Planting under trees can make a yard look lush and layered, but it’s not as simple as putting new plants into the soil. Trees have a sensitive area called the root flare, where the trunk meets the soil surface, and protecting this part is essential for keeping the tree healthy. Many homeowners unknowingly bury or disturb the root flare while planting shrubs, flowers, or decorative plants underneath mature trees, causing long-term damage.

Before you begin planting anything under your trees, it’s important to understand how the root flare works, why it matters, and how to avoid harming the tree. And if your yard has overgrown or unsafe trees that may interfere with new planting, services like Pasco County tree removal can help clear out unwanted or hazardous trees safely.

Let’s take a closer look at what you need to know before you dig.

What Is the Root Flare?

Its an area at the bottom of a tree where the trunk broadens and the roots begin to spread out horizontally. It’s the natural transition between trunk and root system, and keeping this area exposed to air is crucial. When it stay buried under soil or mulch, the tree can’t “breathe” properly, leading to rot, stress, and weakened structural stability.

The problem is that homeowners often cover the flare accidentally while planting decorative plants or adding fresh layers of mulch. Even a few extra inches of soil can cause long-term issues.

Why Root Flare Protection Matters

There are a few key reasons why keeping the root flare exposed is essential for the health of the tree:

It prevents moisture-related rot.

When the root flare stays buried, moisture gets trapped against the trunk. Over time, the bark begins to rot, inviting insects and fungi that weaken the tree.

It supports stronger stability.

A visible and healthy root flare helps trees anchor themselves properly. Buried flares often lead to weaker root systems, making the tree more prone to leaning or falling.

It improves air exchange.

Tree roots need oxygen. Covering the root flare reduces oxygen flow to the upper root system, causing stress and slowing growth.

It reduces pest and disease risks.

A buried flare becomes a magnet for pests like ants, beetles, borers and  risk of fungal infections.

All of these factors highlight why protecting the root flare is a key part of tree care—especially when planting around mature trees.

Can You Plant Under Your Trees? Yes, But With Care

Planting flowers or ground cover under a tree can look beautiful and help fill empty spaces in your yard. The key is doing it in a way that doesn’t disturb the root flare or damage the tree’s health.

Here’s how to plant safely:

Choose shallow-rooted plants

Plants that grow close to the soil surface are ideal for planting under trees. This way, you avoid digging too deeply and disturbing major tree roots. Ferns, hostas, impatiens, and certain ground covers can thrive in shaded areas without competing aggressively with the tree.

Avoid heavy digging

Tree roots grow wide and shallow. Even small holes can cut important roots that help support the tree. Try to disturb the soil as little as possible and avoid using large tools that dig deep into the ground.

Keep soil levels the same

Never add extra soil around the base of the tree. Even a thin layer can bury the flare and block air flow. If your planting design calls for raised soil, keep it away from the tree’s trunk area entirely.

Use mulch lightly and correctly

Mulch helps in locking the moisture in the soil, but too much mulch damages trees. Keep mulch 6–8 inches away from the trunk and use a thin 2–3 inch layer. Avoid the “mulch volcano” look that many people mistakenly use.

Water deeply, not constantly

Trees already have established roots and don’t need frequent watering. Water new plants separately and avoid overwatering the base of the tree, as excess moisture harms the root flare.

Common Mistakes to Avoid When Planting Under Trees

Even well-intentioned planting can cause problems when the root flare isn’t protected. Here are the mistakes homeowners make most often:

Planting too close to the trunk

This smothers the root flare and causes constant moisture buildup.

Adding too much soil or compost

This buries essential roots and encourages rot.

Getting aggressive with digging tools

Accidentally cutting or damaging major roots can permanently weaken the tree.

Planting large shrubs or trees underneath

Big plants compete for nutrients and often require deep planting holes—both of which harm the existing tree.

Ignoring signs of stress

Yellow leaves, early leaf drop, fungus, or cracked bark can all indicate root flare problems.

By avoiding these mistakes, you help both your tree and your new plants thrive peacefully together.

When to Bring in a Professional

Even with proper care, some trees may already have buried root flares or existing damage. In these cases, professional help is the safest and most effective option. Arborists can expose the root flare safely, reshape the base, check for root rot, and recommend treatments.

If your yard has damaged, leaning, or hazardous trees that make planting difficult, your local tree care experts can guide you on whether you can save the tree. They can also help you plan planting layouts that protect the health of both trees and plants.

Working with professionals ensures your landscape grows in a balanced, healthy, and eye-catching way.

Setting Up Your Landscape for Success

Planting under trees doesn’t have to be complicated. A little understanding of the root flare, thoughtful planning, and careful planting can make your landscape look beautiful without harming your mature trees. By choosing shallow-rooted plants, avoiding soil buildup, and keeping mulch away from the trunk, you’re already setting yourself up for long-term success.

Whether you’re refreshing your garden or preparing your yard for new plantings, protecting the root flare keeps your trees strong, stable, and healthy. With the right approach—and expert guidance when needed—you can create a landscape that thrives naturally and looks great through every season.