Rust diseases of plants may of course be devastating, from black stem rust of wheat which contributed to famine after World War I to cedar apple rusts which must be controlled by orchardists and (sometimes) landscapers today. Yet, it must be admitted, they are fascinating. They can be autoecious (occurring on only one host plant) such as may-apple rust commonly seen in spring woodlands, but often they must complete their life cycles on wildly different hosts, such as wheat & barberry, juniper & apple.

 

About a month ago I came upon a rust disease I had not...

Second generation larvae of the imported willow leaf beetles (Plagiodera versicolora) are munching the leaves of wild and cultivated willows in southwest Ohio.  This native of northern Europe was first found in the U.S. in 1915.  Since that time, it has become well established throughout most of the eastern and Midwestern states.  This beetle has a history of periodically achieving population outbreak densities and causing significant defoliation of its namesake host in Ohio.

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With apologies to William Blake and his 1794 publication of the deep-meaning “The Sick Rose” poem, it occurred to me that I was indeed deliberately trying to weaken the pictured rose (multiflora) by mowing in my back lot and continually chopping off the terminal shoot of this rose. In my case, I see this mowing as a metaphor for typically improper topping that I will negatively highlight in my pruning talk at the Cultivate 2016 program a week hence. For trees, top not, you clod-loppers: it releases adjacent buds resulting in hormonal imbalance and tufted, weak growth.

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Probably a decade ago, I brought home a containerized tree, probably from a Secrest Arboretum Plant Discovery Day sale, perhaps as a gift from a friend. It was neglected in its container at the side of our house in northeast Ohio until my wife elbowed me into planting it on a day with little time and I stuck it a few feet away near some old spruce trees. I mostly forgot about it, maybe once a year wondering if this was a volunteer that had sprouted up or if I had planted it, until last year, at about 15 feet tall (yes, I am that unobservant and lazy), when I noticed this tree’s yellow...

This native 1- to 3-foot herbaceous perennial, Asclepias tuberosa (not to be confused with butterfly bush, Buddleia) provides that fairly uncommon sight along roadsides, in meadows and, increasingly in gardens – a bright orange flower. This caught my eye so dramatically decades ago that I had to pull over while driving an interstate highway in Iowa, against the increasingly urgent verbotens of the Herr Professor in the passenger seat. Just had to take a look.

 

It is sometimes called orange milkweed, and Asclepias is a genus with many species that...

The bladder-like galls produced the Sumac Gall Aphid (Melaphis rhois) are just beginning to develop on the leaflet midveins of its namesake host in southwest Ohio.  The galls are currently light green and so small they may be difficult to detect.  However, as the season progresses, the galls will eventually become more evident growing to 1/2 - 1" in length and becoming variegated with areas that are greenish-white bounded by areas that are mottled reddish-pink.

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Every time I see the bristly, lumpy round galls produced by the grape phylloxera (Daktulosphaira vitifoliae) on the lower leaf surfaces of wild grape (Vitis spp.), I'm reminded of the story of how an American saved the French (and European) wine industry.  Some may consider it a return on the favor for the French making it possible for us to have something to celebrate on the 4th of July.

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Chicory is a weed that is in bloom in Ohio right now. It can be seen growing abundantly beside roads and highways. It can also be found in lawns, pastures, fields, and waste places. Originating in the Mediterranean chicory was distributed throughout much of the world where it was grown for centuries as a salad green. It escaped from cultivation in North America and has naturalized and spread throughout southern Canada and the U.S.

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Katsuratree (Cercidiphyllum japonicum) is one of my favorite trees, providing an array of foliar colors throughout the season and a sometimes elusive, but wondrous aroma of crème brulee on fallen Autumn leaves. I could go on and on, but it is better to hear from the master.

Michael Dirr in his “Manual of Woody Landscape Plants” writes of katsuratree: “New leaves emerge a beautiful reddish purple and gradually change to bluish green in summer; fall color varies from yellow to apricot...leaf is shaped like a redbud (Cercis) leaf...the senescing (fall-coloring)...

The irregular, wart‑like light green to reddish-green bladder galls now rising from the upper leaf surfaces of poison ivy are produced by the eriophyid mite, Aculops rhois (= A. toxicophagus) (family Eriophyidae).