Oak leaf

Leaves Are Wearing Out

Have a look at the leaves of trees around you. Chances are pretty good that they don’t look healthy. Fading leaves with holes and other insect signs, mold and other fungi and a generally bedraggled look are normal at this time of year.  What is wrong with the tree? Probably nothing. Leaves look bad at […]

Lightning struck tree

Death of an Oak

This beautiful old oak tree was struck by lightning last September. Within 2 days, it had completely wilted and showed no signs of life. Sudden death due to lightning is uncommon in trees, especially after the end of the growing season. Several experts recommended leaving the tree until spring to see if it showed any […]

The green terror emerges

The emerald ash borer, a shiny green beetle, is emerging from ash trees all over the eastern US and Canada.  The beautiful little beetle, part of a group called “metallic wood boring beetle” was introduced in packing material from China around 1990.  Carried throughout the region by people moving firewood, the beetle threatens to eliminate white, […]

Holly leaf

A Question of Timing

Leaf exchange in holly We know that trees usually lose their leaves in autumn, which is why we sometimes call the season fall. A few trees do things differently, though. One of those is American holly, Ilex opaca. Holly is a tree that we usually call evergreen because it stays green year-round. But if you […]

flowering dogwood inflorescence

When is a flower not a flower?

Many trees are full of showy flowers at this time of year. A close look at these flowers can be quite rewarding. Flowering dogwood is one of our most popular flowering trees, but those beautiful white blossoms hide a secret. Take a close look at a dogwood tree and you will see that the showy […]

Showy flowers

Flowers, Pollen and Allergies

Is that tree causing your allergies?  That pretty tree with the white flowers?  That pine tree covering your car in green film?  Nope. It’s the trees you don’t see that are getting you. This is the height of allergy season. You can feel it in your sinuses and see it on your car windows. Huge […]

In Praise of Black Locust

All over Kentucky, there is an explosion of the amazing white flowers of black locust, Robinia pseudoacacia. This is a tree that is both loved and hated. While it is in flower, I thought we’d take a few moments to talk about the virtues and sins of black locust.   Here are the things we […]

sugar maple flowers

More tree sex – sugar maple

Have you seen the sugar maples in flower?  In Kentucky, they are flowering right now, but you need to look closely to see them. The flowers are not very show, their pale green blending with the green riot that is spring.  These interesting flowers will reward the careful observer.  Sex in maples is complicated. Even […]

The Sap Is Rising

“The sap is rising” is an often heard description of early spring. If you cut into the stem or branch of certain trees – sugar maple, birch, hickory, walnut, or sycamore – on a cool spring day, you may see sap dripping from the cut end, or an icicle of sap forming.  The sap is slightly […]

What good are knees to a baldcypress?

What good are knees on a tree? Baldcypress famously has these odd structures that stick out above the water line. Botanist Francois André Michaux saw knees on baldcypress trees and, in 1819, said “No cause can be assigned for their existence.”  Nearly 200 years later, what do we know about the function of this strange structure? […]

Leaves in a Warm Autumn

In a warm autumn, as we are having in 2016, leaf color change is slowed down. Instead of a quick display of color, we often see slow development of color, muted colors, and mottled colors within a single leaf. We had the same conditions in 2014. Trees use photoperiod, or day length, to determine when […]

Keep Growing Until We Have to Quit – The Yellow-Poplar Strategy

Trees are generally very conservative in their growth habits. They often go to extremes to avoid rare events such as an early frost or severe drought. This is especially true of shoot growth. Although we think of trees as growing all summer, most trees only grow in height for a few weeks. Flowering dogwood sets […]

water drops on a leaf

Water droplets on leaves

Look at the two leaves below. The oak leaf has flat, rather dull drops. The redbud leaf has round, shiny drops.  If you look around at leaves after a rain, you will see some leaves with round, shiny raindrops like the redbud, while other leaves will have flat drops like the oak, or will shed […]