scholarly journals Plants with Horticultural and Ecological Attributes for Green Roofs in a Cool, Dry Climate

HortScience ◽  
2019 ◽  
Vol 54 (10) ◽  
pp. 1703-1711
Author(s):  
John Erwin ◽  
Jonathan Hensley
Keyword(s):  
Plant Species ◽  
Panicum Virgatum ◽  
Green Roof ◽  
Weather Conditions ◽  
Green Roofs ◽  
Dragon’S Blood ◽  
Ecological Attributes ◽  
Koeleria Macrantha ◽  
Cold Hardy ◽  
Well Data

Green roofs are building surface treatments where plants are grown in medium on a rooftop to cool or insulate buildings and/or to ameliorate negative environmental impacts of buildings. We initiated a 2-year study to characterize medium and weather conditions on a rooftop in a cool-dry climate and to identify plant species with horticultural and ecological attributes that survive and thrive on an unirrigated semi-intensive green roof in a cool-dry climate. Eighty-eight cold-hardy, drought-tolerant species with horticultural or ecological attributes were identified and planted into 12.7-cm-deep medium in trays that were placed on a rooftop. Medium temperatures and moistures were recorded, and plant survival and vigor were quantified. Hourly medium temperatures varied from –22.3 to 43 °C. Monthly medium water moistures varied from –2.5 to –73.3 kPa from May to September, and from –7.6 to –195 kPa from October to April. Monthly air temperature, relative humidity and irradiance varied from –9.4 to 21.7 °C, 44% to 80%, and from 206 to 1222 μmol·m−2·s−1. Mean survival scores decreased (4 = 100% survival) from 2.6 with grasses, to 2.3 with succulents, to 1.8 with temperate perennials, to 0 for geophytes (all died). Among grasses, Festuca ovina VNS, Koeleria macrantha 07-901 ND, Panicum virgatum, and Sporobolus heterolepis performed well. Among succulents, Sedum acre, S. album ‘Coral Carpet’, S. cauticola ‘Sunset Cloud’, S. ‘Czar’s Gold’, S. ellecombianum, S. hybridum ‘Immergruchen’, S. requieni, S. sexangulare, S. spurium ‘Dragon’s Blood’, ‘John Creech’, ‘Pearly Pink’, ‘Ruby Mantle’, and ‘Tricolor’ performed well. Among temperature nonsucculent perennials, Allium ceranum and senescens ‘Glaucum’, Geum triflorum, Talinum calycinum, and Thymus praecox ‘Red Creeping’ performed well. Data on Sedum suggested that medium-low temperature was more limiting to survival than moisture level. The differences in species that performed well here, compared with other studies, underscores the importance of regionally specific green roof plant species studies.

scholarly journals Growth of Native Aromatic Xerophytes in an Extensive Mediterranean Green Roof as Affected by Substrate Type and Depth and Irrigation Frequency

HortScience ◽  
2013 ◽  
Vol 48 (10) ◽  
pp. 1327-1333 ◽  
Author(s):  
Maria Papafotiou ◽  
Niki Pergialioti ◽  
Lamprini Tassoula ◽  
Ioannis Massas ◽  
Georgios Kargas
Keyword(s):  
Plant Growth ◽  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Native Plant ◽  
Substrate Type ◽  
Irrigation Frequency ◽  
Artemisia Absinthium ◽  
Grape Marc ◽  
Local Character

Green roofs could be a way to increase vegetation in the center of old Mediterranean cities. The need for conservation of local character and biodiversity requires the use of native plant species, whereas the deficiency of water, particularly in semiarid regions, requires the use of species with reduced irrigation needs. Moreover, the aged buildings lead to the use of lightweight green roof constructions. Therefore, research was undertaken to investigate the possibility of using three Mediterranean aromatic xerophytes, Artemisia absinthium L., Helichrysum italicum Roth., and H. orientale L., at an extensive green roof in Athens, Greece. Simultaneously, the possibility of using locally produced grape marc compost was investigated. Substrate type and depth and irrigation frequency effects on growth of these species were studied. Rooted cuttings were planted mid-May in plastic containers with a green roof infrastructure fitted (moisture retention and protection of the insulation mat, drainage layer, and filter sheet) and placed on a fully exposed third floor flat roof at the Agricultural University of Athens. Two types of substrates were used, grape marc compost:soil:perlite (2:3:5, v/v) and peat:soil:perlite (2:3:5, v/v, as a control), as well as two substrate depths, 7.5 (shallow) and 15 cm (deep), and two irrigation frequencies, sparse (5 or 7 days in shallow and deep substrate, respectively) and normal (3 or 5 days in shallow and deep substrate, respectively). Increased contents of macroelements, total phosphorus (P) and potassium (K) in particular, were recorded in the compost-amended substrate, whereas both substrates had similar physical properties. Plant growth was recorded from May to October. The deep compost-amended substrate, independent of irrigation frequency, resulted in taller plants with bigger diameter and aboveground dry weight in all species. However, a remarkable result was that shallow compost-amended substrate with sparse irrigation resulted in similar or even bigger plant growth of all plant species compared with deep peat-amended substrate with normal irrigation. Thus, all three species were found suitable for use in Mediterranean extensive or semi-intensive green roofs, whereas the use of grape marc compost in the substrate allowed for less water consumption and the reduction of substrate depth without restriction of plant growth at the establishment phase and the first period of drought.

The effect of drainage height on plant-species composition on a semi-arid green roof system

2021 ◽  
Vol 67 (3-4) ◽  
pp. 149-155
Author(s):  
Har'el Agra ◽  
Hadar Shalom ◽  
Omar Bawab ◽  
Gyongyver J. Kadas ◽  
Leon Blaustein
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Plant Diversity ◽  
Urban Areas ◽  
Green Roof ◽  
Growing Season ◽  
Green Roofs ◽  
Plant Species Composition ◽  
Roof System ◽  
Semi Arid

Abstract Green roofs are expected to contribute to higher biodiversity in urban surroundings. Typically, green roofs have been designed with low plant diversity. However, plant diversity can be enhanced by controlling resource availability and creating distinct niches. Here we hypothesize that by using different drainage heights during the short plant-growing season in a semi-arid green roof system we can create distinct niches and plant communities. Our experiment took place at the University of Haifa, north Israel. We tested three different heights of drainage outlet: 10 cm under the surface of the substrate (Low), 1 cm under the surface of the substrate (Medium) and 3 cm above the surface of the substrate (High) on plant species-composition in green-roof gardens. Grasses cover was higher in High and Medium drainages while forbs cover was higher in Low drainage. Species richness was the highest in Low drainage while diversity indices showed the opposite trend. We conclude that by changing the height of the drainage we can create different niches and change species composition in a short time period of one growing season. This way we can create more diverse green roof communities and enhance biodiversity in urban areas, particularly in semi-arid regions.

scholarly journals Evaluating Fertilizer Influence on Overwintering Survival and Growth of Sedum Species in a Fall-installed Green Roof

HortScience ◽  
2012 ◽  
Vol 47 (12) ◽  
pp. 1775-1781 ◽  
Author(s):  
Mary Jane Clark ◽  
Youbin Zheng
Keyword(s):  
Controlled Release ◽  
Green Roof ◽  
Weather Conditions ◽  
Green Roofs ◽  
Visual Appearance ◽  
K Fertilizer ◽  
Overwintering Survival ◽  
Substrate Fertility ◽  
Fertilizer Rates ◽  
Leaf Greenness

Vegetation success on green roofs in northern climates is challenged by extreme weather conditions, especially in winter, and is influenced by season of installation and substrate fertility. Appropriate fertilization with phosphorus (P) and potassium (K) can reduce winter injury for some plant species. The objectives of this study were to identify both the effect of P and K fertilizer rates on Sedum spp. survival over the first winter and the response of Sedum spp. growth to fertilizer rates when applied at installation. In a fall-installed extensive green roof system, survival, growth, and visual appearance of Sedum mats in non-fertilized plots (control) were compared with plots fertilized with 16–6–13 POLYON® Homogenous NPK plus Minors 3-4 month controlled-release fertilizer at 20.0 g nitrogen (N)/m2 either alone or with additional P to total 28.8, 54.4, or 80.0 g P/m2 or K to total 32.5, 51.6, or 70.6 g K/m2. Sedum mats were installed on 8 Oct. 2010 and plants in all plots survived the winter and the next year. During the 2011 growing season, vegetative coverage was not significantly different among any individual fertilized treatments; however, vegetative coverage data combined for all fertilized treatments was larger than the control. Fertilized treatments also showed larger plant height and biomass after one year, taller S. acre and S. sexangulare inflorescences, increased leaf greenness, and higher visual appearance rankings compared with the control. For individual Sedum species, S. album showed the greatest coverage in P-fertilized treatments, and effects on S. acre and S. sexangulare were treatment-dependent. Application of a controlled-release N–P–K fertilizer, without additional P or K, can be used to encourage vegetative coverage, plant growth, leaf greenness, inflorescence height, and visual appearance in fall-installed extensive Sedum green roof systems.

scholarly journals Green Roof Plant Suitability Analysis for Northern Climates

2013 ◽  
Vol 23 (5) ◽  
pp. 563-574 ◽  
Author(s):  
Katherine L. Vinson ◽  
Youbin Zheng
Keyword(s):  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Plant Production ◽  
Suitability Analysis ◽  
Production Growth ◽  
Diverse Plant Species ◽  
Extensive Green Roofs ◽  
Different Levels ◽  
Diverse Plant

To select plant species and species combinations for northern climates, mats with different plant species and species combinations were constructed on a green roof plant production farm and later transported and installed on an urban rooftop. There were three treatments: two different planting combinations, which together consisted of 10 diverse plant species [both stonecrop (Sedum) species and nonstonecrop species], and a control, which consisted of 26 stonecrop species used for standard mat production. Growth measurements and observations were made at both sites and special attention was paid to the performance of species during the harvest, transportation, and installation stages, as well as during recovery postinstallation. All species but false rock cress (Aubrieta cultorum) were found to be suitable for extensive green roof applications in northern climates, although there were variations of suitability among the species. Good, mediocre, and poor interactions formed between numerous species, displaying different levels of compatibility. Finally, all species were considered appropriate for a mat production system; species that failed to germinate, species planted postinstallation, the frequently displaced rolling hens and chicks (Jovibarba sobolifera), and false rock cress were exceptions. Overall, many species in this study displayed successful, well-rounded growth. Based on results, species and species combinations were recommended for extensive green roofs in northern climates.

scholarly journals Irrigation Lowers Substrate Temperature and Enhances Survival of Plants on Green Roofs in the Southeastern United States

2011 ◽  
Vol 21 (5) ◽  
pp. 586-592 ◽  
Author(s):  
Julie Guckenberger Price ◽  
Stephen A. Watts ◽  
Amy N. Wright ◽  
Robert W. Peters ◽  
Jason T. Kirby
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Green Roof ◽  
Empirical Evaluation ◽  
Green Roofs ◽  
The United States ◽  
Environmental Benefits ◽  
Plant Selection ◽  
Soil Temperatures ◽  
Cold Hardy

Green roofs are becoming increasingly prevalent in the United States due to their economical and environmental benefits as compared with conventional roofs. Plant selection for green roofs in the variable climate of the southeastern United States has not been well evaluated. Shallow substrates on green roofs provide less moderation of temperature and soil moisture than deeper soils in traditional landscapes, necessitating empirical evaluation in green roof environments to make informed recommendations for green roof plant selection. Nineteen species and cultivars, including succulents, grasses, and forbs, were evaluated under seasonal irrigated and non-irrigated conditions in experimental green roofs. Plants were planted on 26 Oct. 2009 and each evaluated for survival and increase in two-dimensional coverage of the substrate during establishment, after overwintering, and after the first growing season. The winter 2009–10 was colder than normal, and some plants, such as ice plants (Delosperma spp.), considered to be cold-hardy in this climate did not survive through the winter. Irrigation influenced survival for the summer period and only succulent plants like stonecrops (Sedum spp.) survived without irrigation. Irrigated experimental green roofs had significantly lower summer substrate temperatures (up to 20 °F lower) and plants survived in irrigated conditions. Plants that survived both winter and summer under irrigated conditions include pussytoes (Antennaria plantaginifolia), mouse-ear tickseed (Coreopsis auriculata), eastern bottlebrush grass (Elymus hystrix), glade cleft phlox (Phlox bifida stellaria), and eggleston's violet (Viola egglestonii). Irrigation is recommended on extensive green roofs to increase the palette for plant selection by protecting against plant mortality due to drought and extreme soil temperatures.

scholarly journals The native - exotic plant choice in green roof design: using a multicriteria decision framework to foster urban biodiversity

2022 ◽  
Author(s):  
Ana A. Calvino ◽  
Julia Tavella ◽  
Hernan M. Beccacece ◽  
Elizabet Estallo ◽  
Diego Fabian ◽  
...  
Keyword(s):  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Exotic Plant ◽  
Beneficial Arthropods ◽  
Decision Framework ◽  
Exotic Plant Species ◽  
Multicriteria Decision ◽  
One Year ◽  
Roof Design

Green roofs are considered key elements of the urban green infrastructure since they offer several environmental benefits, including habitat provision for arthropods. To achieve these benefits and ensure green roof success, an appropriate plant selection is an important step in the design of these infrastructures, especially where green roof technology is emerging like in South American cities. So far, decisions of using native or exotic plant species in green roofs had never been evaluated taking into account the plant potential to foster beneficial arthropods. By applying an integrative multicriteria decision framework that combined the habitat template hypothesis with the potential of plants to attract floral visitors and natural enemies, we obtained a ranked set of candidate native and exotic plant species. Among the best-ranked candidate species, we further compared the performance of six native and six exotic species in 30 experimental green roofs installed in Cordoba city, Argentina. To evaluate plant success, the occurrence and cover of each species were recorded one year after establishment under two management conditions: regular watering and weeding of spontaneous plants, and no management (15 roofs each). All selected species increased their vegetative cover one year after establishment. More interestingly, native plants had an advantage over exotic plant species as they exhibited a significantly higher occurrence and a slightly higher cover with no management than exotics. Native annuals were able to reseed the following season even in the absence of management, thus highlighting the relative importance of lifespan as a useful plant trait for future studies in green roof design. Given that green roofs are one of the possible solutions to ameliorate the negative effects of urban habitat loss on arthropod diversity, the development of an integrative multicriteria decision framework that takes into account the potential of native and exotic plant species for promoting beneficial arthropods would give a new twist in plant selection processes for green roofs.

scholarly journals Growing substrates for aromatic plant species in green roofs and water runoff quality: pilot experiments in a Mediterranean climate

2017 ◽  
Vol 76 (5) ◽  
pp. 1081-1089 ◽  
Author(s):  
Cristina M. Monteiro ◽  
Cristina S. C. Calheiros ◽  
Paulo Palha ◽  
Paula M. L. Castro
Keyword(s):  
Organic Matter ◽  
Plant Species ◽  
Urban Areas ◽  
Mediterranean Climate ◽  
Green Roof ◽  
Oxygen Demand ◽  
Green Roofs ◽  
Water Runoff ◽  
Aromatic Plant ◽  
Runoff Quality

Green roof technology has evolved in recent years as a potential solution to promote vegetation in urban areas. Green roof studies for Mediterranean climates, where extended drought periods in summer contrast with cold and rainy periods in winter, are still scarce. The present research study assesses the use of substrates with different compositions for the growth of six aromatic plant species – Lavandula dentata, Pelargonium odoratissimum, Helichrysum italicum, Satureja montana, Thymus caespititius and T. pseudolanuginosus, during a 2-year period, and the monitoring of water runoff quality. Growing substrates encompassed expanded clay and granulated cork, in combination with organic matter and crushed eggshell. These combinations were adequate for the establishment of all aromatic plants, allowing their propagation in the extensive system located on the 5th storey. The substrate composed of 70% expanded clay and 30% organic matter was the most suitable, and crushed eggshell incorporation improved the initial plant establishment. Water runoff quality parameters – turbidity, pH, conductivity, NH4+, NO3−, PO43- and chemical oxygen demand – showed that it could be reused for non-potable uses in buildings. The present study shows that selected aromatic plant species could be successfully used in green roofs in a Mediterranean climate.

scholarly journals MEDIA COMPOSITION INFLUENCES GREEN ROOF PLANT VIABILITY IN THE OZARK HIGHLANDS

2012 ◽  
Vol 7 (4) ◽  
pp. 73-84
Author(s):  
D. C. Toland ◽  
C. P. West ◽  
M. E. Boyer
Keyword(s):  
Plant Species ◽  
Climatic Factors ◽  
Green Roof ◽  
Green Roofs ◽  
Roof System ◽  
Ozark Highlands ◽  
Rooting Medium ◽  
Growing Medium ◽  
Critical Components ◽  
The University

Plant selection and establishment are critical components for green roof health and success. Plant palettes (sets of plant species selected for specific conditions) for green roofs vary in their ability to confer benefits depending on the species make-up and their adaptation to particular environments and climates. The response of various species to climatic factors on rooftops is unknown for the Ozark Highlands region. The objective of this study was to compare plant survival and spread in three growing medium treatments (course and fine texture with compost and fine texture with no compost) installed as part of a green roof system. The study was performed on a green roof system at the University of Arkansas in Fayetteville over 3 years. Data were collected on 13 species installed in September of 2006 and surveyed on three dates thereafter: April 30, 2007; May 19, 2009; September 10, 2009. The treatments with added compost had statistically greater vegetated cover (from 73 to 87%) compared to the fine medium without compost (36 to 43%). In most cases the spread of individual plants was not significantly different between treatments. Results indicated that rooting medium containing compost increased survival and overall vegetated roof coverage, and identified various potential green roof plant species for the Ozark Highland environment. Two species, Sedum middendorffianum var. diffusum and Sedum spurium ‘Roseum’, did particularly well in all treatments. One species, Sedum kamtschaticum, did well only in the treatments with compost.

scholarly journals Moisture Content of Extensive Green Roof Substrate and Growth Response of 15 Temperate Plant Species during Dry Down

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 518-522 ◽  
Author(s):  
Jennifer M. Bousselot ◽  
James E. Klett ◽  
Ronda D. Koski
Keyword(s):  
Moisture Content ◽  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Extensive Green Roof ◽  
Dry Down ◽  
Porous Soils ◽  
Extensive Green Roofs

Success of extensive green roof vegetation depends primarily on associated plant species' ability to survive the low moisture content of the substrate. As a result of the well-drained nature of the substrate, plants adaptable to dry, porous soils are primarily used in extensive green roof applications. Although Sedum species have dominated the plant palette for extensive green roofs, there is growing interest in expanding the plant list for extensive green roof systems. To effectively select suitable plants, species need to be evaluated in terms of their response to gradual and prolonged dry down of the substrate. A study to determine the relative rates of dry down for 15 species was conducted in greenhouse trials. During dry downs that extended over 5 months, the substrate of succulent and herbaceous species dried down at different rates. The change in moisture content of the substrate was not consistent among succulent and herbaceous plant species during the initial 18 d of dry down. Despite differences in rate of dry down, the succulent species, as a group, maintained viable foliage for over five times longer than the herbaceous species. The revival rates of the succulent species were nearly double those of the herbaceous species. Therefore, not only are succulent species more likely to survive during periods of drought, but these species are more likely to resume growth soon after water is again made available.

scholarly journals Stormwater Retention and Reuse at the Residential Plot Level—Green Roof Experiment and Water Balance Computations for Long-Term Use in Cyprus

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1055 ◽  
Author(s):  
Katerina Charalambous ◽  
Adriana Bruggeman ◽  
Marinos Eliades ◽  
Corrado Camera ◽  
Loukia Vassiliou
Keyword(s):  
Water Balance ◽  
Plant Species ◽  
Rainwater Harvesting ◽  
Green Roof ◽  
Irrigation Treatment ◽  
Stormwater Runoff ◽  
Green Roofs ◽  
Roof Experiment ◽  
Stormwater Retention

Green roofs can provide various benefits to urban areas, including stormwater retention. However, semi-arid regions are a challenging environment for green roofs as long dry weather periods are met with short but intense rainfall events. This requires green roofs to retain maximum volumes of stormwater, while being tolerant to minimal irrigation supplies. The objectives of this study are (i) to quantify the stormwater retention of two substrate mixtures with two plant species under natural rainfall; (ii) to assess the performance of two plant species under two levels of deficit irrigation; and (iii) to compute stormwater runoff reduction and reuse by green roofs and rooftop water harvesting systems for three standard residential plot types in urban Nicosia, Cyprus. A rooftop experiment was carried out between February 2016 and April 2017 and results were used to compute long-term performance. Average stormwater retention of the 16 test beds was 77% of the 371-mm rainfall. A survival rate of 88% was recorded for Euphorbia veneris and 20% for Frankenia laevis, for a 30% evapotranspiration irrigation treatment. A combination of a green roof, rainwater harvesting system and 20-m3 tank for irrigation and indoor greywater use reduced stormwater runoff by 47–53%, for the 30-year water balance computations.

Sign in / Sign up

Export Citation Format

Share Document