The butterfly or African irises consist of several species in the genus Dietes and are used extensively in landscapes and around water gardens. Natives of southern Africa, these plants are tolerant of drought conditions and will remain green over the winter, unless temperatures dip below 25 degrees F. Flower spikes bear successive exotic blooms that may last only a day or two. Narrow, sword-like foliage may reach heights of 4 feet under optimal conditions. Maintenance is easy, and pruning is not essential but will enhance the appearance of the plants.
Snip back any winter-damaged foliage in the early spring, before new growth emerges. Make clean pruning cuts straight across the foliage blade at the crown of the plant.
Trim away any foliage that is in decline during the growing season.
Deadhead dying blooms or seed heads by pruning just below the flower. Do not remove the flower stalk, as successive blooms are produced on the same stalk. However, when the flower stalk begins to decline, prune it back to the crown.
Divide oversized or crowded clumps of plants in the late winter, before spring growth begins.