Millcreek, PA Invasive Plant Rules: Prohibited Species (2026)

Millcreek Township regulates invasive trees through its street tree standard, § 29-46 in Chapter 29, Part 2 of the Township Code. By its own terms the section governs whenever trees are placed, maintained or replaced within the right-of-way of a public street, so it covers new plantings and replacements alike. It is a street standard enforced by the Township, not a ban on every plant in a private yard.

Two layers apply. Section 29-46D(4) says trees known to have invasive characteristics that can escape and spread are to be avoided, and that no tree on the Department of Conservation and Natural Resources list of "Invasive Plants of Pennsylvania" (current edition) is authorized. Because the code points to the current edition, a species added to that list later is caught without a Township amendment. Section 29-46D(5) then prohibits six species by name: Norway maple (Acer platanoides), sycamore maple (Acer pseudoplantanus), tree-of-heaven (Ailanthus altissima), empress tree (Paulownia tomentosa), Callery pear (Pyrus calleryana) and Siberian elm (Ulmus pumila). Norway maple and Callery pear carry an asterisk, which the code defines as having cultivars not known to be invasive. The sentence opens with "Among others," so the six names are a floor, not the full list.

Approved trees have to meet the selection standard in § 29-46D(1): a type whose root structure will not damage paved streets or sidewalks, hardy to the local climate and without invasive characteristics. The code lists suitable species drawn from the Pennsylvania State University street tree sources, including red maple (Acer rubrum), littleleaf linden (Tilia cordata) and sunburst honeylocust. Any other species needs Township approval backed by information the Township accepts, and tree varieties are subject to approval of the Board of Supervisors under § 29-46C(1). Trees must be nursery-grown and a minimum of two inches in caliper, measured six inches above finish grade.

Planting comes with a guarantee. Under § 29-46E(3), street trees are maintained and guaranteed for a minimum of one year after planting, and a tree is replaced if more than 1/3 of it dies during that period. Replacement trees must meet every requirement of the section and carry a guarantee of a minimum of two planting seasons.