Green Density for Wall Gardens
Yael Ehrenberg Hellion is the co-founder and principal designer for Verde360, a landscape design firm in San Francisco and Mexico City. In 2007, together with two friends, an architect and an industrial designer, she started her own landscape design and build studio in Mexico City, specializing in vertical gardens. In the last ten years their studio, Verde360, has produced a great number of vertical gardens ranging in sizes from 64 sf to 30,000 sf.
I can say it is a challenge to create a dynamic design with plants of different textures, colors and growth habits in the same artificial environment on a vertical plane. But I have found out that there are plants which spread and grow more easily on a green wall and that are very helpful to use in combination with other accent plants to create "green density" and to fill in spaces on the vertical garden that otherwise would look more sparse. I came up with a list of some of my favorite plants for green walls here in California, many of which I have also used in my projects in Mexico.
Aeschynanthus radicans, LIPSTICK PLANT
Ajuga reptans, CARPET BUGLE
Bergenia cordifolia, HEART-LEAVED BERGENIA
Lamiastrum galeobdolon, 'Florentinum' YELLOW ARCHANGEL
Liriope gigantea, GIANT LILY TURF
Nephrolepis cordifolia, SWORD FERN
Plectranthus verticillatus, SWEDISH BEGONIA
Philodendron scandens, HEART LEAF PHILODENDRON
Philodendron 'Xanadu', SPLIT LEAF PHILODENDRON
Soleirolia soleirolii, BABY'S TEARS
Vinca minor, BLUE PERIWINKLE
This is a great plant for indoor green walls with indirect light. I really like it because it looks very elegant. It is an epiphytic evergreen vine with slender trailing stems and small dark green glossy leaves with clusters of orange-red tubular flowers. It can easily be propagated when doing maintenance on the green wall by inserting the cuttings in other 'pockets'. Photo courtesy of Yael Ehrenberg Hellion
This is an easy spreading groundcover that forms an attractive mass of short bronze tinged leaves adding color to the green wall. It usually looks good throughout the year and is not very delicate. Photo courtesy of Emerisa Gardens.
This herbaceous perennial has large, thick, leathery, evergreen leaves, heart shaped at the base. When grown on a vertical garden the leaves overlap and the highlight is the short stemmed panicle of pink flowers. It is also relatively easy to maintain. Photo courtesy of Emerisa Gardens.
Lamiastrum galeobdolon 'Florentinum'
I like this one very much because it spreads easily creating a carpet of beautiful green silver variegated leaves, bearing small soft-yellow flowers. It is also rugged, hardy and durable. I like to use it in the middle areas of the green walls because the delicate stems can hang down to 3ft long. Photo courtesy of San Marcos Growers.
GIANT LILY TURF
This is one of my favorites because it has a lot of movement with dark evergreen shinny slender grass like leaves. It is a slow grower but once it takes off on the green wall it adds a beautiful textural contrast in combination with bold leafed plants. It looks as if it were ' lustrous long hair'. Photo courtesy of San Marcos Growers.
I personally love ferns and most of them do very well on green walls. This particular one is very easy, it propagates very fast, however it can easily take over but can be controlled by constant maintenance taking away the hairy runners. It has tufts of finely-toothed sword-shaped fronds that rise from short, erect, hairy leaf stems. On the ground the frond grows erect but on a vertical garden the leaves will hang 2-3 feet down. Another Sword Fern that works very well is Polystichum munitum but this one prefers shady conditions. Photo courtesy of San Marcos Growers.
SPLIT LEAF PHILODENDRON
This plant has very attractive evergreen, bold foliage and it is ideal for creating a lush tropical effect on green walls. It adapts easily outdoors and indoors and can tolerate quite cool conditions. This philodendron grows approximately 2 feet out of the vertical garden and looks better on larger green walls. It is also very easy to maintain. Photo courtesy of Village Nurseries.
This is one of the few plants that actually spreads delicately interweaving it's small thin roots in the felt of the green wall as if it were a soft fresh green carpet glued to the textile substrate. It can grow indoors or outdoors and is ideal for planting in between long stemmed plants. Every four to six months it will turn brown and seem to dry out but just by passing the hand and gently rubbing or shaking off the dry minuscule flowers and leaves will help promote fresh green regrowth in a short time. Photo courtesy of Devil Mountain Wholesale Nursery.
Plectranthus verticillatus (Swedish begonia) This plant has aromatic glossy, green, round leaves, which show a deep purple color in the center sometimes and tend to trail. It is a robust plant that does well in indirect sunlight. It responds well to pruning and can even be easily propagated on the same green wall with cuttings that root on the textile substrate. Throughout the year it has very pretty sporadic racemes of small white, pale violet or pale pink flowers.
Philodendron scandens (Heart Leaf Philodendron). Although a common household plant it is very generous and grows very well on indoor green walls even with indirect light. In warmer conditions it grows well outdoors, I have used it in the area of Los Angeles. It spreads fast and can be kept with a thick foliage by pinching the stem after a leaf node. If the plant is happy, greenish-white arum family flowers will appear infrequently on the mature plants.
Vinca minor (Blue Periwinkle). This is a vine that works very well hanging over other plants creating a "translucent curtain effect" because when grown on a vertical plane the trailing stems are very delicate and the small leaves are widely spaced so they do not overpower the plant that is growing below them. The variegated varieties work very well in the more shady parts of the green wall. This plant has also small delicate purple-blue flowers.