Garden Notes: Lovely autumnal colors

Continuing the harvest tasks.


It seems sudden, like — overnight: Aronias dripping with ruby fruit, hollies winking red, and sumac’s scarlet foliage topped in crimson velvet cones. In the rain, the fig and the native witch hazel are draining of green, leaving behind a fine yellow.

Seasons and seasonal change are assets of our region. Cold air is needed to produce fall color, and recent nights have been brisk. The sudden, overall look is russet, but other lovely autumnal colors are head-turners. After a summer that was thankfully very green, the change exhilarates the senses.

A roadside native, agrimony (Agrimonia gryposepala) is growing beside our road. Yay! Along most of its length, the wild grape, checkerberry, viburnum, and various asters and goldenrods are succumbing to bittersweet, honeysuckle, Euonymus alata, and miscanthus grass, carried here by winds, birds, and by road-repair fill. The bittersweet especially is a mile-a-minute strangler, and is pushing through the sickened, sparsely leaved beeches into the upper canopy.

Looking around, I found the magnolias’ pods. It has not been that many seasons since these magnolias have begun producing them. The presumption is that setting seed equals well-established, so it is encouraging. As pods ripen (or even explode! as some plants’ and trees’ seedpods are capable of doing), and seeds drop and disperse, they are gathered and stored or consumed by wildlife.

Which brings up a troubling parallel: the loss of the chestnut forests over a century ago, and current beech diseases. As with the collapse of the chestnut system ecology, the implications are enormous. Widespread loss of beeches and their mast would mean in future a lot less food for wildlife and migrating bird populations.

Isoprene: Blame the trees?

Isoprene is a hydrocarbon that many plants and animals, including humans, emit. According to Wikipedia, “Isoprene is produced and emitted by many species of trees (major producers are oaks, poplars, eucalyptus, and some legumes).”

“Yearly production of isoprene emissions by vegetation is around 600 million metric tons …. This is about equivalent to methane emissions, and accounts for around one-third of all hydrocarbons released into the atmosphere … In deciduous forests, isoprene makes up approximately 80 percent of hydrocarbon emissions.” Isoprene emission from forests accounts for the blue color of the Blue Ridge Mountains. 

Why is isoprene of interest? Alarming headlines such as “MSU research shows plants could worsen air pollution on a warming planet” imply that plants can be blamed for human-caused problems, such as air pollution.

Among other factors, it is hypothesized that isoprene functions protectively against heat stress. Isoprene-emitting plants are able to maintain high photosynthetic rates for longer periods when exposed to abiotic stresses. This year is projected to be the hottest year on record.

Isoprene itself is not normally regarded as a pollutant, as it is a natural plant product. However, “A second major effect of isoprene on the atmosphere is that in the presence of [human-caused] nitric oxides, it contributes to the formation of tropospheric (lower-atmosphere) ozone, which is one of the leading air pollutants in many countries.”

In the garden

Common lilacs are blooming in some Island gardens. It does not harm the plants or wreck next season’s bloom; November 2022 saw Edgartown forsythias in bloom, followed by ample spring 2023 bloom.

Poisonous aconites, dependable fall bloomers, were browsed here just prior to flowering. The plants look comical: a lollipop of blue blossom at the top of bare stalks. Deer are foraging closer to houses; place tree-trunk guards and deer fencing. The fawns seem tiny and undersize, possibly from late births this year.

Be alert to rampant vine growth: English ivy, trumpet vine, wisteria, Virginia creeper — all seem to be on steroids, which in fact they may be. Isoprene, mentioned above, a hydrocarbon emitted by plants, turns out to interact with nitrous oxides from human-caused pollutants to enhance photosynthesis, and so many be contributing to the accelerating growth.

Continue with regular Bt applications on cole crops, such as kale and cabbage. Harvested winter squashes’ storage is improved by curing: toughening the rind by leaving in a warm place for a couple of weeks. Smaller varieties, such as my ‘Butterscotch,’ have a shorter storage life. Harvest mint, rosemary, and more to dry for herbal use, teas, and seasoning.

Deeply water root zones of recently planted trees and shrubs before winter. Apply antidesiccants, especially to broadleaf evergreens and conifers that transpire all winter long. Mulch root zones once cold weather arrives.

Take soil tests. Garden beds and soils: Spread compost or mulches, or seed cover crops, over a top dressing of organic fertilizer (soil food). Compost everything, or form a hugelkultur. Prep soil for garlic: Plant enough for kitchen, as well as enough for next year’s seed.

Seedheads of all descriptions, drab or dramatic, are ripening, achieving their purpose. Many are seen with a chipping sparrow or goldfinch clinging to them.

Revisiting beech tree problems

Our atmosphere is now so different from what our planetary life evolved in, that it is imposing major stresses on all Earth’s living systems. Ecological systems, and ecological collapse too, comprise many small pieces, such as beech tree diseases, that form the larger picture, one piece of which is the composition of our atmosphere.

The harms are so pervasive that air pollution in many cases is climate change. Changing rainfall patterns, forest collapse, wildfires, antibiotic resistance, widespread inflammatory and respiratory disease, global pediatric health impacts: All have a basis in bad air (​​

Remind your congressional representatives and senators that they have a duty to listen to our concerns. It is beyond our power individually to alter policy. They are the ones who govern. Once the connections are made clearer between human health problems and planetary health problems, we can simplify our lifestyles far more than we realize.