Pennsylvania has one of the largest white-tailed deer populations in the US and one of the most serious deer browse problems in northeastern horticulture. Per Penn State Extension, the white-tailed deer density in some suburban and rural Pennsylvania counties exceeds 50 deer per square mile — a level at which even normally deer-resistant plants begin to show browse damage.
The problem is particularly acute in counties where development has reduced hunting access while increasing food sources (residential plantings, mast crops, agriculture). Centre, Chester, Montgomery, Lancaster, and York counties consistently report the highest deer-plant conflict levels.
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Most Reliable Deer-Resistant Plants for Pennsylvania
Per Penn State Extension, the following plants have demonstrated consistent resistance to deer browse in Pennsylvania field trials:
Bulbs
Narcissus (Daffodil) — Per Penn State, all narcissus species are reliably deer-resistant due to toxic lycorine alkaloids. Replace tulips with daffodils in open beds. On Long Island, I grow daffodils under moderate-to-heavy deer pressure and have never lost a single bulb to browsing.
Ornamental Allium — Per Penn State, ornamental alliums (Allium hollandicum, A. 'Globemaster', A. aflatunense) are reliably avoided due to allicin compounds. Plant in fall at 6-inch depth; deer ignore them even when massing in adjacent beds.
Camassia (Camassia leichtlinii, C. quamash) — Per Penn State, native camassia bulbs are reliably deer-resistant and produce blue flower spikes 18—24 inches tall in May. An underused alternative to deer-vulnerable tulips.
Keep deer and rabbits out
Liquid Fence uses egg-and-garlic scent. One application lasts 30 days and works on both deer and rabbits. Read our full pick.
Perennials
Per Penn State Extension, the most consistently deer-resistant perennials in Pennsylvania:
- Catmint (Nepeta × faassenii) — strongly aromatic, consistently avoided; 'Walker's Low' is the standard landscape cultivar, growing 24—36 inches
- Russian sage (Perovskia atriplicifolia) — aromatic, rating: rarely damaged; effective in zones 4—9
- Yarrow (Achillea millefolium) — aromatic, toxic in large amounts
- Coneflower (Echinacea purpurea) — seldom severely damaged
- Black-eyed Susan (Rudbeckia fulgida) — seldom severely damaged
- Switchgrass (Panicum virgatum) — rarely browsed; grasses are generally low-preference
- Blue wild indigo (Baptisia australis) — seldom severely damaged; toxic; also a nitrogen fixer
- Bleeding heart (Lamprocapnos spectabilis) — rarely damaged; toxic alkaloids
- Ferns — most fern species are rarely browsed; Christmas fern (Polystichum acrostichoides) and cinnamon fern (Osmundastrum cinnamomeum) are good evergreen and deciduous choices respectively
Shrubs
Per Penn State Extension, the most deer-resistant shrubs for Pennsylvania:
- Boxwood (Buxus sempervirens, B. microphylla) — rarely damaged; toxic alkaloids; requires winter protection from desiccation in zone 5
- American holly (Ilex opaca) — rarely damaged; use instead of arborvitae for screens; tolerates shade and wet soils
- Inkberry holly (Ilex glabra) — rarely damaged; native; tolerates poorly drained sites
- Mountain laurel (Kalmia latifolia) — rarely damaged; contains grayanotoxins; Pennsylvania's state flower
- Yew (Taxus spp.) — rarely damaged when established; toxic taxine alkaloids; note: the fleshy red aril (seed covering) is consumed by birds with no apparent harm, but foliage and seeds are toxic to mammals
- Bayberry (Morella pensylvanica) — seldom severely damaged; native; nitrogen-fixing; great for sandy, acidic sites
- Virginia sweetspire (Itea virginica) — seldom severely damaged; outstanding fall color
Plants Frequently Destroyed by Deer in Pennsylvania
Per Penn State Extension, do not plant these in unfenced areas in Pennsylvania:
| Plant | Comment |
|---|---|
| Arborvitae (Thuja occidentalis) | Catastrophically browsed; stripped to bare stems |
| Hostas (Hosta spp.) | Eaten completely; stems bitten off |
| Tulips (Tulipa spp.) | Eaten before bloom in most counties |
| Garden phlox (Phlox paniculata) | Frequently browsed |
| Roses (Rosa spp.) | Heavily browsed; especially new growth and canes |
| Rhododendron | Heavily browsed in winter |
| Impatiens | Consumed readily |
| Burning bush (Euonymus alatus) | Frequently browsed; also invasive in much of PA |
Protection Methods
Fencing
Per Penn State Extension, an 8-foot woven wire fence is the most reliable exclusion method. Electric fence options include a single-strand baited (peanut butter or apple) fence or a two-fence system with an inner and outer line 3 feet apart. Per Penn State, deer will not jump two fences simultaneously.
Repellents
Per Penn State Extension, repellents containing putrescent egg solids (Plantskydd deer repellent) or capsaicin (Deer Out, Deer-Off) are the most effective commercial options. All must be reapplied every 2–4 weeks and after rain. They are most effective when applied before deer establish a browsing habit at a new location.
Repellent rotation: Per Penn State, deer adapt to a single repellent type over time. Rotating between different repellents (egg-based, then capsaicin-based, then botanical oils) maintains effectiveness longer than using one product continuously.
Individual Plant Protection
Per Penn State Extension, tree tubes and spiral plastic guards protect young woody plants until they are large enough to sustain browse damage. Wire cylinders (30-inch diameter, 4-foot tall) protect established perennial clumps.
Common Mistakes in Deer-Resistant Planting
| Mistake | Consequence | Correct approach |
|---|---|---|
| Planting arborvitae as a screen | Stripped to bare wood within 2—3 winters | Substitute American holly (Ilex opaca) or inkberry for evergreen screening |
| Relying on one repellent all season | Deer adapt; effectiveness drops by week 6 | Rotate between egg-based (Plantskydd deer repellent) and capsaicin-based (Deer Out) products |
| Treating deer-resistance as binary | A "rarely damaged" plant at low deer density may be browsed heavily at 50+ deer/mi² | Use the Rutgers NJAES scale in combination with local county deer pressure data |
| Not protecting new plantings of "resistant" species | Even resistant plants are vulnerable when young and tender | Protect any new planting for its first two growing seasons |
Frequently Asked Questions
Is arborvitae truly the most deer-damaged plant in Pennsylvania? Per Penn State Extension, arborvitae (Thuja occidentalis) consistently receives the most deer browse complaints in Pennsylvania — partially because it is one of the most widely planted evergreens. Deer strip the lower branches down to bare wood, effectively destroying the plant's appearance permanently. Per Penn State, American holly is a direct substitution for screening in deer country.
Do motion-activated sprinklers work in Pennsylvania? Per Penn State Extension, motion-activated water sprinklers (ScareCrow, Orbit) provide deterrence but require maintenance, a water supply, and deer learn to avoid activation times. They are most useful in small areas around specific high-value plantings rather than as perimeter exclusion devices.
What can I plant under a deer fence to extend the deer-resistance zone? Per Penn State Extension, deer can reach under a fence to browse plants within 18 inches of the fence line. Plant smaller deer-resistant perennials (catmint, daffodils, ferns) in this zone rather than preferred species that would be vulnerable.
Recommended gear: Best deer repellent: Liquid Fence vs Bobbex vs Plantskydd — our buying guide, with picks weighed against university Extension guidance and product labels.
Sources
- Penn State Extension — Deer-Resistant Plants
- Penn State Extension — Deer Management
- Rutgers NJAES — Landscape Plants Rated by Deer Resistance