic might indicate that once again spring will be spectacular; all those less-winter-hardy trees and shrubs we’ve planted that have performed so well in our gardens over the past couple of decades will escape winter damage. But relying upon only average temperatures can be deceptive. They don’t realistically recognize the effect of the extremes.
On Feb. 14, the temperature in Boston fell to minus 9, the lowest recorded since Jan. 15, 1957. In Worcester, it was minus 16, the lowest since Jan. 15, 1957. And then from April 3-6, following a significantly warmer-than-normal March, Boston reported lows in the 20s, while Worcester had a range of low temperatures from the 20s to the teens, a major setback for some flowering plants just unfurling their blooms. These nefarious, double-impact temperature extremes damaged many of our favorite early-flowering plants, including magnolias, forsythia, and even some of the hardiest rhododendrons like “PJM.’’ And as our evergreen azaleas and large-leaf rhododendrons try to open their blooms in the next few weeks, we can be certain that some of their buds will prove to have been “blasted.’’ The result will be a less spectacular display than usual or no flowers at all on some less hardy plants this spring.
So how can we design gardens that factor in temperature anomalies like this? For many homeowners, these temperature glitches are more of an annoyance than a big problem. When winter temperatures moderate over a long period, plants deacclimate. They release their winter dormancy cold tolerance, “assuming’’ it’s time to start growing. Fortunately, even when their flowers and new-growth shoots are damaged by unexpected freezing, most landscape plants are resilient and fully recover over the springtime, albeit sacrificing until next year their usual floral display.
Designing plantings using hardy cultivars helps reduce temperature-caused disappointments like these. With some exceptions, Zone 5 plants will perform as expected this year. Choosing a diversity of plants that come into bloom at different times during the year helps spread the risk and enhances your enjoyment over a broader season. Interspersing a broad variety of evergreens, trees, shrubs, and herbaceous plants always adds interest and value.
Perhaps most important for your yard design, remember that the majority of woody and herbaceous plants typically bloom for only a week or two each year. The appearance of form, foliage, fruit, branching, and new growth over the remaining time is the key factor homeowners often fail to consider when they make their garden design choices. The professionals at your local garden center are knowledgeable about how winter has affected local plantings. They also are well equipped to advise on choosing the right plants to optimize the year-round enjoyment of your yard.
Wayne Mezitt is a third-generation nurseryman, a Massachusetts certified horticulturist, chairman of Weston Nurseries of Hopkinton and Chelmsford, trustee chairman for the Massachusetts Horticultural Society at Elm Bank, and owner of Hort-Sense, an advisory business. Send comments to Address@globe.com.
