Xeriscape planting in 10cm substrate?
Green-Roof planting is still in the experimental stages. What will work and what will fail?
THe First Five Guinea Pigs
Stonecrop (Sedum spectabile)
The sedums are often used on green roofs, but they are usually the dwarf, creeping species. How will the large sedum spactabile fare with only 10cm of soil? As you can I have left the winter seed heads, which are effective in their own right.
Thrift (Armeria maritima ‘splendens’)
A stalwart of green roof planting. This is one of Britian’s toughest plants surviving on exposed cliff edges in shallow soils. It gradually spreads into an evergreen grass-like carpet, that needs no trimming. The flowers are pale pink – deep pink in the variety ‘Splendens’.
I planted many groups of spring bulbs, including white and purple crocus, blue grape hyacinth, purple Iris reticulata and silver-mauve Allium christophii (just peeping through in this photo). The Iris and Allium like a good roasting in summer to ripen the bulbs
Sedge (Carex oshimensis ‘Evergold’)
This sedge has a cream stripe down the centre of each bright green leaf, making the whole plant light up, especially on dull days. It is surprisingly drought tollerant, and manages well in the harsh environment of the green-roof.
Stonecrop (Sedum spathulifolium ‘Purpureum’)
Varieties of sedum are the commonest species used on green roofs. They are succulent and very drought tolerant. I have planted about fifty plants from the following species: s. acre, s. spathulifolium ‘Capo Blanco’ and ‘Purpureum’, s. reflexum, and s. spurium.
More About the Green Roof
The Green Roof Construction
- Sub-deck structure
- Butyl liner installation
- Drainage detailing
- Growing medium & planting
- Construction drawing
Posts about the Green Roof
The Workshop construction
Learn how the building under the Green Roof was designed and constructed.