This photo from the Island Garden depicts three of the finest perennials with elegant silver foliage in the winter landscape. They are growing in the living wall: Santolina Santolina chamaecyparissus (foreground), Silver Frost Lavender Lavandula 'Silver Frost' (middle plant) and Dwarf Horehound Ballota pseudocictamnus 'Nana' behind. Each has a different subtle shade and unique texture so they create quite a pleasant composition when grown together. All need full sun and good drainage! Our most successful santolinas originated from a special zone 5 hardy strain from High Country Gardens http://www.highcountrygardens.com/ in Santa Fe, NM. The Silver Frost Lavender is another specialty plant from High Country Gardens. Dwarf Horehound is more readily available.
Here is a closeup of a young Silver Frost Lavender in the living wall. No other lavender is so silvery!
The rare Partridge Feather or Silver Feather Tansy Tanacetum densum ssp. amanum has some of the most beautifully textured foliage of any plant at Powell Gardens. We trialed it from Siskiyou Rare Plant Nursery http://www.siskiyourareplantnursery.com/ in Talent, Ore. It has been successful in a place of good air circulation in the living wall for years!
The evergreen, needle-like tuft of foliage of Firewitch Dianthus Dianthus gratianopolitanus 'Feuerhexe' make it an outstanding plant when not in bloom. In late spring it is covered with vivid fuchsia flowers. It was Perennial Plant of the Year in 2006 and is now a Plant of Merit for our region.
The silvered, purple leaves of Regina Coralbells Heuchera 'Regina' are some of the best for hardiness and durability! This coralbell has staying power and its "evergreen" leaves are beautifully contrasted when grown among Angelina Sedum Sedum rupestre 'Angelina' as can be seen growing on the Island Garden.
Read the book Elegant Silvers by Jo Ann Gardner and Karen Bussolini (Timber Press 2005) for more ideas with silver plants.
All photos were taken by Alan Branhagen in January 2008 at Powell Gardens.