How to Grow & Care for African Iris

The African iris (Dietes iridioides) is an evergreen plant that grows well in warmer zones, with a long season of flowering from spring through fall. It can be grown as a perennial in zones 8 to 11, and in colder zones is commonly grown as an annual. This plant thrives in full sunlight (but can bloom in partial shade) and is very drought-tolerant. Read on for our care and growing guide.

African Iris Care

These are the general care requirements for growing African iris:

• Relatively low maintenance
• Benefits from frequent dividing, at least every 2 or 3 years
• Thrives in full sun
• Drought-tolerant

Light

Thought it thrives best in full sunlight, the African iris will bloom in partial sunlight. In partial sunlight blooms may not be as vigorous. Ideally, it should get six hours of sun per day in its blooming season if possible, and afternoon sun is a bit stronger than morning sun for placement of this perennial.

Soil

These plants like a rich, well-drained loamy soil. Many irises are not fussy about soil, but the African iris requires good drainage to keep the rhizomes healthy. If you have clay soil, add some compost or other amendments to improve drainage before planting African iris.

Water

Once established, the African iris is very drought tolerant and doesn't need any special watering. In times of extreme drought it might need to be watered. In its first two years, or right after planting, it should be watered regularly.

Temperature and Humidity

Because they originate in a tropical climate, the African iris is not cold tolerant and will not survive as a perennial in places with harsh winter temperatures. Being very drought tolerant, they may not do too well in areas with high humidity in summer. Dividing them frequently allows air circulation to prevent any issues caused by too much dampness.

Fertilizer

The African iris can benefit from fertilizer during the growing season. Apply a basic all-purpose plant food in spring and midsummer to help promote blooms and keep insects at bay. Apply fertilizer several inches from the plant to prevent burning the roots.

Pruning

The African Iris will tend to bloom quite heavily during the peak of the summer season. Deadheading the blooms will keep your plants looking fresh and lively. You may also trim off any brown or dead or damaged leaves. Clean your tools before cutting the leaves (a good garden habit) to avoid any bacteria that may lead to root or crown rot.

Propagating African Iris

Like other kinds of irises, the African iris has a clumping growth habit and spreads via rhizome, but it also spreads when its seed pods bend down to the ground to form new roots. The best way to propagate is from existing plants after dividing. Here's how:

1. To get the root divisions you will need to divide the plant, or obtain divisions from someone else.
2. Divide as you would similar clumping irises such as Japanese iris: dig them up, shake off excess dirt, and use a sharp knife to cut the roots.
3. Plant in potting medium or well-drained soil. Plant indoors in the fall, or outside after last frost date in spring. Be sure the plant will get at least six hours of direct sunlight per day; eight hours of indirect sunlight may be sufficient. Be sure to water regularly.

How to Grow African Iris From Seed

It's possible to grow African iris from seed. Here's how:

1. Gather seeds from the pods in the fall.
2. Plant seeds indoors in the fall, or after last frost date in spring. The seeds do not need to be soaked or cold stratified.
3. Plant in well-drained soil where there is at least six hours of direct sunlight per day. Water lightly and frequently. Seeds should begin to germinate within four weeks.

Overwintering

In growing zones that are too cold for it to survive the winter, this plant can be grown successfully as an annual. It can be dug up and overwintered and replanted in spring, much like digging up other perennials such as cannas or dahlias that are not cold tolerant. If you plan to dig up your African iris in winter, shake off any extra soil, and allow the rhizomes to dry thoroughly before storing them in peat moss or sand in a cool dry place. They can be replanted in spring when temperatures have warmed up and and danger of frost has passed.

Common Pests & Plant Diseases

Though it is generally low maintenance, there are a few occasional diseases and pests affecting the African iris. The most common involve crown rot or root rot. This tends to occur when the plant remains damp for too long. Prevention is the best way to address this: plant in well-draining soil, divide the plant frequently to keep the roots healthy, and plant in a location with good air circulation. If your plant does develop rot, dig it up, cut off the affected area, and replant. Autumn is a good time to divide and replant them to keep them healthy.

There is also a possibility of fungal and bacterial diseases, including rust, Botrytis blight, and fungal leaf spot. Fungal diseases can be recognized by the appearance of yellow or brown spots on the leaves; left untreated these diseases can spread to the entire plant. In wet, warm weather, bacterial leaf spot may occur; this causes small spongy, wet spots to appear along the leaf margins, and can cause bigger watery lesions to spread. If your African iris shows signs of fungal or bacterial disease, remove all damaged plant parts and allow the plant to dry out well, and avoid overwatering.

Common pests that may affect your African iris include aphids, iris borers, and nematodes. Iris borers attack the plant in their larval stage and can quickly cause widespread damage. This can be prevented with the weekly application of neem oil spray. This will also help prevent aphids. Nematodes (Ditylenchus destructor) may attack the young roots of the plant and cause browning of leaves and wilting of roots. To prevent this, remove any damaged or diseased plant parts and practice good hygiene with clean tools to prevent infection or spread.

How to Get African Iris to Bloom

Bloom Months

Once an African iris is two years old, it will tend to bloom year round. When it is younger, it should bloom consistently throughout the spring and summer. The flowers are somewhat short-lived but there are usually plenty more waiting to bloom as the flowers fade and drop off.

What Do African Iris Flowers Look and Smell Like?

This attractive plant has a round, six-petalled creamy white flower with a smaller four-petalled blue-purple flower that emerges in its center, with bright yellow accents running down the center of the white petals. The flower scent, if noticeable, is subtle yet sweet.

How to Encourage More Blooms

If your African iris isn't blooming consistently, make sure it's getting enough sun. It needs at least five hours of direct sunlight per day. You might also try watering it a bit more often and see if keeping the soil slightly moist helps the plant to form more flower buds. Finally, regular fertilization will also help your plant form more blossoms.

Common Problems With African Iris

African Iris are generally low-maintenance and easy growing, but watch out for yellowing or dropping leaves. If you notice either, it could be due to either too much or too little water. Make sure to test the soil and ensure it's being given the appropriate amount.