Butterfly bushes (Buddleia) are shallow-rooted beauties that need plenty of elbow room in the garden to really show off. Because they’re such vigorous growers, they can quickly spread into spots where they might not be welcome. So, the big question is: do you need a root barrier to keep them in check?
What exactly is a “shallow-rooted” plant?
When we talk about shallow-rooted plants, we mean their root systems stay pretty close to the soil surface. Instead of sending down deep taproots to anchor themselves, these roots spread out like a fan just a few inches underground. Don’t let the “shallow” part fool you, though—these roots are powerful! They can crowd out neighboring plants, lift up pavers on your garden path, or even cause cracks in nearby walls if they don’t have enough space.
Does your Butterfly Bush need a root barrier?
While Butterfly Bushes are shallow-rooted, they don’t actually spread through underground runners (rhizomes). Their main way of taking over the neighborhood is through the thousands of tiny seeds they drop, which the wind carries everywhere. However, their root systems are very expansive. This is why you need to give them plenty of clearance from other plants, walkways, fences, and walls. If you’re planning on planting a Butterfly Bush hedge, make sure to leave at least 30 inches (80 cm) between each shrub. The good news? You don’t need a heavy-duty root barrier like you would for something invasive like bamboo.
How to properly dig up a Butterfly Bush
Because of that wide, shallow root system, you have to be a bit careful when moving one. If it’s a small plant in a container, repotting is a breeze. But for older shrubs established in the ground, you’ll want to take a gentler approach. The best time to dig them up is during their dormant phase starting in late fall, or in early spring before the new growth starts. Here’s my step-by-step guide:
- Mark a circle around the shrub with a diameter about two-thirds the height of the plant.
- Use a garden fork to thoroughly loosen the soil within that circle.
- Prune the branches back by about one-third.
- Tie the branches together loosely to make the plant easier to handle.
- Use a spade to dig around the circle, going about a full blade’s depth into the ground.
- Keep loosening the soil with your garden fork, trying to get as deep as possible.
- Once the shrub feels loose and moves easily, you can lift it out of the hole.
- Depending on how big the root ball is, you might want to grab a friend to help with the heavy lifting!
Make sure you have the new hole ready to go before you start digging. Once your Butterfly Bush is in its new home, give it a good soak and keep watering it daily for the first few days to help it settle in.
