Can I Grow London Plane in Pennsylvania?

London Plane in Pennsylvania — the short answer

Pennsylvania is not one climate

Where in Pennsylvania Fits Best

Even within Pennsylvania's zones 5b-8a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for london plane (USDA PHZM 2023):

Zone Comparison

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant London Plane in Pennsylvania

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.

Growing Season Fit

The zone check says london plane survives winter here. Whether the season is long enough — and warm enough — is a different question.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

London Plane tolerates a wide pH range (pH 3-10) — 7 units, acid ground through alkaline — so soil acidity is rarely what limits it in Pennsylvania. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 4.5 and 8.5 — worth knowing before you decide whether a Pennsylvania soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Pennsylvania site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Pennsylvania soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

What Else to Consider for London Plane in Pennsylvania

Zone compatibility tells you about winter cold survival — but Pennsylvania growers also need to think about:

What to actually do about these — and the constraints that apply to every Pennsylvania grower, not just london plane — is covered on the Pennsylvania growing guide.

Where in Pennsylvania London Plane Is Zone-Hardy

London Plane is rated for USDA zones 4–8. Every one of Pennsylvania’s 67 counties sits inside that band — from Cambria County at zone 5b to Philadelphia County at zone 7b — so winter cold is not what decides this plant anywhere in the state. What is left to vary is your own parcel: slope, shelter and cold-air drainage routinely move a site half a zone either way from the county figure.

Across those 67 counties Pennsylvania’s winter-low ladder runs from zone 5b in Cambria County to zone 7b in Philadelphia County — 2 USDA zones of spread, which is 20°F between the two counties’ average coldest night of the year. That is why a statewide hardiness answer is where you start and not where you finish.

The planting window moves with it. Potter County holds its last hard freeze (28°F) until about May 5, while Philadelphia County is clear by Mar 19 — 47 days apart. Set london plane out on your county’s date, not the state’s.

County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F killing freeze — earlier than the folk 32°F "last frost". London Plane’s zone 4–8 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.

Pennsylvania Cooperative Extension

For Pennsylvania-specific cultivar recommendations, planting calendars, and pest pressure for london plane, the canonical source is Penn State Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

What pests threaten london plane in Pennsylvania?

Japanese beetle is documented in Pennsylvania and will find london plane, but it is manageable here. What an experienced grower watches for, and does:

Japanese beetle

Worth watching

The University of Kentucky lists this among the landscape plants Japanese beetles are most likely to attack, and the skeletonized, lace-like leaves can look alarming. But the honest calibration is the University of Minnesota's: a healthy, established tree, shrub or vine tolerates a lot of this feeding without significant, long-term injury — in most cases the damage is cosmetic and will not kill the plant.

What to do: For an established planting the move is to leave it be and keep it watered through the four-to-six-week flight — a vigorous plant outgrows feeding that looks worse than it is. Young or already-stressed plants are the exception and worth hand-protecting: knock beetles into soapy water in the cool of morning, when they are slow. The one thing not to hang is a Japanese beetle trap — University of Kentucky research found the lures pull in far more beetles than they catch.

Documented range: states listed as Japanese-beetle infested · University of Kentucky Entomology, University of Minnesota Extension, National Plant Board

The full japanese beetle playbook

Only pests whose documented range and host relationship both trace to a primary source appear here — so a quiet section means we have nothing sourced to tell you, not that your garden is pest-free.

Common Questions About Growing London Plane in Pennsylvania