Tree of the Week

Boxelder, Acer negundo L.

DISTINGUISHING CHARACTERISTICS: Leaves once-pinnately compound, opposite; leaflets 3 to 9 in number (usually 3 or 5), ovate, sometimes shallowly lobed, 2 to 4 inches long, the margins entire or coarsely and shallowly toothed. Winter twigs moderate in diameter, green or purple, usually coated with a white waxy substance; leaf scars V-shaped with 3 bundle scars, opposing leaf scars joined at their ends and thus encircling the twigs, the junction prolonged upward into a short point on each side of the twig. Buds ovoid, densely white-hairy, 1/8 to 1/4 inch long with 2 or 4 visible scales. Flowers very small, greenish, dioecious, apetalous, appearing just before the leaves  in spring; staminate long-stalked in umbellike clusters; pistillate in racemes. Fruit a pair of samaras joined at the base; wings 1 to 2 inches long, drooping; samaras ripening in autumn, often remaining on the tree through winter. Bark gray or brown, furrowed with scaly ridges.

SIMILAR TREES: Ashes, the only other common trees with opposite, pinnately compound leaves, have 7 to 11 leaflets and single, paddle-shaped samaras. Easily distinguished from other maples and ashes in winter by its greenish or purple twigs, white-hairy buds, and upward-poiting leaf scar junctions.

IOWA DISTRIBUTION: Native throughout the state, occasionally cultivated.

Forest and Shade Trees of Iowa (Third Edition), by Peter J. van der Linden and Donald R. Farrar

Gardening in October

Tuesday, October 3

On a crisp, clear morning like this, I sometimes wish I could stay home forever. Just sitting on the back steps, taking it all in. The grass spangled with yellow walnut leaves. The yard framed with golden walnut trees .A shaft of sunlight angling through the open branches, suffusing the air and a piece of the big vegetable bed with its luminous beam. Yellow and green, yellow and green. With a few spots of pale brown among the pin oak leaves, and several specks of purple and pink among the pear leaves, and a few hints of orange amid the maple. So striking a leafscape, a landscape, I was momentarily transfixed by it.

Carl H. Klaus, My Vegetable Love: A Journal of a Growing Season

Butterfly of the Week

Silver-spotted Skipper

Epargyreus clarus (Cramer [1775])
Status: Common breeding resident
Flight: Multiple brooded, flying throughout the growing season. It is most often encountered from late May to mid July.
Distinguishing features: The Silver-spotted Skipper's large size, dark brown color, medial gold band on the upper and lower fore wing, and large silver band on the lower hind wing make it easy to identify. Wingspan: 4.5-5.5 cm.
Distribution and habitat: Map 5. Found throughout the state in a wide variety of wooded habitats. It was first reported in Iowa from Denison in Crawford County in 1869.
Natural history: The Silver-spotted Skipper is an extremely strong flyer. It is very pugnacious and will even dart at small birds. While Paul Opler and George Krizek (1984) report that its larvae consume a large variety of common woodland legumes, no favored host plants have been recorded in Iowa. It is likely that it eats a large variety of common woodland legumes, such as black locust, honey locust, hog peanut, and tick-trefoil.
Questions: Is the pugnacious behavior of perching adults toward flying intruders part of the courtship pattern pr a form of territoriality? What is the selective advantage of the large silvery-white spot on the vertical hind wing?

The Butterflies of Iowa, by Dennis W. Schlicht, John C. Downey, and Jeffrey C. Nekola

September Gardening Tip

Saturday, September 23

I could tell the freeze was coming for sure, when Pip and I were out walking at midnight, the sky clear, the stars bright, my breath condensing in front of me as he pulled his way around the block, energized by the cold and his purblind will.

Come morning, I jumped out of bed, expecting to find the lawn completely rimed with frost, a thick white coating on it, but instead found just a trace on scattered portions of the back yard. And a close-up check of the unprotected plants revealed they hadn't been nipped by it, not even the okra, native of Africa.

Carl H. Klaus, My Vegetable Love: A Journal of a Growing Season

This Week in Iowa Nature

The Harvest Moon, familiar in song and story, is the full moon closest to the autumnal equinox.

Jean C. Prior and James Sandrock, The Iowa Nature Calendar

Habitat of the Month

Western Mountain Meadow
Mountain Bluebird

In ancient times, powerful natural pressures underneath the earth's surface pushed and folded the land above. Over hundreds of years, glaciers—huge, grinding plates of ice—and rivers carved out canyons and gorges and the rugged mountain ranges we see today. Many habitats are found here, from treeless mountaintops to the thick forests and open meadows below.

The mountain bluebird, a fast-flying little songbird, lives near mountain meadows. If a flash of bright sky-blue streaks by, you've probably seen an adult male bluebird.

In the meadows, bluebirds find insects to eat. When it is time to nest, they fly to the forest edge to look for trees with holes in their trunks.

Bluebirds migrate south to warmer places for the winter at the same time that the leaves on the aspen trees turn golden.

As more people cut down trees and build houses near mountains, bluebirds find it harder to locate places to nest. If you live close to a mountain meadow, you can help by building boxes for bluebirds.


Where Do Birds Live? by Claudia McGehee

September Gardening Tip

Thursday, September 21

Staring at the sheathed tomato plants this morning, taking stock of what still needed protection, I was struck by how different they look from row-covered peppers. The ghostly white sheets of spun-bond polyester completely hide the pepper plants, so I can't see them unless I hunch over and peer through the covers. Even then I can detect only their blurred shapes and an occasional leaf or fruit close to the surface of the cloth. But the clear plastic sleeves on the tomato plants hide nothing. In fact, they reveal everything -- stems, leaves, and pendulous fruit -- like a see-through woman's sheath, an in-your-face bit of haute couture from an Italian or Parisian designer. Come to think of it, the row of tomato plants looks somewhat like a parade of avant-garde bridesmaids, each one sheathed in a billow of plastic from head to toe, from the gathering at the top of the one at the bottom. Up close, the effect is even more daring, what with all the holes punched in the plastic to keep the plants from overheating on warm sunny days. But there is no danger of overheating today. Overcast skies, light rain, temperatures in the mid-forties, and a northwest wind, like the end of October or November. Thirty degrees below normal for this final day of the traditional summer season. One of the coldest ends on record.

Carl H. Klaus, My Vegetable Love: A Journal of a Growing Season