Garden Roof FAQ

Southern Climates

In the southern part of the country most sedum are not a viable option. While most sedum is not recommended for the south, there are many types of succulents, natives, grasses and perennials that can be used to vegetate your Garden Roof. Please contact Hydrotech for specifics.

Your Garden Roof and Dormancy

A majority of plant life functions best when there is ample water and favorable temperatures. However, with the exception of tropical regions, most plants are exposed to dry periods and/or temperatures below freezing for some period of time during the year. Unlike animals, plants do not have the ability to add insulation through fat stores or a winter coat, nor do they have the ability to relocate. Instead, plants go through a period of dormancy.

Dormancy is a state in which plants exhibit little or no growth and in which most, if not all metabolic activity ceases for a period of time. It is typically triggered by cooler weather and a reduction in sunlight, but also can be brought on by stress due to heat or drought. These changes in climate are nature’s mechanisms to inform the plants that they need to start shutting down for the upcoming winter months. The plant goes into dormancy at this time because it can no longer make enough food from photosynthesis to support active growth.

Nearly all plants in temperate regions go dormant in winter, including those on your Garden Roof. Most deciduous plants, including some sedums, shrubs, and trees, lose their leaves in preparation for dormancy, in order to protect themselves against upcoming damaging weather conditions. With the onset of freezing temperatures, deciduous plants must protect themselves against water freezing and then rupturing their cells.

Evergreen plants also go dormant, but less conspicuously than their deciduous counterparts. While evergreen trees and shrubs do not grow, pollinate, or produce seeds during dormancy, they retain their leaves or needles. This holds true for some species of evergreen sedums, which will hold onto their foliage, but typically take on an orange or reddish color during dormancy.

The onset of dormancy emphasizes the importance of ensuring plants are properly established and healthy heading into the winter months. Ideally, plants within newly installed landscapes have the opportunity to get established for at least a few weeks, and uptake water into their roots and stems and (evergreen) leaves part of their normal processes. This water will prevent the plants from drying out during dormancy. If plants do not have the opportunity to establish and uptake water, they will dry out and are then susceptible to desiccation or winter burn.

Although dormancy can be considered a quiet time for your Garden Roof, many plants provide winter interest throughout the winter months. Evergreen sedums turn orange, red, and brown, ornamental grasses provide color and texture, and woody plants even without their leaves, can provide structure. A plants dormant state and how it can contribute to the aesthetic of your project should be considered when designing your Garden Roof.

Dormancy will come to an end in spring, the weather starts to warm and the days get longer, and plants can resume their normal processes. Spring is typically a great time to check nutrient levels within the media, which should be amended as necessary based on the type of plantings. This will ensure plants have all the vital nutrients for a successful growing season.