Study of herbaceous annual and perennial species native to Mediterranean area for landscape purposes

Soils characterized by low fertility, the absence of structure, low organic matter content, and a high content of alien materials can be valuable for the creation of species-rich vegetation communities. In fact such communities are often associated with low fertility soils, especially regarding nitrogen levels. Very few studies have been carried out in southern Europe on the cultivation techniques of native herbaceous species and on how to create and maintain semi-natural herbaceous communities in relation to soil properties. This study is aimed at determining the ecological characteristics and the cultivation needs of 26 herbaceous species native to Italy and southern Europe in order to identify their landscape potential in low-maintenance conditions. Mono-specific plots were set up in three different soils. The criteria for choosing the species were based on their capacity to thrive in poor dry soils and to tolerate stress and disturbance. In addition the criteria were also based on their ornamental value, including the ability to attract insects. Annuals, biennials and perennials were included in the study. Seedling emergence and plant biomass were determined. The percentage of field establishment and biomass appeared to be affected by the physical and chemical characteristics of the soil. Species were classified as having low or medium-high seedling emergence in the field assessment. Calamintha nepeta, Campanula rapunculus, Dianthus carthusianorum, Verbascum blattaria, Nigella damascena, Salvia verbenaca, and Scabiosa columbaria developed low biomass. Thus they were more suitable for long lasting plantings in unfertile soils (e.g. land restoration). Daucus carota, Matricaria chamomilla, Papaver rhoeas, Verbascum sinuatum, Coleostophus myconis and Senecio erraticus produced high biomass especially in the most fertile soil. They are more likely to survive competition in highly productive soils.