What To Plant Around Pennsylvania Foundation Trees

Planting around foundation trees in Pennsylvania requires balancing structural safety, tree health, and landscape aesthetics. Many homeowners want to create attractive beds beneath or around the drip line of mature trees that sit close to house foundations. Done well, foundation plantings enhance curb appeal, suppress weeds, and reduce soil erosion. Done poorly, they invite root competition, moisture problems for the building, pest harborage, and stressed trees. This guide covers climate and soil context, practical plant recommendations for common site conditions in Pennsylvania, spacing and installation standards, maintenance practices, and specific takeaways you can use when planning or renovating foundation plantings.

Pennsylvania climate and site context

Pennsylvania spans USDA hardiness zones roughly from 5a in the higher elevations to 7a in the southeast. That means winters can be cold, summers humid, soils vary from sandy to clay, and deer pressure is a regular concern in many areas. Typical issues around foundations include:

compacted soils from construction;
altered drainage and grade against the foundation;
salt exposure from winter deicing on nearby driveways and walkways;
shade and root competition under established trees;
occasional drought stress in summer if trees dominate moisture.

Understanding the specific microclimate at your house – sun exposure, prevailing wind, soil texture, and drainage – will determine which plants will thrive near foundation trees.

Principles for planting near foundations and trees

Plant selection should follow a few basic rules to protect both the building and the trees:

Maintain a minimum clearance from the foundation so that plants do not trap moisture against siding or block airflow. A general rule is to leave at least 2 to 3 feet of clear wall space for maintenance and airflow; larger shrubs should be placed at least 4 to 6 feet from the foundation depending on mature size.
Avoid planting large, deep-rooted shrubs within the tree root zone where they will compete for water and nutrients. For medium and large trees, keep woody large shrubs and small trees outside the dripline when possible.
Use shallow-rooted, low-profile groundcovers and perennials beneath tree canopies. These coexist better with tree roots and reduce need for deep cultivation.
Keep mulch depth shallow around tree roots and trunks. Maintain 2 to 3 inches of mulch and keep mulch pulled back 4 to 6 inches from tree trunks and foundation walls to prevent rot and rodent shelter.
Preserve soil grade and drainage. Do not add soil against the foundation or the tree trunk. Regrading can suffocate roots and lead to foundation moisture problems.
Consider deer and salt. Choose deer-resistant plants in high-deer areas and salt-tolerant species where deicing salt may reach beds.

Design approach: layering and seasonal interest

A good foundation planting uses layered heights to create depth and balance with the house and tree canopy. Think in three strata:

low groundcovers and perennials in the front (6 to 18 inches),
mid-height shrubs and perennials in the middle (2 to 4 feet),
taller background shrubs or small specimen trees at the back where they will not contact the house (4 to 8 feet or more, placed farther from the foundation).

Mix evergreen anchors for winter structure with deciduous shrubs and perennials for seasonal color. Use repeating plant groups for cohesion and mix textures and foliage color for interest.

Recommended plants by site condition

Below are practical plant lists adapted to common Pennsylvania foundation situations. All plants listed are widely available and appropriate for many parts of the state, but check your exact hardiness zone and soil pH.

Shade under tree canopy (dry to average moisture)

Hostas – many cultivars from small to large; give foliage variety and excellent shade performance.
Ferns – ostrich fern, lady fern, and Christmas fern for texture and native suitability.
Heuchera (coral bells) – for foliage color and low profile.
Brunnera macrophylla – blue-flowering spring interest and heart-shaped leaves.
Pulmonaria (lungwort) – early spring flowers, good for dappled shade.
Lamium or Ajuga – groundcovers to suppress weeds; avoid aggressive cultivars where they spread into natural areas.

Part to full sun, well-drained soils near foundation edge

Lavender and Russian sage – for fragrant, drought-tolerant summer color.
Salvia and Nepeta (catmint) – long bloom periods and low water needs.
Sedum and Sempervivum – very low-growing succulents for hot, sunny beds.
Ornamental grasses (low Carex species, Pennisetum ‘Hameln’) – for form and movement.

Moist or rain garden sites near foundations with poor drainage

Iris versicolor (blue flag iris) – for seasonal wet pockets.
Switchgrass (Panicum virgatum) – native grass tolerant of varying moisture.
Joe-Pye weed and cardinal flower – tall perennials for wetter, sunny sites (place farther from house).
Spirea ‘Little Princess’ – compact and tolerant of moist soils.

Deer-prone yards

Boxwood – evergreen, generally acceptable to deer in many areas, but check local browsing pressure.
Inkberry holly (Ilex glabra) – evergreen native holly that holds up well to deer and wet soils.
Viburnum species – many viburnums are less preferred by deer and offer seasonal interest.
Ferns – typically avoided by deer for large dense displays.

Salt-exposed or driveway-adjacent plantings

Junipers (low-growing cultivars) – tough and salt-tolerant.
Red osier dogwood – tolerates salt spray better than many shrubs.
Rugosa roses – tolerates salt, disease-resistant, good for informal hedges.

Plants to avoid directly against foundations or tree trunks

Large shrubs and small trees that will reach over 4 to 6 feet at maturity if placed within 4 feet of the foundation.
Woody plants with invasive root systems that could impact foundation drains or sidewalks.
Vinca minor in some regions – can become invasive and smother native groundcover; consider native alternatives.
Too many high-water-demand plantings under trees – they will compete with the tree and require more irrigation.

Installation steps (practical checklist)

Locate utilities and determine exact clearance from foundation and tree trunk before digging.
Improve soil structure only if necessary and avoid large-scale soil changes near tree trunks. If adding topsoil, do so outside the critical root zone and keep build-up minimal.
Place larger shrubs at least 4 to 6 feet from the foundation and beyond the most active tree roots when possible.
Use a 2 to 3 inch organic mulch layer, keeping mulch away from the base of the foundation and trunk by several inches.
Plant shallow-rooted groundcovers and perennials within the tree dripline; avoid deep rototilling in root zones.
Install a drip irrigation or soaker system if supplemental water will be needed; water deeply but infrequently to encourage deeper roots.
Monitor plant and tree health seasonally and adjust irrigation and pruning to reduce pest and disease risks.

Maintenance considerations

Prune shrubs to maintain a 2 to 3 foot air gap from the house siding and to prevent branches from touching the foundation or walls.
Check mulch annually and maintain at the recommended depth. Pull mulch away from trunks.
Inspect grading annually and ensure water flows away from the foundation. Correct any pooling promptly.
Avoid over-fertilizing plants near trees; excessive nitrogen can shift competition and damage tree roots over time.
Watch for root suckers, girdling roots, or signs of tree stress (dieback, early leaf drop). If you suspect root damage from planting work, consult a certified arborist.

Design examples and combinations

Example 1 – Shaded foundation bed beneath mature oak:

Front: Heuchera ‘Palace Purple’ and small clumps of Ajuga.
Middle: Variegated hosta and brunnera.
Back: Low evergreen inkberry spaced 4 to 6 feet from foundation as an anchor.

Example 2 – Sunny edge near driveway:

Front: Sedum ‘Autumn Joy’ and low catmint.
Middle: Lavender and coreopsis.
Back: Ornamental grass (Panicum) as a soft backdrop set at least 3 to 4 feet from the foundation wall.

Final practical takeaways

Prioritize tree health and foundation safety: do not sacrifice one for the other.
Choose low-profile, shallow-rooted plants under trees; reserve larger shrubs for the outer edge of planting beds.
Keep plantings at least 2 to 3 feet from the foundation for airflow and maintenance; larger shrubs should be positioned farther away.
Mulch correctly and maintain grading to prevent moisture problems against the house and tree stress.
Match plant choice to light, moisture, deer pressure, and salt exposure for long-term success.
When in doubt with mature trees or complex drainage issues, consult an arborist or landscape professional.

With thoughtful selection and placement, you can create attractive, low-maintenance foundation plantings that complement Pennsylvania homes and protect the health of foundation trees for years to come.