Pennsylvania Gardening Guide: Best Plants for Zones 5 to 7

Pennsylvania spans more than 300 miles west to east, from the Lake Erie shoreline to the Delaware River — and that distance brings three distinct USDA hardiness zones compressed into a single state. Zone 5 covers the Pocono Mountains and the northern highlands, where Erie and State College gardeners work with last frost dates pushing well into May. Zone 6 stretches across the central counties and metro Pittsburgh. Zone 7a reaches the Philadelphia suburbs and the Delaware Valley, where gardeners can grow plants that would not survive a central Pennsylvania winter.

That range means there is no single Pennsylvania gardening calendar. The right planting window for tomatoes in Philadelphia is three to four weeks earlier than the same decision in Pittsburgh — and nearly five weeks ahead of Erie. Understanding your specific zone, not just the state average, is the foundation of every planting decision this guide covers.

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What Pennsylvania gardeners share, regardless of zone, is a common set of challenges: significant deer pressure across most of the state, variable soil quality from the clay-heavy Piedmont to the thin rocky profiles of the Appalachian ridges, and weather systems that deliver cold snaps well past average last frost dates. This guide addresses all three, with frost data for eight Pennsylvania cities, zone-calibrated variety picks, and a deer-resistant plant list built around what actually works here.

Understanding Pennsylvania’s USDA Hardiness Zones

The 2023 USDA Plant Hardiness Zone Map update shifted roughly half the country warmer by half a zone, and Pennsylvania was included. If you have not checked your zone since before 2023, it may have changed. The current map places Pennsylvania in zones 5a through 7a.

• Zone 5 (5a/5b): Northern Pennsylvania — including the Pocono Plateau, portions of Sullivan, Bradford, Tioga, and Cameron counties, and the Lake Erie coastal plain near Erie. Average annual extreme minimum temperatures of -20°F to -10°F. Growing season: 140–165 days.
• Zone 6 (6a/6b): The majority of Pennsylvania — Pittsburgh, Harrisburg, Allentown, Scranton, and State College all fall in Zone 6. Average annual extreme minimum of -10°F to 0°F. Growing season: 165–195 days.
• Zone 7a: Southeastern Pennsylvania, including Philadelphia, Chester County, Montgomery County, and the Delaware Valley corridor. Average annual extreme minimum of 0°F to 5°F. Growing season: 200–230 days.

The frost dates below are based on 30-year averages. Use them as your planning baseline, but always factor in local microclimates: south-facing slopes, urban heat islands in Philadelphia, and frost pockets in Appalachian valleys can shift effective dates by one to two weeks in either direction. Penn State Extension maintains Pennsylvania-specific planting data through the Penn State Extension home gardening hub, which is updated regularly and is the most authoritative state-specific resource available.

One practical note on Erie: Lake Erie’s thermal mass creates a lake-effect microclimate that keeps spring temperatures cooler for longer than the zone number might suggest. Erie gardeners should use May 15 as their warm-season planting benchmark regardless of the average last frost date, since cold lake air frequently delays soil warming well past the calendar average.

Spring Vegetables for Pennsylvania Gardens

Pennsylvania’s cool, wet springs are well-suited to a wide range of vegetables — but the practical window varies significantly by zone. Philadelphia-area gardeners can direct sow beans from late April; Erie and State College gardeners need to wait until late May to avoid frost damage to warm-season crops.

Cool-Season Crops: All Zones

Cool-season crops thrive in Pennsylvania’s long springs and are the most universally productive vegetables in the state. They go in the ground 4–6 weeks before your last frost date:

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• Peas: Direct sow when soil temperature reaches 45°F — mid-March in Zone 7a, early April in Zone 6, late April in Zone 5. Choose wrinkled-seed types like ‘Sugar Snap’ or ‘Lincoln’ rather than smooth-seeded varieties for better germination in cool soil.
• Lettuce and spinach: Both tolerate light frost. Succession-plant every two weeks for a continuous harvest into June, then again in late August for fall crops. Pennsylvania’s fall extension is one of the best times of year for leafy greens.
• Broccoli and cabbage: Start indoors 6–8 weeks before last frost. Set out transplants 3–4 weeks before last frost — they handle a light freeze without damage. In Zone 7a, fall crops of broccoli planted in August are often more productive than spring plantings.
• Kale: One of the most forgiving cold-weather crops in the state. In Zone 6 and 7, fall-planted kale left in the garden frequently overwinters and resumes growth in March, making it nearly a year-round crop with minimal effort.

Warm-Season Crops: Zone-by-Zone Windows

Warm-season vegetables — tomatoes, peppers, zucchini, corn, and beans — need both air temperatures above 50°F overnight and soil temperature above 60°F. Do not let the last frost date alone trigger warm-season planting. Soil temperature is the real signal, and in Zone 5 Pennsylvania, soil can take two to three weeks past the last frost date to reach 60°F.

For tomatoes, Penn State Extension’s vegetable gardening guide is clear: transplants set out in cold soil develop phosphorus deficiency symptoms (purple-tinged leaves) because roots cannot absorb phosphorus efficiently below 55°F. Plants put in at the correct soil temperature often catch up to and surpass early-planted ones within two weeks.

Zone 5 gardeners have a 163–165 day window — enough for full-sized tomatoes, but only from transplants started indoors 6–8 weeks ahead. Varieties with 65–72 day maturity (Celebrity, Early Girl, Jetstar) consistently outperform longer-season types in northern Pennsylvania. In Zone 7a, Philadelphia-area gardeners have enough growing season for 85–90 day paste varieties like ‘Amish Paste’ started from transplants.

Timing your vegetable garden across the season is covered in our year-round seasonal planting guide, which includes soil temperature triggers alongside calendar dates for all three Pennsylvania zones.

Best Perennials for Pennsylvania

Pennsylvania’s native plant community is exceptionally rich. The state sits at the crossroads of several ecological zones, and many of the most reliable garden perennials are natives adapted to precisely the rainfall patterns, soil chemistry, and seasonal temperature swings Pennsylvania gardens typically produce.

Top Native Perennials

• Black-eyed Susan (Rudbeckia hirta): Blooms July–September across all three zones. Thrives in full sun, tolerates both clay and sandy soils, and self-sows prolifically. Excellent as a cut flower and highly attractive to native bees. Hardy zones 3–9 — no protection needed anywhere in Pennsylvania.
• Purple Coneflower (Echinacea purpurea): Among the most widely planted native perennials in the state. Drought-tolerant once established, producing flowers July–September followed by seed heads that goldfinches actively feed on through winter. Leave seed heads standing for wildlife value — they add structure to the winter garden as well.
• Wild Blue Indigo (Baptisia australis): A native Pennsylvania wildflower that takes two to three years to reach full flowering size but then requires essentially no care for decades. Deep taproot makes it both drought-tolerant and wind-resistant. Blue pea-like flowers in May–June. Hardy to Zone 3 — a permanent investment for any Pennsylvania garden.
• Joe-Pye Weed (Eutrochium purpureum): Reaches 5–7 feet in Zones 6 and 7, somewhat smaller in Zone 5. Blooms August–September when little else in the garden is at peak. Outstanding butterfly plant — monarch and swallowtail populations use it heavily. Best in moist spots with partial sun; excellent alongside rain gardens or in low areas where other perennials struggle.
• Eastern Columbine (Aquilegia canadensis): A delicate early-blooming native (April–June) that seeds freely and naturalizes in dappled shade. One of the best companions for hostas — it blooms while hostas are still emerging, then dies back as hostas expand to fill the space.

Hostas in Pennsylvania

Hostas are among the most widely planted perennials in Pennsylvania, and the state’s abundant deciduous tree canopy creates ideal conditions for them — dappled shade, consistent moisture, and the organic matter that builds up under deciduous trees aligns well with what hostas need. The ‘Sum and Substance’ variety (massive chartreuse leaves, one of the largest available) and ‘Halcyon’ (blue-grey with outstanding slug resistance) both perform reliably across all PA zones.

The critical management factor is consistent summer moisture. Periods of drought — most common in August in inland zones — cause leaf edges to brown and crisp. A 3-inch layer of organic mulch around the root zone and supplemental irrigation during dry spells resolves this almost entirely. In Zone 7a, sun-tolerant varieties like ‘Stained Glass’ and ‘Guacamole’ can handle morning sun better than standard hostas, which is practical in Philadelphia-area gardens where mature trees often cast less complete shade than expected.

Hydrangeas in Pennsylvania: Matching Variety to Zone

Hydrangeas are the statement shrub of Pennsylvania gardens — spectacular in bloom, available in every size from compact 3-foot mounds to 8-foot screening plants, and present in nearly every garden from Erie to Philadelphia. But variety selection makes or breaks hydrangea performance in Pennsylvania’s climate. Plant the wrong type and you either lose flower buds to late frosts every spring or get a shrub that never performs to its potential.

Zone 5 and 6 (Northern and Central PA): Smooth hydrangeas (Hydrangea arborescens) and panicle hydrangeas (H. paniculata) are the most reliable choices for the majority of Pennsylvania gardeners. Both bloom on new wood, meaning a hard winter that kills old stems does not prevent flowering — new growth produces flowers regardless. ‘Incrediball’ (smooth, massive white globes) and ‘Limelight’ (panicle, lime-green to white to pink) are consistently the strongest performers across Zone 5 and 6 trials. The ‘Endless Summer’ series of remontant bigleaf hydrangeas has extended bigleaf viability into Zone 5b, but reliability still lags behind smooth and panicle types in genuinely cold winters.

Zone 7a (Philadelphia area): Bigleaf hydrangeas (H. macrophylla) — the classic mophead type — are fully reliable in Philadelphia and the Delaware Valley. Nikko Blue, Endless Summer, and Let’s Dance series all perform well. Philadelphia-area gardeners can also grow oakleaf hydrangeas (H. quercifolia), which offer ornamental exfoliating bark and outstanding fall color in addition to summer flowers. Soil pH controls flower color in bigleaf hydrangeas: acidic soil (pH below 6.0) produces blue; more alkaline soil (pH above 7.0) produces pink. Pennsylvania’s naturally acidic Appalachian soils lean toward blue; the more calcareous soils of the Ridge and Valley region often produce pink or purple tones without amendment.

For the full guide to pruning timing, feeding, pH adjustment, and variety selection for every hydrangea species, see our complete hydrangea growing guide.

Deer-Resistant Plants for Pennsylvania

Deer pressure is one of the most significant challenges in Pennsylvania gardening. The state has one of the highest white-tailed deer densities in the US — the Pennsylvania Game Commission estimates 30 or more deer per square mile in some rural counties, and suburban pressure in Montgomery, Chester, Bucks, and Lancaster counties is substantial. Even urban Philadelphia gardens near Wissahickon Valley Park or Fairmount Park experience regular browsing.

We cover this in more depth in gardening in Ohio.

“Deer-resistant” is a relative term. A hungry deer in late winter will eat almost anything when snow covers preferred food sources. But the plants below are consistently low on the deer preference list in Pennsylvania, either because of aromatic foliage, toxic compounds, or coarse textures deer find unpalatable.

Deer pressure intensifies from January through March when natural food sources are depleted. Protecting new transplants with wire cages for the first two growing seasons gives them time to establish before they become less appealing targets. For vegetable gardens, 8-foot fencing is the only reliably effective deterrent for persistent deer populations.

Companion Planting in Pennsylvania Vegetable Gardens

Companion planting is particularly valuable in Pennsylvania gardens where pest pressure from Japanese beetles, squash vine borers, and tomato hornworms can significantly reduce yields. The key is distinguishing which companion relationships have documented evidence from those that are simply garden folklore.

French marigolds (Tagetes patula) are the best-evidenced companion plant for Pennsylvania vegetable gardens. Their roots produce alpha-terthienyl, which suppresses root-knot nematodes in surrounding soil, and their foliage releases limonene, which has been shown in controlled trials to significantly reduce whitefly populations on adjacent tomatoes. Both mechanisms are peer-reviewed — placing marigolds in a different category from most companion plant claims.

Plant French marigolds on the same day as tomatoes or peppers, not weeks later. The benefits require simultaneous establishment; marigolds do not retroactively address existing infestations. As a border planting around raised beds, they also deter Japanese beetles from entering the bed by providing a physical and olfactory buffer.

Basil planted alongside tomatoes has a more limited documented benefit, but it reliably attracts beneficial insects and acts as a trap crop for aphids. For the complete evidence-based breakdown of what works and what does not across vegetable companion planting combinations, see our companion planting guide.

Best Plant Varieties for Pennsylvania Zones 5, 6, and 7

Variety selection is where zone knowledge delivers the most direct return. Days to maturity matters most in Zone 5, where the warm-season window is 60–70 days shorter than Zone 7a. Choosing a 90-day tomato for an Erie garden (where soil reliably warms by late May) means harvesting in late August at best — with the first fall frost arriving by mid-October.

For blueberries specifically, Pennsylvania’s naturally acidic soils in the Appalachian region are exceptionally well-suited to cultivation without significant pH amendment. Target pH 4.5–5.5 — most native woodland soil in Pennsylvania sits in this range. The Ridge and Valley region has more variable pH; Penn State Extension soil testing costs $9–$15 and includes lime and fertilizer recommendations calibrated to your actual results. It is the single most cost-effective step any Pennsylvania gardener can take before planting fruit or perennial beds.

Seasonal Planning and Zone Migration

Pennsylvania gardeners have seen measurable changes in growing season length over the past three decades. Average last frost dates have moved 7–10 days earlier across most of the state since the 1990s, and the 2023 USDA zone update reflects this shift: Philadelphia and Reading moved into Zone 7a, portions of the Lehigh Valley shifted from 6a to 6b, and some suburban Pittsburgh areas nudged into 6b. Plants previously considered zone-risky — camellias in the Lehigh Valley, crape myrtles in Delaware County — are now worth attempting where sheltered microclimates provide additional winter protection.

This shift is ongoing, not a one-time adjustment. For a broader look at how changing hardiness zones are affecting planting decisions across the US and what it means for long-term garden planning, see our guide to climate zone migration.

Planning a full Pennsylvania growing year requires balancing cool-season spring crops, warm-season summer production, and fall re-planting — all with zone-appropriate timing. Our year-round seasonal planting guide covers the complete monthly sequence with soil temperature triggers alongside calendar dates, giving you the most accurate planting windows regardless of how your specific season tracks against the average.

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Frequently Asked Questions

What growing zone is most of Pennsylvania?

Most of Pennsylvania falls in Zone 6a or 6b. Zone 5 covers the northern highlands and Pocono Plateau. Zone 7a is limited to the southeastern corner, primarily Philadelphia and surrounding counties. If you live in Pittsburgh, Harrisburg, Allentown, or Scranton, you are most likely in Zone 6.

When should I plant tomatoes in Pennsylvania?

Zone 7a (Philadelphia): after April 15, or when soil consistently reads 60°F. Zone 6 (Pittsburgh, Harrisburg): after May 1–10. Zone 5 (Erie, State College): after May 15, when soil temperature is reliably at or above 60°F. These dates assume hardened-off transplants started indoors 6–8 weeks earlier, not direct seeding.

Do hydrangeas survive Pennsylvania winters?

Yes, with the right variety. Smooth hydrangeas (Incrediball, Annabelle) and panicle hydrangeas (Limelight, Bobo) survive Pennsylvania winters across all three zones without protection because they bloom on new wood. Bigleaf hydrangeas are reliable in Zone 7a; in Zones 5–6, choose remontant varieties like ‘Endless Summer’ that can rebloom on new growth if winter damages old buds.

What is the best soil amendment for Pennsylvania gardens?

Compost is the single most useful amendment across all Pennsylvania soil types. Pennsylvania’s common clay soils in the Piedmont region benefit from compost worked in at 3–4 inches per year, which improves both drainage and water retention simultaneously. Before amending for specific crops like blueberries or acid-loving plants, get a Penn State Extension soil test first — it identifies your actual pH and nutrient levels rather than requiring you to guess.

Which plants are most deer-resistant in Pennsylvania?

Hellebores, foxglove, catmint, lavender, Russian sage, and ornamental grasses are among the most reliably deer-avoided plants in Pennsylvania landscapes. Native echinacea and black-eyed Susan are also rarely browsed once established. Hostas are highly attractive to deer and generally need wire caging protection for the first season — or indefinitely in high-pressure areas.

What native trees work best in Pennsylvania gardens?

Eastern Redbud (Cercis canadensis) is among the most garden-worthy native trees for all PA zones — spectacular pink bloom in early April, heart-shaped foliage through summer, and yellow fall color. Serviceberry (Amelanchier) offers three-season interest (spring bloom, early summer berries for birds, fall color) and fits well in smaller gardens. American Fringe Tree (Chionanthus virginicus) is slower-growing but outstanding in bloom and strongly deer-resistant.

Sources

1. Penn State Extension. Vegetable Gardening. Penn State Extension Service.
2. Penn State Extension. Soil Testing. Penn State Extension Service.
3. USDA Agricultural Research Service. USDA Plant Hardiness Zone Map, 2023 Edition. USDA ARS.
4. Penn State Extension. Home Gardening Resources. Penn State Extension Service.