Local zoning · Hillsborough

Hillsborough — Landscaping and Screening

Landscaping and Screening under the Hillsborough local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page summarizes what the Hillsborough Zoning Ordinance (Title 17) requires for landscaping and screening — trees, fences/walls, screening plantings, design review and permits — with a focus on the town's actual local rules. It pulls the controlling ordinance language (Title 17) and explains how screening requirements interact with development rules such as setbacks, lot coverage, and ADU/two‑unit project standards. For the broader zoning map and where each rule applies, see the Hillsborough zoning overview and the town's Zoning pages.

What the code says (quick map)

  • The town’s dedicated landscaping chapter is Chapter 17.56 (Purpose; Definitions; required landscaping; projects subject to review; design review; permits; deadlines) — see § 17.56.010–§ 17.56.090 for the core program and definitions such as "protected tree" and "grove".
  • Evergreen screening rules tied to small‑scale projects appear in the ADU rules (Chapter 17.52) and in the two‑unit project chapter (Chapter 17.54) — both require evergreen landscape screening between units and neighbors (plant size and spacing specified).
  • Landscaping must follow the town’s water‑conservation landscaping requirements (Chapter 15.29), and many landscaping triggers are subject to design review under the town’s design review rules.

Note: where the ordinance ties development standards to a zoning district, consult the town’s Development Standards page and the district rules below.

District-by-district breakdown (landscaping & screening implications)

RD-1 (Traditional residential)

  • Purpose: RD-1 preserves single‑family character; density cap is one dwelling per 0.5 acre. Typical permitted uses include single‑family dwellings, accessory structures, country club, public parks; consult the uses table in § 17.16.010(B).
  • Landscaping/screening rules that commonly apply:
    • All developed property must be landscaped; the town allows natural state retention only if properly maintained for fire safety and other purposes (§ 17.56.030).
    • Standard setbacks that determine where screening can be planted: front/street setback = 25 ft, interior setback = 20 ft (see measurement rules for how these are measured) — these limits affect where fences and hedges may go (§ 17.24.020, § 17.24.030).
    • Lot coverage and softscape limitations affect how much space is available for planting (see § 17.32.060; maximum combined structural + hardscape generally ≤ 50% of net lot area).
  • Practical note: taller screening or solid fences in the setback or near building envelopes typically require design review; retaining walls in setbacks are limited to maximum heights and must be screened (§ 17.24.010(B)(1), § 17.28.030).

RD-2 (Mixed residential)

  • Purpose: RD-2 allows townhomes and multifamily on select town‑owned land; minimum density 20 units/acre. Typical permitted uses include multifamily housing, town facilities and public parks; see § 17.16.010(B).
  • Landscaping/screening rules that commonly apply:
    • Multi‑unit projects normally trigger more extensive landscape plans and are more likely to be subject to design review and the landscaping permit processes in Chapter 17.56 (definitions, water conservation, permit triggers such as large rehabilitations, tree removals) — see § 17.56.050–§ 17.56.070.
    • Parking and circulation layout standards in Chapter 17.36 intersect with planting islands, perimeter screening and setbacks; planting in parking areas must respect those parking rules. For parking technicals, see the town’s Parking page.
  • Practical note: where RD‑2 projects abut RD‑1 parcels, expect conditions that require evergreen screening and carefully sited plantings to preserve privacy and meet objective design standards.

RD-3 (Governmental & residential mixed-use)

  • Purpose: RD-3 is limited to certain town‑owned lands for government/town facilities and limited residential; consult § 17.16.010(B) for permitted uses and limits (max 16 units on land zoned RD‑3).
  • Landscaping/screening rules that commonly apply:
    • Public buildings and town facilities have specific setback and screening directions (e.g., playgrounds/athletic fields must have planted buffers from adjacent nonschool property) — see the public/private school and playground rules for analogous requirements (§ 17.16.010 cross‑references).
    • Public projects will be reviewed under standard landscape rules in Chapter 17.56 and may require formal plans showing drought‑tolerant plantings per Chapter 15.29.

Key landscaping & screening standards (decision table)

Rule / Requirement What the code requires (decision‑relevant) Code reference
Landscaping chapter purpose & definitions Town landscaping program; "tree" and "protected tree" definitions; “grove” defined § 17.56.010–§ 17.56.020
Projects requiring review Tree removal of a protected tree; moving ≥ 50 cubic yards of dirt; rehabilitating > 10,000 sq ft of landscaping; synthetic turf visible from ROW; grove removal § 17.56.050
Design review for landscaping Landscaping projects listed above require design review (Type B) prior to permits § 17.56.060
Evergreen screening (ADUs) At least one 15‑gal plant per 5 ft of exterior wall (or 24‑in box per 10 ft); ground‑level specimens ≥ 6 ft; 2nd‑story specimens ≥ 12 ft; drought‑tolerant § 17.52.020 (E)(11)(b) (ADU landscaping requirements)
Evergreen screening (two‑unit projects) Same minimum spacing: 15‑gal per 5 ft (or 24‑in box per 10 ft); plants ≥ 6 ft when installed; alternative: solid fence ≥ 6 ft Chapter 17.54, Landscaping subsection (two‑unit projects)
Water‑conserving landscaping Landscaping must comply with town water‑conservation rules (Chapter 15.29) § 17.56.040
Tree removal & replacement Protected trees (cumulative ≥ 18 in diameter) regulated; tree permit for protected tree removal and replacement rules; “tree” elsewhere may use 6 in or 12 in thresholds in different program sections — verify case‑by‑case § 17.56.020, plus project chapters (see 17.52, 17.54)
Deadline to install landscaping New‑residence landscaping must be completed within 6 months after issuance of certificate of occupancy; other timelines vary (final inspection deadlines) § 17.56.090(A)–(C)
Security / bond Building department can require a bond to guarantee landscaping installation § 17.56.080

How design review, permits, and other rules interact

  • If your project triggers any items in § 17.56.050 (for example, removing a protected tree or rehabilitating > 10,000 sq ft), the plan must obtain design review approval per § 17.56.060 before building permits are issued.
  • Landscaping plans that fall under the water‑conservation rule must include irrigation plans and grouping of high‑water‑use plants; the building department requires that irrigation plan when § 17.56.040 applies.
  • Evergreen screening requirements for ADUs are objective (plant sizes and spacing specified) and are part of the ADU clearance process (ADUs are otherwise ministerial but include notice and specific objective landscaping requirements) — see the ADU rules and the town ADU page. Link to Hillsborough ADUs.

(For design review procedural rules consult Hillsborough’s Design Review page.)

Checklist (what an applicant must satisfy for typical screening/landscape work)

  • Confirm whether work triggers Chapter 17.56 review (protected tree removal, ≥ 50 cu yd earthwork, > 10,000 sq ft rehab, synthetic turf visible from ROW, grove removal) — § 17.56.050.
  • If triggered, obtain design review approval prior to building permits (§ 17.56.060).
  • Submit landscaping permit application to building department with required fees and (when applicable) irrigation plan showing drought‑tolerant plantings per § 17.56.040 and Chapter 15.29.
  • If removing any protected tree, file the tree removal permit and replacement plan; confirm protected tree diameter threshold and replacement ratios in the applicable chapter (§ 17.56.020).
  • For an ADU or two‑unit project, include evergreen screening per the ADU/17.52 or two‑unit/17.54 rules (plant size, spacing, or 6‑ft solid fence alternative).
  • Expect possible bonding/security to ensure installation and a final inspection within the prescribed deadlines (§ 17.56.080–§ 17.56.090).
  • Check setbacks and lot coverage (setbacks 25 ft front / 20 ft interior; lot coverage limits; building envelopes under 17.28) before sizing fences/planting beds (§ 17.24.020, § 17.32.060, § 17.28.010).

Risks & Ambiguities

Issue Why it matters What to verify
Conflicting tree thresholds in code extracts Different chapters reference "tree" or "protected tree" with different diameters (6", 12", 18") in various program contexts; enforcement could depend on which chapter applies Verify which chapter applies to your parcel/project (ADU, two‑unit, general landscaping, street/tree program) and confirm the exact definition used for "protected tree" in that application (verify with Planning/Building) — see § 17.56.020 and the project chapter(s).
Where screening may be placed relative to setbacks Setbacks (front 25 ft, interior 20 ft) and building envelope rules limit planting or fence placement that can serve as screening Confirm placement with the measuring rules in § 17.24.020–17.24.030 and the building envelope in § 17.28.010; design review required if screening/fence encroaches into a regulated area.
Interpretation of "drought‑tolerant" and water‑conservation plan detail Chapter 17.56.040 requires compliance with Chapter 15.29 but the code does not include the full plant list or irrigation detail here Provide irrigation and planting plans prepared to Chapter 15.29 requirements; confirm acceptable plant lists with planning staff.
Overlap with fire/hazard rules (very high fire hazard zones) Fire authority rules may require different hardscaping, fuel reduction, or non‑combustible buffers that conflict with dense evergreen screening Check the property's fire hazard severity and coordinate with the fire authority and see the two‑unit chapter L/G fire‑hazard mitigation provisions. Verify with the Central County Fire Department.
Objective vs. discretionary review for ADUs ADU projects are largely ministerial, but the ADU rules include objective landscaping and notice obligations that must still be met ADU applicants must install evergreen screening per § 17.52.020(E)(11)(b); comply with notice and building/fire code obligations.

Plain-English summary

Hillsborough requires every developed property to be landscaped, protects larger or specified “protected trees,” and requires design review and permits for significant landscape changes (tree removal, big earthwork, large rehab, visible synthetic turf). ADUs and two‑unit projects must provide evergreen screening between units and neighbors (explicit spacing and minimum plant heights or a 6‑ft fence alternative); all landscaping must follow the town’s water‑conservation rules and, where applicable, be bonded and inspected before final approvals. Key rules live in Chapter 17.56 (landscaping), the ADU chapter (17.52), the two‑unit chapter (17.54) and the setbacks/lot coverage chapters — verify specifics with planning staff for parcel‑specific cases.

Source References

  • Hillsborough Zoning Ordinance (Title 17) — Chapter 17.56 (Landscaping): § 17.56.010–§ 17.56.090 (purpose, definitions, triggers, design review, permits, deadlines).
  • ADU landscaping requirements and evergreen screening (ADU chapter, Chapter 17.52, ADU planning permit subsections, including landscape requirements).
  • Two‑unit projects — landscaping and evergreen screening (Chapter 17.54, landscaping subsection and project requirements).
  • Setback measurement and location rules (Chapter 17.24.020–17.24.030).
  • Residential lot coverage, structural/hardscape/softscape definitions and tables (§ 17.32.060 and Table 17.52.020‑1).
  • Design review applicability for landscaping projects (§ 17.56.060; cross‑reference to design review procedures).

Internal links (first natural mentions above): Hillsborough zoning overview, ADUs, Design Review, Parking, Development Standards, Overlay Districts, California Building Standards Code.

Sources

Retrieved passages

  • Hillsborough Zoning Code (§ 3) High relevance
  • Hillsborough Zoning Code (§ 26) High relevance
  • Hillsborough Zoning Code (chapter unless) High relevance
  • Hillsborough Zoning Code (§ 17) High relevance
  • CWUIC § 65850.6 (Title 24) High relevance
  • California Fire Code (chapter unless) High relevance
  • Hillsborough Zoning Code (Section 65915) High relevance
  • Hillsborough Zoning Code (Chapter 17.54) High relevance
  • Hillsborough Zoning Code (Section 17.56.010.) High relevance
  • California Fire Code Medium relevance
  • California Building Code Medium relevance
  • Hillsborough Zoning Code (Section 17.24.030) Medium relevance
  • California Building Code Medium relevance
  • Hillsborough Zoning Code (Title 17) Medium relevance
  • Hillsborough Zoning Code (chapter if) Medium relevance
  • Hillsborough Zoning Code (chapter if) Medium relevance
  • Hillsborough Zoning Code (Section 21155) Medium relevance
  • Hillsborough Zoning Code (section is) Medium relevance
  • Hillsborough Zoning Code Medium relevance
  • California Fire Code (chapter is) Medium relevance
  • Hillsborough Zoning Code (§ 16) Medium relevance
  • Hillsborough Zoning Code (chapter must) Medium relevance

Cited sections

Frequently asked questions

What is required before I remove a tree on my Hillsborough property?

You must check Chapter 17.56: removing a protected tree (as defined in § 17.56.020) triggers the landscaping permit process and in many cases requires a tree removal permit and replacement planting or other mitigation; protected trees are specifically regulated and removal often requires design review/permit approval under § 17.56.050–§ 17.56.070. Verify tree diameter thresholds and replacement rules with planning staff.

Do ADUs in Hillsborough have screening requirements?

Yes. ADUs must provide evergreen landscape screening between the ADU and adjacent parcels: minimum plant density of one 15‑gal plant per 5 linear feet of exterior wall (or one 24‑in box per 10 feet); ground‑level plants must be ≥ 6 ft at installation (second‑story ADUs require ≥ 12 ft specimens) — see the ADU landscaping subsection in § 17.52.020. A solid 6‑ft fence is an alternative for ground‑level ADUs.

Which landscaping projects require design review in Hillsborough?

Design review is required for landscaping projects listed in § 17.56.050 — that includes protected tree removals, moving or adding 50 cubic yards of soil, rehabilitating more than 10,000 sq ft of landscaping, installing landscaping for a newly constructed residence, synthetic turf visible from the right‑of‑way, and grove removal — and per § 17.56.060 those listed projects require Type B design review before permits.

Can I use a fence instead of plants for screening?

The code explicitly allows a solid fence of at least 6 ft as an alternative to evergreen specimens in ADU and two‑unit project screening requirements (where specified) — see the ADU landscaping rules in § 17.52.020(E)(11)(b) and the two‑unit project landscaping subsection. Verify whether the fence location would conflict with setback/height/retaining wall rules.

Where are I allowed to plant screening relative to setbacks and lot coverage?

Setbacks are generally 25 ft (street/front) and 20 ft (interior) as defined in § 17.24.020, and lot coverage rules limit the space available for softscape vs hardscape (see § 17.32.060 and Table 17.52.020‑1). Planting and fences within setbacks may be limited (and retaining walls in setbacks have maximum heights and screening obligations), so confirm measurement points and permitted encroachments before finalizing plans.

Does Hillsborough require drought‑tolerant plants?

Yes. The landscaping chapter requires compliance with town water‑conservation landscaping requirements (Chapter 15.29) and several project rules (ADU and two‑unit rules) explicitly require drought‑tolerant plantings. Submit irrigation plans where required (§ 17.56.040 & ADU/two‑unit landscaping subsections).

How long after construction must landscaping be finished?

Landscaping installed with a new residence must be completed within 6 months after issuance of the certificate of occupancy; other project deadlines are set depending on the design‑review schedule or within one year of sheetrock nailing inspection for other construction types — see § 17.56.090(A)–(C).

Are retaining walls and their exposed faces required to be screened?

Yes — terraced retaining walls and exposed retaining wall faces are required to include landscape screening; retaining wall heights in setbacks are limited (see § 17.24.010(B)(1) and § 17.28.030) and landscaping for retaining walls is subject to design review.

Who enforces fire‑related restrictions that could affect screening?

The code references fire‑hazard mitigation for lots in very high fire hazard severity zones (e.g., access, sprinklers, water reserves) in project chapters (e.g., two‑unit rules) — but fire authority requirements (and the statewide Wildland‑Urban Interface rules) can impose additional restrictions on plant selection and placement. Verify with the fire authority (Central County Fire) for parcel‑specific requirements.

If I propose synthetic turf, will it be reviewed?

Yes — synthetic grass visible from the public right‑of‑way is specifically listed as a landscaping project subject to the review and permit procedures in § 17.56.050. Expect design review and permit requirements. ---

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