Skip to content
Grow In Backyard
Landscaping & Hardscaping

Landscaping Under Trees: What Survives Dry Shade

Under a mature tree the problem is root competition and drought, not shade. Plants that cope, how to plant without damaging roots, and what never works.

By Salma 4 min read Save to Pinterest — opens Pinterest in a new tab
A hosta leaf backlit in shade, its ribbed surface and pale margin clearly visible
Photo: MabelAmber, Pixabay Content License, via Pixabay
On this page

The problem under a tree is rarely the shade. It is that the tree takes the water first, from exactly the depth everything else roots in.

Why it is difficult

  1. Root competition. A mature tree’s feeding roots occupy the top 12 to 18 inches across an area wider than the canopy, and they are better at taking water than anything you plant
  2. Rain shadow. A dense canopy sheds rain outward, so the ground near the trunk can be dry even after a wet week
  3. Low light, which rules out most flowering plants but matters less than the first two
  4. Compaction, because the area under a tree is usually walked on

That combination is called dry shade, and the plant list for it is short but reliable.

What to plant

Dry shade performers
PlantTypeNotes
EpimediumGround coverThe outstanding one. Evergreen, spreads steadily
Hardy geranium (macrorrhizum)Ground coverTough, smothers weeds, scented foliage
BergeniaClumpEvergreen, thick leaves, winter colour
HelleboreClumpFlowers in late winter when nothing else does
PulmonariaClumpEarly flowers, spotted foliage
Dryopteris fernsClumpTolerates dry far better than most ferns
Japanese anemoneTallLate flower; can spread enthusiastically
Vinca minorGround coverFast, dense — check it is not invasive locally
Sweet woodruffGround coverSpreads, fragrant
Spring bulbsBulbFlower before the canopy closes

Spring bulbs are the trick worth knowing: snowdrops, aconites, wood anemone and daffodils complete their year before the tree is in full leaf, so the shade never affects them.

Planting without damaging the tree

  1. Clear by hand. No rotavator, no digging over
  2. Feel for roots with a hand trowel before committing to a position
  3. Plant in the gaps. If a spot is solid root, move a foot sideways
  4. Never cut a root thicker than about an inch — those are structural
  5. Small plants, 9 cm pots, which need a far smaller hole than a 2-litre
  6. Backfill with compost in the planting pocket only, not as a layer over everything
  7. Plant in autumn, so roots establish before the first dry summer
  8. Water through two summers. This is the step people skip and the reason plantings fail

Do not raise the soil level over the roots

Adding four inches of topsoil to make a nice level bed is the most common way gardens kill mature trees — and the tree dies three to five years later, so the cause is rarely connected to the effect.

Roots need gas exchange. An inch or two of compost or mulch is fine; a continuous layer of soil is not, and nothing should ever be piled against the trunk.

Mulch, which does most of the work

  • Two to three inches of bark or wood chip over the whole area
  • Six inches clear of the trunk. The mulch volcano piled against bark rots the collar
  • Top up annually at first
  • It conserves the moisture you are competing for, which helps the tree as well as the planting
  • Free arborist chip is ideal here, composted for six months first

If you would rather not plant at all

Entirely reasonable, and often the best-looking answer:

  • A clean mulched circle out to the drip line, edged
  • A bench or a seat under the canopy, on gravel over a membrane-free compacted base
  • Large pots standing on the mulch, planted with whatever you like — no root competition at all, and movable
  • Stepping stones through the mulch to make it a route rather than a dead area

What never works

  • Grass. It will always be thin. Stop fighting it
  • A raised bed built over the roots, which is the soil-burial problem with edges
  • Trenching for irrigation or lighting across the root zone
  • English ivy where it is invasive — it climbs, and the canopy weight is a storm risk
  • Planting large specimens, which need holes that cut roots
  • Skipping the water in the first two summers

Common questions

What can I plant under a tree?

Plants adapted to dry shade, planted small so the roots go in with minimal disturbance. Epimedium, hardy geranium, bergenia, hellebore, pulmonaria, dryopteris ferns, Japanese anemone and spring bulbs all cope with both the dark and the drought. Plant in autumn, water through the first two summers, and accept that the tree wins any competition for water in year one.

Why won't grass grow under my tree?

Two reasons, and shade is the lesser one. The tree takes most of the available water and nutrients from the top layer of soil, which is exactly where grass roots are, and mature canopies cut light below what turf needs. Thinning the canopy helps a little, but the root competition does not go away. A planted bed or a mulched circle is the realistic answer rather than fighting for a lawn that will always look thin.

Can I put soil on top of tree roots?

Not more than an inch or two, and never against the trunk. Tree roots need gas exchange and most of them sit in the top 12 to 18 inches of soil, so adding a depth of topsoil suffocates them — a common cause of mature trees declining years after a garden is landscaped. If you need more depth for planting, use pockets of compost between roots rather than a continuous layer.

What is the best ground cover for under trees?

For dry shade, epimedium is the outstanding one — evergreen, tough, and it spreads steadily without being invasive. Vinca minor, pachysandra, sweet woodruff, ajuga and wild strawberry also cope. Avoid English ivy where it is invasive, because it climbs the tree and the weight is a real problem in a storm. Plant ground cover in autumn and expect two seasons before it closes.

Should I mulch under a tree?

Yes, and it is the single most useful thing you can do. Two to three inches of bark or wood chip over the root zone conserves moisture, moderates soil temperature and suppresses competition. Keep it clear of the trunk by six inches — mulch piled against bark holds moisture against it and rots the collar, which is what the volcano of mulch around suburban trees is doing.

Is it safe to dig under a tree?

Small holes between roots, yes. Cutting roots thicker than about an inch, no — those are structural and the tree may become unstable or decline. Never trench across the root zone, never use a rotavator, and work outward from the trunk feeling for roots with a hand trowel. If a spot is solid root, move the plant a foot sideways rather than cutting through.

Backyard Weekly

Know what to plant, week by week

Join the weekly email for seasonal jobs, fixes for what is going wrong, and gear worth buying.

Not ready to subscribe? The planting calendar is free and needs no email.

By subscribing you agree to our privacy policy. Grow In Backyard will never sell your address.

Keep reading