UNITED STATES—Autumn foliar color eventually gets messy. Actually, any deciduous foliage can become messy during its autumn defoliation. Color is not a prerequisite. Some deciduous foliage remains green through the process. Furthermore, some evergreen foliage contributes to the mess. A few evergreen species shed a bit more as the weather becomes more wintry.
Contrary to popular belief, deciduous vegetation is neater than evergreen vegetation. It only seems to be messier because it defoliates completely at once. Also, such complete defoliation exposes bare stems. Evergreen vegetation sheds slower throughout the year. As it replaces old foliage with new, it sheds more in seasonal phases, but incompletely.
Deciduous leaves also seem to be messier because they are generally bigger. They do not disintegrate into landscapes as efficiently as tiny evergreen leaves do. They require raking from lawns, as well as groundcover that can absorb smaller leaves. So, they fall most abundantly, and dissipate least efficiently. That is why defoliation is so very messy.
No foliage is perfect.
Defoliation of deciduous foliage occurs at both the best and worst time of year. It allows more warming sunlight into homes and gardens while the weather is cooling. It leaves deciduous trees more resilient to eventual windy, wintry weather. However, it gets messy while the weather begins to get less conducive to gardening. Summer is about finished.
It truly is ironic. Rain and wind will eventually dislodge the last deciduous foliage during winter. Rain is also why this same foliar debris must not clog eavestroughs and gutters. Yet, it is why removal of such debris can be such an unpleasant chore. Removal of foliar debris from hardscapes is also important. It stains and gets slippery if dampened by rain.
While defoliation decreases shade above, it can increase shade below. Accumulation of foliar debris can detrimentally overwhelm turf and groundcover. Some large leaves can do the same on top of dense shrubbery. Fungal pathogens proliferate within the dark and stagnant dampness below such debris. Shade from such debris inhibits photosynthesis.
Highlight: Box Elder
Leaves of three, leave it be, unless one can see that it is a box elder tree, Acer negundo. This is the most common of the North American maples. It is native to all American states except for only Alaska and Hawaii. Yet, it is also unique as the only maple with pinnately compound leaves. Typical leaves have three leaflets, but might have as many as seven. A few rare maples have palmately compound leaves.
Although common in the wild, box elder is rare within refined landscapes. It grows fast to about 40 feet tall, but does not live for much more than 50 years. It typically develops a few plump trunks with casually irregular form. Unfortunately though, such form becomes structurally deficient with age. Autumn foliar color is unremarkable yellow or brown here.
However, a few garden cultivars display distinctly colorful foliage for Spring. ‘Flamingo’ is the most popular cultivar. Pink variegation of new Spring growth fades to white. ‘Auratum’ displays bright yellow new growth. ‘Violaceum’ displays smoky blushed new foliage with purplish red floral tassels. After pollarding, such cultivars are more compact and colorful, but lack floral tassels.
Tony Tomeo can be contacted at tonytomeo.com.
