Q: I have what they call a dwarf burning bush, and if it's a dwarf I would hate to see its big brother. It's over six feet tall and blocking my window and the view from my porch. What is the best time to trim my big dwarf burning bush? It has flat branches and red berries; it's beautiful in the fall and early winter and I don't want to do anything to hurt it.
- ---Teddy from Harlan County, Kentucky
A. One of the very first articles I found when I did my initial online research on this question explained that 'dwarf' referred to the size of the leaves and not the actual plant, which made sense in terms of Teddy's experience, if not real horticultural sense.
But try as I might, I could NOT find that article again the next day. But I did find lots of more reliable information about "Euonymus alatus compactus", which is the Latin genus and species name for the landscape plant we traditionally call 'burning bush' plus 'compactus' (or in some cases 'compacta') for 'compact'—meaning it IS a true dwarf variety.
Yes, Teddy's 'dwarf' is six feet tall, but that's still within its final height of six to eight, maybe ten feet tall. In the wild world of horticulture, "dwarf" doesn't actually mean 'small'; just smaller than the standard, and the standard variety here gets so big it's sometimes used as a screening plant—or planted in rows to make a giant wall.
As famed horticulturist Albert Einstein once noted, it's all relative. For instance: A couple of my 'dwarf' peach trees would be over twelve feet by now if I didn't prune out the tallest branches every year. But my 'standard' peach trees grew twice as tall and twice as fast.
Now—time to talk about how to prune burning bush; because we also have an email from Reid in Forest Lake, Minnesota, who writes: "How much can I prune my burning bush? It is 20 years old and out of control. If I prune 18 inches, how much will grow back this season?"
Basically, burning bush is a deciduous shrub; one that loses its leaves in winter. And people who want to keep it a manageable size typically prune it back at the end of winter/early Spring every year. That 'every year' part is important; you're always going to get the best results if you give plants an annual haircut as opposed to waiting until they're out of control.
Ah, but pruning at that time of year would limit the number of flowers; and Teddy in Kentucky specifically mentions that he likes the berries…
The flowers themselves are what are typically called "insignificant", meaning that they aren't much to look at—like the flowers on my blue holly; you have to really look to see them. But later in the season every one of those flowers could become a fruit; and each flower did on my holly this past year. Some seasons I only get a few berries, but this winter is out of control. We had a very holly Christmas!
Anyway, Reid in Minnesota can follow the standard advice and prune his shrub back by a third. (In his case, eighteen inches might be conservative depending on the actual size of his plant.) But he should resist the temptation to do more than a third the first time around, and instead plan to prune every year from now on. And because he is in Minnesota, he needs to wait until all chance of frost is gone. No 'late winter' pruning for him, as winter in that part of the country has been known come back and say hello the first week of June.
And Teddy in Kentucky? His BB is a naturally six to eight foot tall plant that's grown for its incredible fiery red fall color. If he needs it to be some kind of extreme bonsai because of the space issue, he should move it or replace it. But if he's willing to compromise a bit, he should be able to keep it a nice five feet tall with annual pruning. But if he wants to really max out the berries, he should move it to a bigger spot. The less pruning you do, the more berries you'll get.
Now, the obvious side question: Could this plant possibly be the burning bush of the Bible?
No. Euonymus species are not native to anywhere near The Holy Land.
But some plant archeologists postulate that the Biblical burning bush was a real plant, most likely in the genus "Dictamnus" (which even sounds like a book of the Old Testament). These plants are native to that part of the world, and produce so much aromatic oil they can spontaneously combust near a heat source—or even just on a hot and sunny day. To quote my giant reference guide called "The Plant Book": "The bush is engulfed in flame, but so briefly that it is not damaged".
Its other common name is (unsurprisingly) 'the gas plant', and was a popular symbol for 16th century French Huguenots, accompanied by the motto: "I am burned but not consumed".
The gas plant family members are hard for a home gardener to find; and they're said to be very difficult to establish. But if you can find one and get it growing, it's hardy down all the way down to Zone 3. That means you could theoretically grow the REAL burning bush in Minnesnowta!