Homegrown: Trimming scotch broom plants
I have three scotch broom plants that are about 4 years old and growing nicely.
One is the variety “Moonbeam,” which is so beautiful when it blooms.
I’ve never trimmed them and didn’t think I should, but the snow has made them look pretty scraggly and bent over. Will they recover or should they be clipped back to some length?
Lots of people are wondering what to do about some of their garden plants that have been bent over by the heavy snow we got in December.
My general recommendation is to wait because the plant will usually fix the problem by itself, given time.
Now, there are times when the plant needs a bit of help in this department.
Probably the best help would have been to knock the snow off right after it fell. We pretty much never do this (I sure don’t), but if you have a plant that consistently does this and doesn’t seem to spring back in time, this is the way to go.
If, at the end of March, you have a plant that is still bent over or disfigured from the snow, then some light corrective pruning can help.
Cutting or shearing back will remove the worst of the bent-over stuff and lighten the load the branch bears, which will help it stand more erect.
The one drawback about doing this with scotch broom is that you’ll be pruning off some of the flowers for this coming spring.
Broom sets its flower buds in the late spring or early summer of the prior year. Those buds are on your plant right now just waiting for some warmer weather to break open and bloom.
Pruning them off is just a setback for this year, the plant will look great next year, assuming we don’t get another killer snowfall like we did this year.
In the long term, pruning scotch broom gets to be a bit more problematic.
In time, many varieties will get to 6-feet to even 10-feet tall and can become more open and “scraggly” looking.
Once this happens, there’s little you can do to fix this. Pruning an older plant back severely will almost always kill the plant.
These plants retain few, if any, dormant buds down on those older stems to resprout when cut back.
Pruning needs to begin at a fairly young age (you still have time). It consists of selectively pruning back young stems every year to stimulate fresh new growth that will keep the plant full and thick.
The drawback to this is that eventually, you’ll create a plant that has a sheared look to it which may not be desirable in your particular situation.
This more formal look is much different than the more informal, natural look reminiscent of Mormon tea that an unpruned plant gives.
And speaking of shearing, these plants can be maintained for many years as a sheared specimen if you so desire. The only thing to keep in mind is that you’ll have to shear it in late spring right after it’s done blooming.
Pruning in summer or fall risks losing the flowers for the following spring.
The honest truth is that if you really want a more informal plant combined with a full lush look, you’ll have to treat the plant as a short-term project and replace it every 6–10 years.