The Louisiana Iris
The Louisiana iris comes from the wetlands near the Gulf of Mexico in the USA. Unlike most plants, which go dormant or stand still in the winter, the growth cycle of the Louisiana iris begins in autumn, continues through winter and culminates in a burst of rapid bloom in the spring.
Louisiana irises are easy to grow. They thrive on ample water and an acidic (pH 6.5 or lower), fertile growing medium. The plants may tolerate neutral or slightly alkaline conditions with sufficient water. I use Braaks acid compost mixed with some garden soil when planting in containers and when planting in the open ground add acid compost and some sulphur to the soil to lower the pH.
Louisiana irises are evergreen perennials with sword like leaves which make them excellent landscaping accent plants. They can be grown in typical garden beds, bog gardens or in a water feature. Other than their diversity in terms of the flower shape and height there is a vast range of colours to choose from. White, yellow, blue, purple, red, pink with differing blend and star patterns makes each exquisite flower a gem in the garden.
The best time to plant and divide Louisiana irises is from February to April. Irises should be planted with at least 5 cm of soil covering the rhizome and, ideally, at least 10cm of mulch over the soil. Planted about 75cm apart, these irises can be left in place for 3-4 years and will form large clumps. It is helpful to thin the bed every few years. Transplanting immediately during or after flowering is not recommended. The hot weather following the blooming season will stress the plants and little growth or even an early dormancy may result.
Prepare Louisiana iris beds a few weeks before planting, ideally at the end of February. I use Neutrog Bounce Back or Talborne 2.3.2 when planting my rhizomes, then feed monthly with a general fertilizer until June and then change to Vigorosa 3.1.5 or Talborne SR 3.1.5 from mid July to stimulate the flower production.
Louisiana irises will grow anywhere but seem to prefer a part shade position. In a very hot climate the blooms need some protection from the sun. The mandatory mulch (we use pine needles) helps to retain moisture in the soil, keeps weeds under control, increases organic matter in the soil and protects against sun scald. Louisiana irises also grow well in very cold areas.
It is important to give iris beds a thorough soaking at least once a week, particularly in the growing season from late autumn to spring. Too little water will cause stunted growth, leaves to turn yellow, or even stop growth and cause a plant to go dormant. When planting or replanting new rhizomes, the plant must be given time to establish new roots before giving it too much water. Keep the roots damp for three to four weeks before placing newly potted irises in water beds.
Louisiana irises are not prone to disease or insects. For harmless rust spots, use any good fungicide and remove affected foliage.
These irises provide brilliant displays in the garden and are magnificent cut flowers for floral arrangements. Remember WATER, MULCH AND FEED! They multiply well, so be sure to share a rhizome with a friend! February to April is planting time so order your rhizomes now.
|Leone Williams||012 342 5762|
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