In early October, I hiked to a summit that provided a lovely vista of Squam Lake and the surrounding hillsides. In a typical year, the view would have provided a spectacular array of colors from New Hampshire’s famous fall foliage. Not this year.
The seasonal color change of deciduous leaves is influenced by many variables. A key factor that determines leaf color is the type of plant. Pigments in fall leaves vary by species. Red maples display a glorious crimson hue and are often among the first to turn, especially in swampy areas. Sugar maples add a rich orange to the palette. Birches, beeches and aspens glow yellow in the fall sunlight. Oaks bring up the rear of the parade of colors, waiting until late October to trade their green chlorophyll for russet red or bronzy orange, depending on the species. The wide range of colors produced by the diversity of tree and shrub species in New England forests is one of the things that makes our region a prime fall destination for tourists from far and wide.
Whether or not the “leaf-peepers” experience vibrant colors is impacted by precipitation and temperature. Early frost in the fall is often considered necessary to provide the best display. With the warming climate, first frost dates have been pushed later into the season. My garden records reveal that only in three years out of the past 17 has the first hard frost been prior to Oct. 5. In decades past, first frosts typically occurred in mid to late September. This year’s first hard frost in my yard was on Oct. 10, too late to impact foliage earlier in the month.
The more dramatic climatic influence this year was the sustained summer drought. Some leaves that didn’t get enough water turned brown and dropped early. Any color that did appear was duller than usual.
There are a few exceptions to this phenomenon. The ornamental shrub burning bush, also called winged euonymus (Euonymus alatus) is one of them. You may have seen this flaming scarlet bush around your neighborhood, or perhaps you have one in your yard. This year, they have been as vibrant as ever. Perhaps because they turn color later, recent rains and cool weather contributed to their showiness.
However, their beauty comes with a price. Burning bush, which originated in Asia, is a non-native, invasive species. That means that it has the capacity to spread readily and outcompete native plants, diminishing regional biodiversity.
Most people are not aware that this plant is on the “prohibited” list compiled by the New Hampshire Department of Agriculture, Markets and Food Plant Industry Division. This means that legally, “No person shall collect, transport, import, export, move, buy, sell, distribute, propagate or transplant any living and viable portion of any prohibited plant species, which includes all of their cultivars and varieties.”
Many burning bush shrubs were purchased and planted before this law was enacted. That doesn’t stop the shrub from spreading. Birds are accomplices in this process. They eat euonymus berries and deposit the seeds with their droppings, sometimes quite a distance from the source. Thus, the spread of the bushes may extend far from the source of the seeds.
Evidence of this is easily seen in the fall when the leaves are red. Though the shrub thrives in sunny yards, it also does well in the understory of a forest. Scanning woodlands near suburban neighborhoods may reveal a haze of red foliage stretching beneath the canopy of trees, choking out native shrubs and herbaceous plants that are part of the local ecosystem.
To reduce the spread of this tenacious invader, it is recommended that the bush be removed and destroyed. Most homeowners are reluctant to do so because they enjoy its beauty. However, there are several native (and non-invasive) shrubs that also display gorgeous red foliage in the fall. Highbush blueberries and various species of viburnum are examples.
Before the beautiful red leaves drop, take note of any burning bush on your property. Consider making a change before next autumn. One less burning bush can mean hundreds of fewer offspring. Your actions will make a difference for native plants and wildlife.