Plants & Vegetation

Choosing the Right Vegetation for Your GreenGrid® Vegetative Green Roof

Vegetation is the heart of any vegetative green roof system. While substrate and growing medium are essential engineering components, the plants you choose are critical to the system’s long-term success. At GreenGrid®, our experienced horticulturists help you select vegetation tailored to your roof’s unique conditions.

Why Plant Selection Matters

Plants need three essentials to survive and thrive:

Light
Water
Macro and micro-nutrients

However, rooftop environments are often harsh:

Intense sunlight
Limited water retention
Exposure to wind and temperature extremes

Choosing the right plants for rooftop conditions—not typical garden plants—is key to a successful green roof.

Using Herbaceous Perennials

While succulents form the backbone of extensive green roofs, herbaceous perennials can be used as accent plants to add color and texture. Keep in mind:

Most have limited drought tolerance
Best used sparingly without supplemental irrigation
Some promising species include:
- Alliums
- Dianthus
- Phlox
Regional and site-specific factors should guide your choices

Options for Intensive Green Roofs

Intensive green roofs have deeper growing mediums (8 inches or more), allowing for a wider range of plants such as:

Perennials
Native grasses and forbs
Herbs and vegetables
Small shrubs

GreenGrid® offers modules with 8-inch depth to support these plants. Incorporating native species may also help earn LEED points by supporting local habitat restoration.

The GreenGrid® Advantage

Years of horticultural expertise
Customized plant recommendations based on your site
Support throughout your green roof design and installation process

For personalized plant selections and design assistance tailored to your project, please contact your GreenGrid® representative!

Design/Planting Recommendations

Intensive Vegetative Green Roof System plant selections may include varieties of ornamental and/or native: groundcovers, grasses, perennials, and in some instances trees and shrubs. Depending on the plant selection, an irrigation system is generally needed and since these rooftop gardens are similar to a backyard garden they will require varying degrees of long-term maintenance and care. When designing an intensive or rooftop garden, consultation with your GreenGrid® representative is strongly recommended; we have trialed numerous species and can help select proven performers for your project.

95% Coverage – Fully Mature System
Plants are grown to full maturity (approx. 95%+ coverage) under nursery care. Modules are grown out at our partner nurseries in accordance with the client specifications, delivered to the job site, and installed for an instant mature vegetative green roof. In addition to the instant aesthetic appeal, fully grown-out modules provide other functional benefits: a mature vegetative green roof is less susceptible to weed encroachment, and mature vegetation helps protect the growing medium from potential wind scour and water erosion. This translates to a successful vegetative green roof with less maintenance. Lead times vary; consult your GreenGrid® representative.

Sedum Mats – Fully Mature System
Sedum mats grown to full maturity can be either installed at the nursery prior to delivery or installed in concurrence with the modules on the rooftop. Mats are planted with Sedum cuttings and are composed of three primary species and a multitude of secondary species. This is an expensive option, but the advantage of instant coverage with short turnarounds makes this a potential option. Upfront watering (4 to 5 times per week for the first 45 days) is vital to long-term success. Consult your GreenGrid® representative for availability and lead times.

GreenGrid® Pre-Vegetated Modules: GreenGrid® modules are to be filled with GreenGrid® species desired by the client suitable for vegetative green roof applications. Plants are to be grown to various levels of maturity at the nursery prior to delivery and installation.

Extensive plant mix is typically composed of deciduous, semi-evergreen, and evergreen “base” species with “accent” species. The base mix is generally composed of five to eight species of Sedum with one to two accent species. Consult your GreenGrid® representative for plant recommendations.

Customized Plants and Urban Agriculture

The GreenGrid® system has been utilized for food production in installations across the US. It can successfully support a wide range of herbs and vegetable crops with appropriate maintenance and modified soils. Some examples are listed below.

Trillium Charter School , Portland, OR

“This project is a perfect example of a multi-functioning green roof where you not only have storm water management, but also a space designated for food production. Students are educated about sustainability and the numerous benefits of green roofs. (Courtesy Edible Skylines, LLC – Erin Altz)

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Daybreak Youth Homeless Shelter, Dayton, OH

“Our goal is to not just give them a safe place to live, but also a safe place to grow and mature and become healthy adults and taxpaying citizens”, said Linda Kramer, Daybreak’s CEO. To reach that goal, the shelter is using a rooftop garden. Kids can go work among the plants; therapy for many, as well as lessons in nutrition and self-esteem. (Courtesy wdtn.com)

Women’s Housing and Economic Development Co. / Intervale Green, Bronx, NY

Sponsored by WHEDco, this farm serves as a way for residents to learn how to plant seeds, properly harvest produce, compost and cook healthy meals. In 2010 the roof underwent a transformation. About half of the extensive modules on one roof area were removed and replaced with 8 inch deep modules which were then filled with acceptable growing soil. After the roof was reconfigured for farming, it was already mid summer. However, an astonishing 136.41 lbs of produce were still harvested in the late summer and fall. (Courtesy WHEDco)

Private Residence, Northern IL

This private residence has successfully experimented with a wide range of food crops, and played an integral role in honing the recommended list of plants for food production in the GreenGrid® System.