With its stunning blue or white blooms, the Blue Potato Bush (also known as the Gentian Bush) is a total showstopper in any summer garden. If you’re feeling fancy, you can even prune it into a beautiful “standard” or tree-like shape. Just a heads-up, though—this plant can be a bit of a diva if it doesn’t get its way!
Does my Blue Potato Bush really need regular pruning?
The short answer is yes! If you want a lush, bushy plant covered in flowers, regular pruning is non-negotiable. The best time to give it a good trim is in the spring, right as you’re bringing it out of winter storage. However, if you’re tight on space in your garage or basement, you can also cut it back before it goes into winter hibernation.
How to prune: A step-by-step guide
Start by thinning out the “crown” or canopy. Look for any branches growing inward toward the center and snip them off right at the fork. Next, clear out any dried-up or sickly-looking twigs. Once that’s done, go ahead and shorten the one-year-old shoots—those are the ones that bloomed for you last season.
Can I give it a “hard” prune?
I wouldn’t recommend it. The Blue Potato Bush isn’t a fan of radical hacking. Even if your plant has grown like crazy, it’s better to be cautious. While older plants handle pruning a bit better than youngsters, you should never cut away more than half of the plant at once. The younger your tree is, the more gentle you should be with the shears.
Tips for maintaining a “standard” (tree-form) bush
If you’re growing yours as a high-stemmed tree, you’ll want to keep your garden shears handy all summer long to keep that canopy looking tight and tidy. Don’t be afraid to trim back any flowering shoots that start sticking out and ruining the shape.
For any new side shoots popping up along the main trunk, you can actually just pinch those off with your fingers as soon as they appear. Then, during your big spring prune, focus on shaping the canopy back into a nice, neat ball.
The Quick Takeaway:
- Regular pruning is the secret to dense growth and tons of flowers.
- Be gentle—never cut back more than 50% of the plant.
- Spring is the best time for a major prune.
- Stick to light “touch-up” trims during the growing season.
- For tree-forms, pluck off trunk suckers as soon as you see them.
Pro Tip: If you skip the pruning, your Blue Potato Bush might decide to go on strike and stop blooming altogether!
