The Globe Maple (also known as the Globe Norway Maple) is what we call a “heart-rooter.” This means its root system grows quite shallow and wide, sometimes even popping up above the soil line. If you’ve got roots poking through your lawn, don’t panic! I’ll walk you through how to safely prune those stubborn roots or, better yet, how to hide them with some beautiful underplanting.
How much space do Globe Maple roots actually need?
“Heart-rooting” describes a root ball that spreads out wide just beneath the surface. While a few roots might dive down about three feet deep, the overall shape looks a bit like a heart—hence the name.
The best way to avoid a stressful root pruning session later is to give your tree plenty of elbow room when you first plant it. To keep your hardscaping safe, plan for at least 6 feet of clearance from paved paths or patios. If you’re planting near a wall or the side of your house, you might want to leave up to 12 feet of space unless you plan on pruning the canopy very regularly to keep its growth in check.
Can you safely prune Globe Maple roots?
If those roots are starting to lift your sidewalk or cause a tripping hazard, you can consider pruning them. However, you need to be careful not to shock the tree. Here are the ground rules:
- Wait until the tree has been established for at least 5 years.
- Only prune in the fall.
- Choose a dry, overcast day.
- Never remove more than one-third of a single root.
- Always prune the canopy back in the same proportion.
Start by carefully digging around the problematic root to expose it, then trim off no more than a third of its length. Fill the hole back in with fresh soil and give the tree a good, deep soak. Crucially, you’ll need to trim back the branches of the crown by the same amount you took off the roots. Why? Because a smaller root system can’t “feed” a full-sized canopy, and you don’t want the tree to struggle.
Alternatives to root pruning
Cutting into a tree’s root system is pretty stressful for the plant, so I usually recommend it as a last resort. Instead of reaching for the saw, why not try working with the landscape? You can sow grass, spread a nice layer of bark mulch, or try underplanting with some hardy groundcovers. Here are a few of my favorites that thrive under a maple:
- Barrenwort (Epimedium)
- Periwinkle (Vinca)
- Waldsteinia (Barren Strawberry)
- Foamflower (Tiarella)
If you want to stick with a lawn but are worried about your mower hitting those uneven roots, installing some turf reinforcement grids can be a lifesaver. If you go the mulch route, just clear out any weeds first and lay down a thin layer of humus before spreading your mulch to give the tree a little nutrient boost.
