UNITED STATES—Colorful foliage is always present. After all, green is a color, even without any other color or variegation. Defoliation of deciduous foliage during autumn reveals evergreen foliage beyond, even if fading through winter. Immediately prior to defoliation though, deciduous foliage of quite a few species temporarily becomes spectacularly colorful autumn foliage.
Whether deciduous or evergreen, foliage that is most colorful during spring and summer contains chlorophyll. Regardless of how variegated, reddish, purplish, yellowish or other color it might be, it is also green to some degree. It could not be photosynthetically active otherwise. Colorful autumn foliage exhibits brighter color as its chlorophyll decomposes.
Autumn foliage is most spectacular where it is native, such as New England. Much more of it inhabits forests than home gardens. It is not spectacular within forests here because only a few sparsely dispersed native species produce impressive foliar color for autumn. Its naturally local scarcity likely contributes to its limited popularity within home gardens.
Several species provide colorful autumn foliage within mild climates.
Locally mild weather also limits the popularity as well as the potential of autumn foliage. Many of the most colorful maples of New England merely turn blandly pallid yellow prior to hastily premature defoliation here. However, several other species develop exemplary foliar color in response to minor chill and seem to be as happy here as in New England.
Chinese pistache, sweetgum, flowering pear and ginkgo are four trees that most reliably provide autumn foliage here. Crape myrtle is a smaller tree that is almost as reliable, and blooms splendidly for summer. Persimmon gets as colorful as Chinese pistache, with an abundance of fruit. Boston ivy is a vine with color that is comparable to that of sweetgum.
Of course, even the most appealing of plants are not perfect. Their innate characteristics are relevant to selection. For examples, trees occupy significant space. Ginkgo becomes bright yellow, but without any other color. Sweetgum produces obnoxiously prickly fruits. Flowering pear is susceptible to fireblight. Boston ivy clings to surfaces and ruins siding, paint and fences.
This might be the most spectacular and most reliable of autumn foliage available locally. Sweetgum, Liquidambar styraciflua, begins to develop a brilliant blend of yellow, orange and red in response to the earliest mild chill of autumn. It defoliates slowly to retain much of its colorful foliage through the earliest rain and wind of winter, and perhaps even later.
Sweetgum leaves are palmate, and about four inches wide, with five pointed lobes. One very rare cultivar has hierarchically lobed leaves, with lobes on lobes. Another has blunt lobes. Some cultivars as well as individual trees favor particular foliar colors for autumn. ‘Burgundy’ exhibits more dark red color than typical, and retains foliage later than typical.
Mature trees can grow 50 feet tall but are not very broad. They can get taller and lankier to compete with other tall trees. Their upright form conforms to grove arrangement within large landscapes and parks. Unfortunately, their aggressive roots can displace concrete. Their branches can be structurally deficient. Their spiky and hard fruit can be obnoxious.
Tony Tomeo can be contacted at tonytomeo.com.