Appropriate plant mix on green roof to qualify for SS 5

Nell, there aren't exacting USGBC definitions for diversity of habitat relative to this credit.USGBC defines "adapted vegetation" as "plants [that] reliably grow well in a given habitat with minimal winter protection, pest control, fertilization, or irrigation once their root systems are established. Adapted plants are considered low maintenance and not invasive."I would consult with your landcape architect to confirm that the plants selected meet that description, especially if they're not native. Having a mix of plants and knowing that those plants provide habitat for specific local fauna—a specific local species of butterfly or songbird, for example—would ensure you're in compliance. With an intensive roof you should be able to do this.There is a Licensed Professional Exemption (LPE) path available for this credit, by the way.

Nell,

Without substantial documentation from your landscape architect describing the habitat created by sedums and succulants, it is unlikely your roof will meet the credit requirements. Sedums and succulants are mostly low-lying plants (inherantly lacking a diversity of plant size) and they are not known for their habitat providing charactistics.

This requirement comes from the LEED for New Construction Rating System. A LEED-NC CIR from 2007 provides more information around this issue:

9/7/2007 - Credit Interpretation Request
This inquiry is about the accepted non-native sedum based plant mix that will meet credit requirements for green roof system. The facility is located in Boston MA area, USDA Plant Hardiness Zone 6a. Native New England is heavily forested, relatively damp and contains soil with high organic content. A roof top in New England is in full sun, windy, dry and includes mostly inorganic lightweight minerals for soil media with relatively low organic content. Based on this most native species will not survive the rooftop environment without significant levels of maintenance including regular watering and fertilization.

The sedums, succulents and other hardy plants that compose traditional green roof plant palettes are ideally suited for the New England rooftop climate. They would be the lowest maintenance for a green roof system, requiring no permanent irrigation, limited fertilization (annual slow release only), no herbicide or pesticide treatments and overall minimal attention from humans.

The green roof system we are asking for acceptance on is:
Primary - system
15% Sedum spurium, Dragon's Blood
15% sedum kamtschaticum var., floriferum, Weihenstephaner Gold
15% Sedum album, Murale
15% Sedum ternatum, (North American native)
10% Sedum oreganum, (North American native)
10% Sedum rupestre, Angelina
10% Sedum spurium, John Creech
10% Sedum kamtschaticum
Secondary - system - 25% of the primary palette to be replaced with mix of at least two of the following:
Allium schoenoprasum (North American native)
Opuntia humifusa (North American native)
Sedum cauticola, cauticola Lidakense or cauticola Betram Anderson
Sedum reflexum
Sedum spurium Tricolor

10/25/2007 - Ruling
The project is inquiring about the acceptability of a non-native plant mix for their vegetated roof. While the stated plant list (predominantly varieties of sedum) meets the definition of native/adaptive, it does not meet the SS Credit 5.1 intent of providing habitat and promoting biodiversity.

While a number of sedum varieties are proposed, the planting is still essentially a monoculture of species similar in size and lacking in habitat value.