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Home My WebLink AboutA034 - Applicant Request to Initiate a Text Amendment Related to Rock Mulch Within Required Landscaping AreasITEM #:36 DEPT:P&H October 14, 2025 Staff Report REQUEST TO INITIATE A TEXT AMENDMENT RELATED TO ROCK MULCH WITHIN REQUIRED LANDSCAPING AREAS BACKGROUND: Representatives of the Iowa State University Research Park (ISURP) recently contacted City Council with a request to consider a text amendment to allow the use of rock mulch where the City standards require organic mulch material. The request is in response to a site condition where rock was inappropriately used for some of the front yard landscaping areas. Other areas of the site, such as the parking lot, are in compliance with the City’ landscaping requirements for use of organic mulch. During the final inspection for the site in fall 2024, staff alerted the property owner that the rock must be replaced with mulch to comply with City standards in order to obtain a final site approval. The property owner was given until July to make the change. Alternatively, the owner was informed of the opportunity to request that the Council change the city-wide standard as a way to keep the rock in place, which was the reason for the request earlier this summer. The City’s landscape standards were comprehensively rewritten and approved by the City Council in 2017. The City’s landscape standards focus on use of vegetation as ground cover with specific minimum plantings for front yard landscaping and parking lot landscaping. With adoption of the new standards, one of the questions discussed at that time was whether to continue with the living ground cover and use of organic mulch in required planters compared to a development community request to have an option to utilize rock. At that time, staff described the benefits for plant health with organic material compared to rock and contrasted the maintenance differences for the owner. Generally, rock is more expensive than organic mulch and has less annual maintenance. In 2017, staff compared landscape regulations from many other communities. Staff asked the City's landscape architect consultant to provide an opinion regarding the use of mulch compared to rocks. Use of rock versus mulch varied by community and in the landscape architect's professional opinion, mulch is better, but rock does not necessarily impede plant vitality. It was emphasized that plant vitality is more dependent on having soil with high organic content and performing general upkeep, rather than mulch type. Ultimately, City Council adopted a requirement for living ground cover or organic mulch for all parking lot planters and required landscaping in front yard areas, with an exception that rock can used for foundation planting areas. Incidental or decorative landscaping with rock elements can also be allowed within larger landscaped areas. 1 Since 2017, there have been 1-2 incidents per year where staff inspects a site for a final building permit and finds that rock has inappropriately been placed on the site. When this occurs, they are required to remove the rock and put in mulch, which is situation of the ISURP. OPTIONS: The issue of rock for landscaping cover is a city-wide issue that is not unique to the Research Park. Required landscaping is a component of all multi-family apartment development and for commercial/industrial development. Residential and nonresidential uses have similar requirements for planting, with more sensitivity for residential areas compared to commercial areas. The organic mulch standard itself is designed to enhance landscape vitality with higher moisture retention and lower heat gain compared to rock. Secondarily, it does have an aesthetic component where large expanses of rock may not meet the intent of landscaping for “softening” of the urban environment and for visual interest. If the Council were to consider changing the requirement, staff has identified four options for changes. The fifth option is to make no changes. Option 1: Initiate a Text Amendment by the Applicant to eliminate the prohibition on rock mulch within required front yard planters. This option fits the ISURP request. The rock at question is within a planting bed of front yard landscaping. If this was approved, rock would still be limited to areas with planting just as mulch is now. It would not replace the requirement for use of grass and other ground cover as the means of meeting overall site landscaping requirements. All other planting and organic soil requirements would remain. This option works best when there are other landscape materials in the front yard to address aesthetics and the front yard is not solely rock beds with limited landscape plantings. Option 2: Initiate a Text Amendment by the Applicant to eliminate the prohibition on rock mulch within required front yard planters and within parking lots. This option fits the ISURP request, but goes beyond the ISURP issue and addresses mulch for required planters within parking lots. There is an argument of consistency to treat all landscape planters the same even though parking lots have much more hardscaped and paved areas than front yards. With this option the typical tree plantings in parking lots would still occur and there would likely need to be some more emphasis on some living ground cover or ornamental planting to fill in the planter area with the rock mulch. Option 3: Initiate a Text Amendment by the Applicant to Include Rock Elements Expressly within the Alternative Design Compliance Process. The current alternative design processes are focused on planting flexibility and does not address other basic design elements for landscaping. This option would allow for approval of an alternative design when the rock is an accent material and enhance the aesthetics of the landscape plan. Due to the overall landscape plan of the Innovation Center site, staff believes that if this option 2 existed it could be approved for the current landscaping. This option maintains the mulch requirement for sites unless an alternative and enhanced plan is approved. This could be either through an administrative alternative or through the current Alternative Landscape Plan process that is approved by the City Council. Option 4: Allow Rock as Replacement Material After Initial Installation. It is not uncommon for property owners over time to switch out mulch material from compliant materials to rock. This option would focus on use of mulch at the time of initial installation of planting to help support their initial vitality, but allow for owners to change out materials in the future. For this option to meet the interests of the ISURP for their current situation, some type of date exception would need to be included with approval of this change to maintaining your landscaping. Option 5: Maintain Current Requirement for Living Ground Cover or Organic Mulch in Landscape Areas. This option retains the current standards and no further action is needed from the City Council. The ISURP would be required to comply with the current requirements and remove the rock mulch in the required landscape areas. STAFF COMMENTS: The request for relief from the rock mulch requirement was part of the site inspection process, since the initial inspection there has been temporary occupancy allowances and extensions for compliant to allow for the ISURP to inhabit the building. Recent correspondence from the ISURP expressed concerns about upcoming deadlines on October 7 to receive a final approval or be subject to $40,000 building permit extension fee. The issue of a permit extension has been resolved and a final approval from Inspections has been granted. The issue of landscaping compliance is pending the outcome of this request. The City has enforced organic mulch and ground cover requirements for the past 25 years. Mulch is generally considered a better option for reducing heat and for moisture retention, but at the same time rock is a stable material and has maintenance benefits that some owners prefer even if the planting area is somewhat degraded. Rock can be aesthetic landscape treatment in some situations as well when integrated into an overall design. Staff’s primary concern about changing the standards regarding use of rock is to ensure it does not become a primary landscaping material in lieu of the plantings. Staff believes that issue can be addressed in a text amendment if Council elects to move forward with any of the options described above. ATTACHMENT(S): Landscape Examples.pdf 3 Landscaping Examples (outside of Ames) 4 5 6