Plant Lovers' Almanac: Trees with needles have fall colors too

Along Lake Michigan at the tip of the Leelanau Peninsula in Northport, Michigan, last week, we were treated to the white bark of paperbark birch and the smooth, silvery bark of American beech with its mellow yellows and tans of fall foliage color.

More ominous were the hints of beech bark disease, a complex plant disease involving interactions of the Nectria fungus and beech bark scale insect. Fortunately, not a big deal in Ohio to date, but a terrible sight in many Michigan and Pennsylvania camping grounds where beech trees lay on the ground.

More felicitous were the bright red woodland berries of winterberry holly, also appropriately known as Michigan holly.

Back to Ohio for a series of attractive maples: Korean maple, a striped maple hybrid, and three-flower maple in my backyard and the drooping leaves and pumpkin-like fall color of black maple at Secrest Arboretum in Wooster.

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Seasonal needle coloration

In addition to the maples and other usual fall color favorites with deciduous foliage (trees that lose their leaves in the fall), it is also a time to notice and enjoy the fall color of “narrow-leaved” trees, those with needles and scales for leaves.

First, it is important to note that pine and spruces and firs are not “evergreen” in the sense that they never lose leaves; this is easy enough to see since there are obviously old and brown needles under the trees. Though these trees retain green needles they lose older, inner needles each season, yellowing, browning and falling.

This natural phenomenon is easiest to see on eastern white pine now because they color and drop 1½-year-old needles each year in a short period of time in September and October.

This natural browning of older foliage is also noticeable for the scale-like leaves on arborvitae in woodlands and landscapes, these brown inner leaves looking as if there is a disease, but actually it is natural discoloration.

Finally, there are plants known as “deciduous conifers,” bearing needles that all drop in the fall, trees such as dawn redwood, baldcypress and larch. In my backyard is a fourth deciduous conifer that we see in Ohio – goldenlarch (Pseudolarix amabilis), with lovely yellowing leaves soon to become mulch.

Maidenhair fern

There are over 250 species of maidenhair ferns worldwide. The genus name of Adiantum is derived from the Greek for “unwetted,” referring to the fact that water easily sheds from the tiny, delicate foliage.

Graceful, fanciful, lacey: These are the adjectives for this fern favorite of many. Another feature is the wiry black connective stipes of the plant, often appearing as a circlet atop the fern body.

Humic, well-drained soils and sites near rocky faces are where you see it outdoors, but maidenhair ferns grow well indoors as well, though keeping up relative humidity is always a challenge. Last week in the Leelanau Peninsula we saw as many of the usually sparse maidenhair fern patches as we have ever seen; visit and hike this fruit-growing area north of Traverse City.

Spotted knapweed

As I wrote up this item last week, our Cleveland Guardians pitcher had just struck out another Yankee in the American League Division Series. Spotted knapweed, an invasive species pest for many land managers, is now classified, remarkably, as Centaurea biebersteinii. The pitcher, of course, was Shane Bieber, though Bob Costas misnamed him Justin Bieber! “All That Matters” is that Shane was “Confident,” and we did win that game. But back to spotted knapweed …

… Notice that it is in the genus Centaurea. That is one reason why for years I misidentified spotted knapweed while on walks in Michigan; I used to call it bachelor’s button, thinking that I was seeing escapes from gardens of the popular Eurasian bachelor’s button, Centaurea cyanus or cornflower. Alas, spotted knapweed is not so well-respected. It is a widespread invasive species of concern.

Though the pink-purple frilly flowers are as attractive as bachelor’s buttons, it invades prairies, oak savannahs and dunes, and when extensive in dry areas contributes to increased runoff and poor water retention. It invades into many areas where it is unwanted, is not palatable to wildlife and is considered “allelopathic” to native plants, meaning it produces chemicals that damage other more desirable plants, resulting in colonization of more – spotted knapweed.

It is considered a problem plant in Ohio pastures, where it is often casually mistaken from afar for the bluer chicory, thistles (I have misidentified it as such as well), red clover and even asters.

It will appear as a basal rosette of leaves at first, with flowers arriving in the next year or even longer, subsequently acting as a biennial or semiperennial.

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Sumac

If you have driven along highways in the past month you have been graced by the spectacular patches of sumac, with their yellows, oranges, deepening reds and purple fall color. Sumacs, in the genus Rhus, are a quite versatile genus: from those spectacular staghorn sumacs (Rhus typhina) of the roadsides and cutleaf cultivars used as specimen shrubs in landscapes, to the culinary sumacs such as Rhus coriaria used as a spice in Mediterranean cookery and for a lemony drink. Another, fragrant sumac (Rhus aromatica) is an increasingly popular landscape plant with cultivars, such as ‘Gro-Low,’ used as a groundcovers

Rusty red sumac fruits are also widely used in dyes, and there are many herbal medicines using some of the over 200 species of Rhus worldwide. Rhus is in the cashew family, the Anacardiaceae, and like many members of this family, from cashews to papayas, they may cause allergic reactions in some people.

Which brings us to the white-fruited poison sumac, which was once classified as Rhus vernix but is now known to not be all that closely related to Rhus species. Rather, it is in the genus Toxicodendron, along with fellow travelers in the Anacardiaceae, poison ivy and poison oak.

As for me, I most love the horticultural and highway beauty of sumacs, especially staghorn sumacs, which naturalist Carolus Linnaeus in the 1700s described with “Ramis hirtis uti typhi cervini,” meaning that the branches are rough like antlers in velvet. And as author Jean Hersey wrote: “September is a sweep of dusky, purple asters, a sumac branch swinging in a fringe of scarlet leaves, and the bittersweet scene of wild grapes when I walk down the lane to my mailbox.”

As with our stirring baseball autumn: “Welcome to the Show” of fall colors.

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Jim Chatfield is a horticulture educator and professor emeritus at Ohio State University Extension. If you have questions about caring for your garden, write to chatfield.1@osu.edu or call 330-466-0270. Please include your phone number if you write.

This article originally appeared on Akron Beacon Journal: Plant Lovers' Almanac: Trees with needles have fall colors too