Q: Our young and once healthy peach trees have been appearing less than healthy as the summer has progressed. They are producing fruit, but I first noticed the black things on the bark that I thought ...

Scale insects are one of the most common and tenacious pest of ornamental plants. “Scales are tiny insects that appear ...

My magnolia had a problem with magnolia scale last year. Will it come back, and should I take some action to protect my tree? The leaves were covered in a black mold late last summer. — Frank Butler, ...

Q: I just bought a cherry tree and found it has red shiny spots on most of its leaf stems. I sprayed with a fungicide but see no result, those spots look permanent. Are they OK? Is there some ...

We have a lime tree that we winter indoors. In March, the tree developed about 60 limes. Also during that time, the tree developed scale insects. We purchased a nontoxic solution, which somewhat ...

We see it all in the Plant Clinic, and this summer we’ve been seeing a lot of Acanthococcus lagerstroemiae or crapemyrtle bark scale. This invasive insect from southeast Asia first appeared in the ...

Magnolia scale is one of the largest soft scales found in the U.S. and feeds on the sap of magnolias, particularly star magnolia, lily magnolia, cucumber tree magnolia, and saucer magnolia. Tuliptree ...

correctionIn an earlier version of this article, the last name of a Smithsonian Gardens arborist was incorrectly stated. He is Jacob Hendee, not Jacob Hender. The article has been corrected. Spring ...

Maple trees in urban environments show signs of stress due to the urban heat island effect. Impervious surfaces like pavement retain heat and disrupt water absorption, stressing trees and making them ...