If you stripped brush from your slopes this summer to eliminate the fire hazard or just moved into a new home that came with an uncovered bank, anticipate the erosion that winter rains will cause while you still have time to do something about it. For maximum fire and erosion you need to establish as green and lush a groundcover as possible. With a good irrigation system, fertilizer, and suitable plants, you can do it in three months or less. A newly planted slope will not fill in rapidly without adequate water. Therefore, your first priority should be installing a good irrigation system that provides a slow, even distribution of water.
The steepness of your slope will dictate to a large degree what types of plants you should use. If your slope is extremely steep – 45 degrees or close to it – you might consider using jute netting to stabilize the ground while your new plants get a good start. The netting is stapled into place, and then you plant your ground cover throughout the netting. As the plants grow, the net will be covered over and eventually disintegrate.
Disneyland, Rosea, and Red Apple Ice Plant are three of the most efficient groundcovers available, offering the best protection for even the steepest grades and against fire. The Disneyland and Red Apple varieties are more luxuriant, but the Rosea is more drought resistant.
Gazania, with their orange, yellow, and red daisy-like flowers are a good cover for more moderate slopes. They come in clumping or trailing varieties, with the latter the best for larger scale coverage. Mitsua, a type of Gazania that has bright yellow flowers and attractive foliage, is one of our favorites.
Don’t be misled into thinking that true groundcovers are the only plants suitable for banks. Shrubs and trees can add to your groundcover’s ability to hold a slope, while adding some interest in texture and color as well. Low, rambling shrubs like Cape Honeysuckle, with yellow, orange, or red flowers in late summer and fall, or Plumbago, another summer and fall bloomer with blazing blue flowers, are good choices if you want to add some seasonal color. Prostrate Acacia, a very drought tolerant, spreading plant with gray-green leaves is another shrub that does well on banks.
Some smaller trees that don’t require much water and can thrive in relatively poor soil are also alternatives. Look for California Pepper and Brazilian Pepper trees, Toyon, and Ceanothus. Vines are also excellent cover for slopes, especially where fences or rocky terrain make other groundcovers difficult to use. Star Jasmine, Bougainvillea, and Honeysuckle are three of the best bets.
The important thing most people forget when they landscape a slope is fertilizer. Regular use of fertilizer can make all the difference in the world. Generally slope soils are the poorest, but you can encourage vigorous growth by introducing nutrients and organic matter to create good soil chemistry.