By Trish Grenfell, Master Gardeners of Placer County
Q: Last week I drove by a rooftop garden with billows of beautiful yellow daisy-like flowers falling over the top.
Not only was I amazed that someone was growing plants on their carport, but what was this bright yellow flower with bountiful spring-like blooms in late November? When I actually stopped and asked the homeowner, I was told, “Copper Canyon Daisies.” I want it in my garden; please tell me about this beautiful plant.
A: The Copper Canyon Daisy or Tagetes lemmonii, sometimes referred to as the perennial marigold, is a large plant that can reach up to 5 feet with a 4' spread, with very aromatic, airy foliage, and vibrant yellow daisy-like blooms. It can be pruned back to any size you want (it can be leggy looking if you don’t prune), but the pruning must stop by late July to enable the fall blooms. When in full bloom the brilliant yellow-gold flowers will almost smother the plants. These blooms last from late September to the first frost and then the plant dies to the ground in the winter
Beauty isn’t the only benefit of this daisy. Its pungent, mint-smelling foliage will keep the deer away from your garden but hopefully not you. Either you will love or hate its aroma, but you can’t ignore it. This plant also has a very high heat/sun tolerance and is a good choice for hard to landscape areas such as a west facing wall or a high reflective light area. It will survive drought situations, but blooms more with some water. It will grow in poor soils but needs good drainage. It is easily propagated by cuttings and be aware that the Copper Canyon Daisy spreads easily; branch ends that touch the soil will root.
Because this daisy does well in zones 8-10, it should do well in the Auburn and areas to the west but needs more protection in zone 7 (the upper foothills).
The rooftop garden you saw represents a movement to decrease the human footprint on the earth. Green roofs have many benefits: they help moderate temperatures, improve air quality, reduce storm-water runoff and create habitat for birds and butterflies. They can create a green refuge within an urban sea of concrete. Rooftop gardening is an exciting trend in the United States. In Chicago, a citywide program is helping businesses and homeowners to plant gardens on their roofs through tax incentives and technical help. Portland, Seattle, and the state of Maryland also offer tax incentives for creating green roofs. Look for more flowering rooftops in the future.