While the City of Houston Landscape Ordinance and the Harris County Landscape Ordinance are remarkably similar, there are some critical differences as well.
Street Trees: One tree (minimum 1 1/2″ caliper, 6′ tall) is required per 30 feet of street frontage. Hint: You cannot deduct approaches. The dimension you show must match the dimension shown on the property line. Another Hint: When quantifying the number of street trees required, round up (even if less than .5). Hint #3: All streets must be measured, and calculations made, independently – you cannot combine the sum of all street frontage distances and divide that by 30.
In either case, the street trees must be spaced no less than 20′ on center – whether they are existing trees or proposed.
The City of Houston prefers that you plant the street trees in the right of way. That said, they will also allow the proposed trees to be placed within 10′ of a local street right of way or within 25′ of a major thoroughfare. Harris County will not allow trees to be planted within the right of way.
Both the City of Houston as well as Harris County require a species of tree to be chosen from the City of Houston Street Tree List.
Parking Lot Trees: One tree (minimum 1 1/2″ caliper, 6′ tall) is required per 10 parking spaces. Hint: When quantifying the number of parking lot trees required, round down if .4 or less or round up if .5 or more. At least 50% of the required parking lot trees must from from those trees listed as Large Trees from the City of Houston Parking Lot Tree List. Another Hint: In addition to the one tree per ten spaces, you must also ensue that there is a tree planted within 120′ of each parking space. Therefore, you could be required to design/plant more parking lot trees than the 1:10 ratio.
Both the City of Houston as well as Harris County require a tree to be selected from the City of Houston Parking Lot Tree List.
Shrubs: Ten shrubs (minimum 18″ tall at the time of planting) are required for every one required Street Tree. Yes, there is a City of Houston Shrub List as well. Hint: At least 75% of the required shrubs must be planted along the perimeter of the parking lot (on private property – not in the right of way). The remaining 25% can be planted anywhere on site.
Existing Trees: The handling of existing trees is where the majority of the differences come in between the City of Houston Landscape Ordinance and the Harris County Landscape Ordinance.
City of Houston: A protected tree means a corridor tree, designated tree, green corridor tree, or parkway tree.
- Corridor Tree: A tree of a species listed on the street tree list that has a caliper of 20″ or more and is situated in the building setback area along a local street or along a major thoroughfare, other than a portion of a major thoroughfare that has been designated as a green corridor.
- Designated Tree: A specific tree designated by the city council as having particular historical or arboricultural significance.
- Green Corridor Tree: A tree of a species listed on the street tree list that has a caliper of 15″ or more and is situated in the building setback area of a green corridor.
- Green Corridor: Any portion of a major thoroughfare that has been designated as a green corridor.
- Parkway Tree: A tree of a species listed on the street tree list that is situated in the parkway area adjacent to any tract or parcel of land and that has a caliper equal to or greater than 1 1/2″.
- Parkway: The area lying between the street curb or the edge of the roadway paving and the adjacent property line.
The removal of protected trees in the City of Houston must receive approval from the City of Houston Parks & Recreation’s Urban Forestry Department. This is a separate application than the Planning Department application for building permit. You can reach them via email at forestryplanreview(at)houstontx.gov.
In the City of Houston, you may take credit for existing trees that will remain and fall under either the street tree requirements or the parking lot tree requirements (providing the tree species are on the approved respective lists and they meet the minimum size requirements of 1 1/2″ caliper and 6′ tall).
Harris County: The only protected trees are those within the right of way. That said, you can take credit for existing trees on private property that are to remain – with the same criteria as I have listed above for the City of Houston.
FINAL HINT: Just because a tree or shrub is listed on an approved list does not necessarily mean that it is readily available from wholesale nurseries local to the area. Also, just because a shrub is listed on the approved shrub list, does not mean that it will be readily available from a local nursery at the minimum 18″ height requirement. We run up against this frequently in the projects we design across the U.S. This is one of the reasons you should select a Landscape Architect in Houston TX that is not only familiar with the local landscape ordinances, but the plant material as well. Evergreen Design Group’s history leads back to the Houston, Texas area…that is where we got our start.
At the time of this writing, our Landscape Architects are registered in AL, AR, AZ, CA, CO, CT, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, MI, MN, MO, MS, MT, NC, NJ, NM, NY, OH, OK, PA, SC, TN, TX, UT, VA, WA, WI and WY.