Layering tall plants adds height to tight spaces

In recent Plant Man columns, we’ve looked at plants that you might want to avoid because they can become invasive and take over your landscape to the detriment of other plants.
But are there plants that can actually kill? Perhaps alter the course of history? Unlikely as that might seem, a recent book takes a fascinating, if gruesome, look at what the author calls wicked plants. I’ll give a brief review of that book later in this column.
But, thank goodness, most plants are far from evil! Even in a relatively small space, carefully selected plants can increase privacy without giving you a sense of claustrophobia. The trick is layering and including columnar-growing trees that fit the scale of your landscape, as I explain to this reader:
QUESTION: “When I bought my house, it had what I believe are oak trees in one corner of the smallish back yard (total yard size is 0.3 acres, less than half that in the back yard). They have grown very tall, yet thin. I don’t really like them. I’m looking to do the other corner of my yard with a faster growing tree that I can cluster in the corner – like Crape Myrtles (I heard the Dynamite are great). My fence is the standard 4 feet, natural wood.
My questions include: What types of trees will be a good fit for the corner? And how far apart should I plant them? I’m looking for a pretty thick coverage. I heard layering is a good practice. What are some nice medium sized trees or shrubs to combine with the bigger trees? What can I do to improve the existing oak trees? Can I prune to make them thicker, broader? I also have a river birch in my front yard that we planted about two years ago. It doesn’t seem to be growing very fast. Anything I can do to help it out?” – Thomas G. Burgess ANSWER: The oak trees you are describing sound old and scrubby. If that is the case, then there really isn’t anything you can do to thicken them up. Since you have a small area to work with, you should consider trees that are more columnar (narrow) growing such as emerald green arborvitaes and other smaller sized shrubs and trees. The Dynamite crape myrtle is also a smaller growing tree and would work within that sizing. However, if it would receive any shading from the fence, house or oak trees, it will not bloom properly. Crape myrtles need full sun for consistent blooming.
Layering is an attractive way to build privacy from the outside. Layering can be achieved by the strategic placing of taller growing plants such as emerald greens at the back ( they can be spaced approximately 5 to 6 feet apart), coming forward with contrasting colored shrubs such as barberry Sunjoy Gold Pillar, weigela Wine and Roses, Beauty Bush Dream Catcher, or taller growing ornamental grasses. Using colorful perennials on the most inside areas add one last punch of color.
Birches aren’t all that fast growing especially in clay soil. It may take it several years, but it will grow.
And now to those “naughty” plants…
If it was a tabloid-style TV show, it might be called “When Good Plants Go Bad.” However, the new book by Amy Stewart is titled “Wicked Plants” and is a compendium of plants that can kill, injure, torment and cause all kinds of trouble to humans, animals and other plants.
On one level, “Wicked Plants” is simply an entertaining read with plenty of botanical trivia and gruesome stories of plants behaving badly, as you might guess from the book’s sub-title: “The Weed that Killed Lincoln's Mother & Other Botanical Atrocities.”
But there is more than just grisly fun to be found here. On a more practical level, “Wicked Plants” can be a warning about what NOT to plant, or at least what will happen if you do.
As author Amy Stewart says, “These are plants you do not want to meet in a dark alley.”
The Plant Man is here to help. Send your questions about trees, shrubs and landscaping to and for resources and additional information, including archived columns, visit
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