In my youth, old timers claimed that gardeners could expect frost in a specific area six weeks after goldenrods first blossomed there. For instance, an old friend swears that if goldenrods bloom in his fields on Aug. 17, frost will hit his garden by Sept. 28 exactly 42 days later.

In my humble opinion, that 6-week rule has myriad exceptions, but people who believe this frost rule get mighty belligerent at anyone questioning their homily aphorism. I’m one of those people with a mind for details and dates, though, and notice such trivia. The six-week blossom rule does work in some years but don’t bet your life savings on it, particularly the 42-day time line. It might be 6 1/2- or 7 1/4-weeks.

Right now, bees are hitting goldenrods for pollen, but these blossoms are already starting to turn a dry, textured brown. Folks gathering dead flowers for a kitchen centerpiece will soon pick these long-gone goldenrods.

New England asters with strong blues and purples dot roadsides and gravel parking-lot edges now. I once knew a serious, amateur botanist and aggravated the hell out of him by calling these asters “baby daisies.”

This normally quiet man would yell, “They’re New England asters, you knot-head!”

Red-maple leaves often turn red or yellow each fall, and a red maple in the same soil and sunlight may produce bright yellow leaves, while the same species growing immediately beside it blazes red. Other red maple leaves change to pink, but some red-maple leaves become yellow with bright-red, round spots that fool hunters, following blood droppings from a wounded deer. These spotted leaves have tricked me, while I was tracking.

White-ash leaves take on a purple hue, and one big ash grew by a brook behind my boyhood home. Leaves on a black ash get yellow, and Mainers often call the tree “brown ash” or “basket-making wood.”

In my early days as a free-lancer, I sold an article to a northern New England magazine on the topic of what color leaves turn in fall. I received a nice check for the effort and for a few years, kept selling the rewritten idea to different magazines each fall. It was ever so simple, because I’d think of trees around my childhood home, remember what color leaves changed in autumn and come up with new memories. Then, I’d write my annual article.

After the fall equinox, plenty is happening in Maine, beginning with this: Dandelions, a plant that intrigues me, have once again bloomed on lawns after six or more weeks of no yellow blossoms. The species originally came from Eurasia — an invasive but edible plant. Lawn lovers hate dandelions, but wild-food gatherers adore this high-vitamin green as well as the coffee-like beverage, made from its dried root.

Several years ago, I lived in a different home with no dandelions on my lawn but could see the plants marching down the road via other lawns. Eventually, they invaded my lawn, but I did not poison my dandelions. However, the yellow blossoms started disappearing on their own, proving that nature often takes care of itself.

After a summer of no phoebe sounds, they have started again. This species jacks it tail up and down like someone working an old-fashioned, water-pump handle in a different century. Besides that ID indicator, phoebes sport a black bill and have subdued to no wing stripes, a drab species.

Naturally, we call the species “phoebe” after its call. In my humble opinion, though, black-capped chickadees enunciate “fee-bee” better, but I wouldn’t debate this point.

Most of us remember that eastern pewees have two white wing stripes and no eye rings, and we love the “pee-a-wee” call of this species around our homes or while we bicycle or fish along a favorite river or large stream.

So many plants in New England and the rest of the U. S. came from Eurasia, including many clovers, Queen Anne’s lace, oxeye daisy (the common daisy), dandelion, hawkweed, yarrow, Japanese knotweed, St. Johnswort, etc. In fact, nearly 1,000 introduced plants have become naturalized in New England.

On my first day of bicycling the Kennebec River Rail Trail between Augusta and Gardiner, I noticed that most ground plants along the trail had come from Europe and Asia. In the 16th and 17th centuries, these plants first arrived in hay for livestock and from seed packets for gardens, and they escaped into the wild. We now accept them as natives.

Even honeybees and earthworms came from the Old World, and honeybees now reign as Maine’s state insect — an introduced species! Settlers even mixed Old World red foxes with North-American red foxes, because early settlers loved hunting Reynard from horseback with trailing hounds and wanted a larger fox population to chase.

September is a grand month for studying Mother Nature, because temperatures are so pleasant and biting bugs more scarce. But make no mistake. Astute observers notice cold weather stealing into Maine an inch at a time now, and many of us know warm hikes and pleasant pedals won’t last long. Winter will soon be breathing down our proverbial necks.