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New Castle County, DE Tree Protection: Parkway Planting (2026)

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Planting rate: 1 large tree per 40 linear feet
Nonresidential interior streets: 1 tree per 50 linear feet
Minimum size: 3-inch caliper, balled and burlapped
Species diversity cap: No species over 20% of stock
Scope: Unincorporated New Castle County only

Summary

New developments in unincorporated New Castle County must plant street trees along road rights-of-way at a set rate per linear foot, sized and spaced under Sec. 40.23.151 of the Unified Development Code.

City-specific rules exist: Wilmington has its own parkway planting rules that differ from New Castle County's county-level regulations. If you live in Wilmington, check the city-specific page instead.

Large canopy street trees shall be planted on each side of the right-of-way at the minimum rate of one (1) tree per forty (40) linear feet of right-of-way. There is an exception for interior streets in nonresidential subdivisions not designated as arterials or collectors, wherein trees shall be planted on each side of the right-of-way at the minimum rate of one (1) tree per fifty (50) linear feet of right-of-way.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 5).

Full Breakdown

New Castle County's Unified Development Code requires street trees along the rights-of-way of new subdivisions and land developments in unincorporated New Castle County. Large canopy trees go in at one per 40 linear feet of frontage on each side of the road (one per 50 feet on non-arterial interior streets in nonresidential subdivisions), balled-and-burlapped, minimum 3-inch caliper, spaced at least 30 feet apart, with no single species exceeding 20% of a development's planting stock. The Department of Land Use reviews and must approve every landscaping plan before construction. Wilmington and Newark administer their own separate codes, not this one.

Violations & Fines

Landscaping plans that skip required street trees don't get Department of Land Use approval, so plan recordation and building permits are withheld until the plan complies.

Frequently Asked Questions

Does this rule apply inside Wilmington or Newark?

No. Wilmington and Newark run their own municipal codes and aren't covered by New Castle County's Unified Development Code street tree standard in Sec. 40.23.151.

How big do street trees have to be at planting?

Large or medium canopy trees must be at least 3-inch caliper, balled and burlapped, single-stemmed, and branched no lower than 6 feet above ground (8 feet near roads or walkways).

Can a developer use smaller trees instead?

Yes: a required large canopy tree may be substituted with one medium canopy tree or one and a half small/understory trees suitable for street planting, per Sec. 40.23.151.G.

Sources & Official References

[1]New Castle County Code § 40.23.151 (Municode)

Other rules in New Castle County

Heritage & Protected TreesSome Restrictions Protected Tree SpeciesSome Restrictions Landscaping Rules: CompostingLight Restrictions Environmental Rules: Coastal DevelopmentSignificant Restrictions Noise from Specific Sources: Delivery Truck NoiseSome Restrictions Code Violation Reporting: How to ReportSome Restrictions Water Use Rules: Leak Reporting DutySome Restrictions Sign Regulations: Window SignsLight Restrictions

All New Castle County rules

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Parkway Planting in Cities Across New Castle County

Wilmington, DE