Changes

Selection of plant species suited to tolerate the varied conditions common to green infrastructure is essential for the success of a planting plan. A plant’s ability to tolerate flood conditions is further correlated to its age, adaptation to the site, and condition. A well-established plant has greater reserves to withstand flood events. While it is recommended to leave the LID practice offline until plants become established (one to several years), in most instances this may not feasible. Measures incorporated into the LID practice such as erosion and sediment controls and pre-treatment cells can moderate flows enhancing survival potential. In all cases, soil surfaces must be stabilized prior to allowing flow to enter the LID facility.

Selection of plant species suited to tolerate the varied conditions common to green infrastructure is essential for the success of a planting plan. A plant’s ability to tolerate flood conditions is further correlated to its age, adaptation to the site, and condition. A well-established plant has greater reserves to withstand flood events. While it is recommended to leave the LID practice offline until plants become established (one to several years), in most instances this may not feasible. Measures incorporated into the LID practice such as erosion and sediment controls and pre-treatment cells can moderate flows enhancing survival potential. In all cases, soil surfaces must be stabilized prior to allowing flow to enter the LID facility.

==Native, Introduced and Rare Plants==

==Native, Introduced and Rare Plants==

The goal of planting design for LID practices is to achieve a sustainable vegetation community that is tailored to the ecological qualities of the site and the aesthetic considerations of the landowner. Plant selection for LID practices is predicated on the principle of ‘right plant for the right place'. Many LID practices are carried out within a highly urbanized context that poses unnatural stresses on plant growth and survival. This guide provides general recommendations to direct species selection. Landscape professionals should use this information to generate specific plant lists that are tailored to the conditions prevalent on site while addressing surrounding urban and natural land uses.  

The goal of planting design for LID practices is to achieve a sustainable vegetation community that is tailored to the ecological qualities of the site and the aesthetic considerations of the landowner. Plant selection for LID practices is predicated on the principle of ‘right plant for the right place'. Many LID practices are carried out within a highly urbanized context that poses unnatural stresses on plant growth and survival. This guide provides general recommendations to direct species selection. Landscape professionals should use this information to generate specific plant lists that are tailored to the conditions prevalent on site while addressing surrounding urban and natural land uses.  

===Native and Introduced Species===

===Native and Introduced Species===

Native plants have co-evolved with the local ecosystems and natural processes. They are genetically better adapted to local climate, soils, insects and diseases of the area, and may require less maintenance to ensure health and survival. Working with native plants helps protect local native biodiversity, allows the LID feature to function ecologically while creating a more diverse, naturally-beautiful, landscape.   

Native plants have co-evolved with the local ecosystems and natural processes. They are genetically better adapted to local climate, soils, insects and diseases of the area, and may require less maintenance to ensure health and survival. Working with native plants helps protect local native biodiversity, allows the LID feature to function ecologically while creating a more diverse, naturally-beautiful, landscape.   

Where conditions for growing native plants are inhospitable, diversifying the planting palate with introduced species may have a more successful result. In addition to native species, many introduced plants are grown in nurseries and garden centers and are readily available to landowners.  

Where conditions for growing native plants are inhospitable, diversifying the planting palate with introduced species may have a more successful result. In addition to native species, many introduced plants are grown in nurseries and garden centers and are readily available to landowners.  

===Rare Species===

===Rare Species===

Some of the native plants in the LID plant list are ‘rare’ and/or ‘uncommon’ within the Region of Peel / Credit River watershed, the Greater Toronto Area  and/or the Province of Ontario . CVC and the TRCA do not support the incorporation of rare native species in planting plans and designs unless locally sourced material can be obtained and there is little to no threat of escape into naturally occurring populations. Genes from plants adapted to other areas can inadvertently introduce harmful traits that weaken the ability of the native population to thrive. Rare species are not always appropriate for LID practices depending on the project objectives or the characteristics of the site, especially in situations where rare species may be planted near natural communities. In these situations, the opportunity for genetic contamination of native populations is higher and the planting of rare species is unadvised.  

Some of the native plants in the LID plant list are ‘rare’ and/or ‘uncommon’ within the Province of Ontario . STEP do not support the incorporation of rare native species in planting plans and designs unless locally sourced material can be obtained and there is little to no threat of escape into naturally occurring populations. Genes from plants adapted to other areas can inadvertently introduce harmful traits that weaken the ability of the native population to thrive. Rare species are not always appropriate for LID practices depending on the project objectives or the characteristics of the site, especially in situations where rare species may be planted near natural communities. In these situations, the opportunity for genetic contamination of native populations is higher and the planting of rare species is unadvised.  

Some native species are rare because they require specific habitat conditions in order to grow which may not exist or be able to be restored easily. The benefits to landscaping with native, common plant material is that plantings may be better adapted to a wider range of conditions, and may tolerate more disturbance. A higher success rate and lower maintenance requirement may be achieved.  

Some native species are rare because they require specific habitat conditions in order to grow which may not exist or be able to be restored easily. The benefits to landscaping with native, common plant material is that plantings may be better adapted to a wider range of conditions, and may tolerate more disturbance. A higher success rate and lower maintenance requirement may be achieved.  

The method and collection of native plants is an important consideration when sourcing rare plant material. Ecologically responsible methods of seed collection and propagation ensure that wild populations are not overharvested and that they have the ability to keep adapting over time. Seeds should not be collected or existing plants relocated from the wild for use in LID practices. When sourcing material from growers and nurseries, the plant material origin should be confirmed as well as its method of collection and propagation.  

The method and collection of native plants is an important consideration when sourcing rare plant material. Ecologically responsible methods of seed collection and propagation ensure that wild populations are not over harvested and that they have the ability to keep adapting over time. Seeds should not be collected or existing plants relocated from the wild for use in LID practices. When sourcing material from growers and nurseries, the plant material origin should be confirmed as well as its method of collection and propagation.  

Recommendation: In areas containing, adjacent  to, or within a linkage to an existing natural heritage feature, common native plants should be used exclusively. In areas regulated by a watershed authority such as the CVC or TRCA, rare species are not suitable for planting unless the local source/provenance is documented and approved. Rare species should only be used sparingly when there are no suitable common species available and reasons for selection should be provided. Where rare species are included in a design, it should be ensured that the plants are procured from locally adapted  seed sources. Biologists, botanists and ecologists can help guide the sourcing and selection of plant material. Nurseries that specialize in native plants should be contacted to source material.

Recommendation: In areas containing, adjacent  to, or within a linkage to an existing natural heritage feature, common native plants should be used exclusively. In areas regulated by a watershed authority

rare species are not suitable for planting unless the local source/provenance is documented and approved. Rare species should only be used sparingly when there are no suitable common species available and reasons for selection should be provided. Where rare species are included in a design, it should be ensured that the plants are procured from locally adapted  seed sources. Biologists, botanists and ecologists can help guide the sourcing and selection of plant material. Nurseries that specialize in native plants should be contacted to source material.

==Natural Processes==

==Natural Processes==

A plant community is not a static entity; rather it is always growing and changing in response to natural processes and disturbance events. When utilizing a plant community as an analogue for design, it is essential to understand the role of agents that affect the composition of the plant community over time. Designers and managers may need to mimic or compensate for the natural processes in a management plan. Consideration should be given for the impact of natural processes and disturbances to the long term vision of the LID landscape design. Natural ecosystems develop and are maintained through natural changes such as the onset of shading, and disturbance events such as:

A plant community is not a static entity; rather it is always growing and changing in response to natural processes and disturbance events. When utilizing a plant community as an analogue for design, it is essential to understand the role of agents that affect the composition of the plant community over time. Designers and managers may need to mimic or compensate for the natural processes in a management plan. Consideration should be given for the impact of natural processes and disturbances to the long term vision of the LID landscape design. Natural ecosystems develop and are maintained through natural changes such as the onset of shading, and disturbance events such as:

*Seasonal storm events / flooding outside the design norms

*Seasonal storm events / flooding outside the design norms