Garden Q&A: The trouble with topiaries
Q: We have a large topiary plant (three round balls on top) in our front yard. It's been there for six or seven years, and we have gone to great lengths to keep it looking nice. Recently, we have noticed that there are some brown (dead?) branches and leaves on the plant. There is, however, still a lot of green on it, which might indicate that it's not dead. Could you offer some advice that might help to revive the plant? Thank you in advance.
A: We should title this column “The Trouble with Topiaries” because you are not alone in having this issue. Topiaries in general require a lot of maintenance. They need regular and judicious pruning as well as careful examination for pests and diseases. Topiaries are forced to grow in a way that is completely unnatural, pruned at less-than-ideal times, and planted in very exposed sites — all practices that serve to stress them out and make them more prone to developing “issues.”
Because so much pruning activity goes into creating and maintaining a topiary, there are lots of open wounds that can serve as an entrance site for various blights and diseases. It is exceedingly important that your pruners are sharp and meticulously clean before any pruning begins. The blades should be dipped in a 10 percent bleach solution or wiped off with rubbing alcohol between each and every cut (see what I mean about topiaries being high maintenance?).
And to put the icing on the cake, though you do not say the type of evergreen that was used to create your topiary, junipers are most frequently used to form the type of topiary you describe, and junipers are inclined to develop a fungal disease known commonly as juniper tip blight. Juniper tip blight causes individual branches to yellow and eventually die. Treatment involves the careful and regular removal of infected branches during dry summer weather.
To prevent spreading the fungal spores, keep your clippers clean, water only in the morning, maintain adequate fertility (but do not over fertilize), provide the plant with good air circulation, and try to do most of your pruning during dry, warm weather. I suspect from the description of your topiary, that juniper tip blight is an issue.
Every two or three years, you should consider fertilizing your topiary with an evergreen-specific granular fertilizer. I like Espoma's HollyTone for my evergreens as it helps maintain the acidic soil conditions evergreens prefer, but your local garden center should have other evergreen-specific options as well.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is www.jessicawalliser.com.
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