How Nearby Trees Affect Shrubs More Than You Realize

You can plant a healthy shrub, prepare the soil, water it regularly, and still watch it struggle. When that happens, it is easy to blame the shrub, the weather, or Georgia’s red clay.

But sometimes the real problem is the mature tree growing nearby.

Large trees affect much more than the amount of shade in a landscape. Their roots compete with shrubs for water, nutrients, oxygen, and growing space. Their canopies can also redirect rainfall, change sunlight levels, and create surprisingly dry soil underneath.

At Bobby & Lynn’s Plant Farm, one thing we have noticed is that soil near mature trees can remain dry even after a good rain. The surrounding yard may feel moist, while the soil beneath the tree canopy is still dry several inches below the surface.

Understanding this hidden competition can help homeowners choose better planting locations and avoid years of frustration.

Tree Roots Extend Far Beyond the Trunk

Most homeowners know that trees have large root systems, but many underestimate how far those roots spread.

Tree roots commonly extend beyond the outer edge of the branches. They do not remain in a small circle around the trunk, and many of the roots that absorb water and nutrients grow relatively close to the soil surface.

That puts them in direct competition with shrub roots.

When digging near a mature tree, you may find:

• A planting hole filled with small feeder roots
• Thick roots running close to the surface
• Hard, compacted soil between the roots
• Very little open soil for a new shrub to establish

Even when there appears to be enough physical space between the tree and shrub, the underground growing space may already be crowded.

Trees Can Leave the Soil Dry After Rain

One of the most surprising effects of a mature tree is how dry the soil underneath it can remain.

We have seen this ourselves at the plant farm. After a noticeable rainfall, soil in an open area may be moist while soil near a large tree remains much drier than expected.

There are two main reasons for this.

First, the tree canopy intercepts some of the rainfall. Water lands on leaves and branches, where some of it evaporates or runs toward a different part of the yard.

Second, the tree’s extensive root system quickly absorbs much of the water that does reach the ground.

This can create what gardeners sometimes describe as dry shade: an area that receives limited sunlight but is also much drier than a typical shady location.

A shrub planted there may wilt even though it recently rained.

Trees and Shrubs Compete for Water

A mature tree already has an established root system and a major advantage over a newly planted shrub.

During hot or dry weather, the tree can pull moisture from a wide area. The shrub, meanwhile, may have only a small root system extending slightly beyond its original nursery container.

Signs that a shrub may be losing the competition for water include:

• Wilting that returns quickly after watering
• Brown or crispy leaf edges
• Slower-than-expected growth
• Smaller leaves or flowers
• Early leaf drop
• Dieback on individual branches

However, do not assume every wilting shrub needs more water.

Georgia clay can remain wet in one location while nearby soil beneath a tree stays dry. Always check the soil before watering rather than relying only on how the surface looks.

Push a finger, hand trowel, or soil probe several inches into the ground near the shrub. If the soil feels dry at root level, watering may be needed. If it still feels cool and moist, give it more time.

The University of Georgia Extension also notes that shrubs growing near large trees may require more supplemental water because of extensive root competition.

Trees Also Compete for Nutrients

Water is not the only resource being shared.

Tree roots also absorb nutrients from the same upper layer of soil where shrub roots are trying to grow. Fertilizer applied near a struggling shrub may be absorbed partly by the nearby tree.

This is one reason fertilizer does not always solve poor growth beneath trees.

A shrub that lacks sunlight, moisture, or root space will not suddenly thrive because fertilizer was added. In some cases, fertilizing an already stressed shrub can make the problem worse by encouraging new growth that the plant cannot support.

Before fertilizing, first evaluate:

• Soil moisture
• Drainage
• Sunlight
• Planting depth
• Root competition
• The shrub’s natural growing requirements

Shade Changes as Trees Grow

A planting location does not stay exactly the same from year to year.

A young tree may cast only light shade when a shrub is first planted. As the tree grows, its canopy becomes wider and denser. A shrub that once received several hours of sunlight may eventually receive very little.

Seasonal changes matter too.

A location that appears sunny in early spring may become heavily shaded after the tree fully leafs out. This is especially important when choosing flowering shrubs, because reduced sunlight can lead to fewer blooms.

Before planting, observe the location:

• In the morning
• Around midday
• In late afternoon
• During spring
• After trees have fully leafed out in summer

A few hours of observation can prevent planting a sun-loving shrub where it will eventually receive mostly shade.

Some Trees Create More Competition Than Others

All mature trees affect nearby plants, but some create more challenging conditions.

Trees with dense canopies or widespread surface roots may create especially strong competition. Common examples include:

• Maples
• Sweetgums
• Oaks
• Pines
• River birches
• Willows
• Poplars

Conditions can also vary by individual tree, soil type, tree age, slope, irrigation, and distance from the trunk.

Rather than choosing shrubs based only on the tree species, examine the actual planting site. Look at the amount of visible surface roots, soil moisture, sunlight, and available planting space.

Falling Leaves, Pine Needles, and Debris Add Up

Nearby trees also affect shrubs from above.

Leaves, pine needles, seed pods, small branches, and other debris can accumulate around or on top of shrubs.

A light layer of leaves can act as natural mulch, but a thick layer may:

• Smother small plants
• Cover the shrub’s crown
• Hold moisture against stems
• Reduce air circulation
• Hide pest activity
• Block water from reaching the soil evenly

Pine needles can be useful as mulch, but they should not be allowed to pile deeply against the base of a shrub.

Keep the crown and main stems visible, and remove excessive buildup when necessary.

Do Not Add Deep Soil Over Tree Roots

When homeowners encounter exposed roots or poor soil beneath a tree, they sometimes try to solve the problem by adding a thick layer of topsoil.

This can harm the tree.

Tree roots need oxygen, and burying them beneath several inches of new soil can reduce airflow and alter drainage. Piling soil or mulch against the tree trunk can also encourage decay.

Avoid:

• Building a deep raised bed around the trunk
• Covering major roots with a thick layer of soil
• Piling mulch against the bark
• Changing the soil level dramatically beneath the canopy

A light layer of mulch is usually safer than adding deep soil, but it should remain several inches away from the tree trunk.

Avoid Cutting Large Tree Roots

It can be tempting to cut through tree roots to make room for a shrub, but damaging major roots may weaken or destabilize the tree.

Large roots can be important for both water uptake and structural support.

When digging, move the planting location if you encounter major roots. Do not force a large planting hole into a root-filled area simply because it looks like the perfect location above ground.

Sometimes moving the shrub a few feet farther away makes a significant difference.

Shrubs That May Handle Filtered Shade

Some shrubs are better suited to filtered light and partial shade than others. Possible choices for Georgia landscapes include:

• Oakleaf hydrangea
• Virginia sweetspire
• Aucuba
• Camellia
• Mahonia
• Fothergilla
• Certain azaleas
• Summersweet

However, shade tolerance does not automatically mean root-competition tolerance.

Even a shade-loving shrub can struggle if the soil is extremely dry or filled with tree roots. Plant selection helps, but it cannot completely overcome a poor planting site.

Shrubs That May Struggle Near Mature Trees

Shrubs that require abundant sunlight, consistent moisture, or rich open soil may perform poorly beneath dense tree canopies.

These can include:

• Sun-loving panicle hydrangeas
• Butterfly bushes
• Many roses
• Crape myrtles
• Heavy-blooming full-sun shrubs
• Plants that require consistently moist soil

The plant may survive, but it may grow slowly, bloom poorly, or require constant attention.

A plant that merely survives is not necessarily planted in the right location.

Tips for Planting Shrubs Near Trees

When planting near mature trees is unavoidable, these steps can improve the shrub’s chances:

Choose a Smaller Shrub

A smaller nursery plant requires a smaller planting hole and may establish more easily between existing tree roots.

Plant Farther From the Trunk

Conditions often improve as you move away from the trunk and the densest concentration of major roots.

Check Moisture Before Watering

Do not assume rainfall reached the shrub’s roots. Check the soil several inches deep.

Water Slowly and Deeply

Apply water directly over the shrub’s root zone and allow it to soak in gradually. Avoid frequent shallow sprinkling.

Use Mulch Carefully

Apply approximately two to three inches of mulch around the shrub, but keep it away from the shrub’s stems and the tree trunk.

Select Plants for the Actual Conditions

Choose plants based on the site’s true sunlight, moisture, and available root space—not simply whether the label says “part shade.”

Expect Slower Growth

A shrub growing near a mature tree may establish and grow more slowly than the same shrub planted in an open bed.

When Moving the Shrub Is the Best Choice

Sometimes no amount of watering, fertilizing, or pruning will overcome severe tree competition.

Consider relocating the shrub if:

• It repeatedly wilts
• It produces little new growth
• Flowering continues to decline
• The planting area is packed with tree roots
• The site has become much shadier
• The shrub requires constant watering to survive

Moving the shrub to a location with more open soil, dependable moisture, and appropriate sunlight may be easier than continuing to fight the conditions beneath a mature tree.

Final Thoughts

Trees add shade, beauty, wildlife habitat, and value to a landscape, but they also change the growing conditions around them.

Their roots compete for water and nutrients. Their canopies alter sunlight and redirect rainfall. As they grow, a location that once worked well for a shrub may become increasingly difficult.

Our own experience has shown us that soil near a mature tree can remain surprisingly dry even after rain. That is why it is important to check the soil itself instead of assuming every part of the yard received the same amount of moisture.

Before blaming a struggling shrub, look up at the canopy and down at the soil.

The tree growing nearby may be affecting the shrub far more than you realize.

Frequently Asked Questions

Why is the soil dry under my tree after it rains?

The tree canopy may intercept part of the rainfall, while the established root system quickly absorbs much of the water that reaches the ground.

Should I water shrubs after it rains?

Check the soil several inches deep before watering. Soil beneath a tree may remain dry after rain, but other areas—especially Georgia clay—may still be wet.

Can I plant hydrangeas beneath mature trees?

Some hydrangeas, particularly oakleaf hydrangeas, can tolerate filtered shade. However, they may still struggle with severe root competition and dry soil.

Will fertilizer help a shrub growing near a tree?

Not if the main problems are inadequate sunlight, dry soil, or limited root space. The tree may also absorb part of the fertilizer.

Can I cut tree roots to make room for a shrub?

Avoid cutting large roots. This can stress the tree and may affect its stability. Moving the planting location is usually safer.

How far should a shrub be planted from a tree?

There is no single distance that works for every tree. Plant as far from the trunk and major surface roots as the landscape allows, and inspect the soil before digging.

Suggested Internal Links

• Seven Places Around Your House Where Plants Struggle
• Is Your Georgia Clay Soil Still Too Wet? Here’s How to Tell
• Hydrangea Help
• Before You Buy Another Plant