Irises come in every single colour of the rainbow and their heights range from a few inches tall to up to five feet so they can be planted anywhere in the garden – from the back areas to the front borders. They’re relatively inexpensive and will multiply so you can divide and transplant them elsewhere in your garden or share them with friends in a few years.
Iris care is minimal once the growing iris is established. Iris plant care consists mainly of dividing the iris plants to assure continued blooms. Iris plants are abundant multipliers but once the rhizomes of iris plants become crowded, the iris flowers may be limited and the rhizomes need to be separated.
PlacementIrises love 5-6 hours of full sun but can also do very well in partially shaded areas if you live in hot places. Plant them on your south-facing windowsill or balconies where they can get good sun. Even west-facing areas are great for irises.
Water thoroughly when the top two inches of the soil becomes dry to the touch till the water drains out of the drainage hole at the bottom and always drains the bottom plate to avoid overwatering. The more light and warmth the iris gets, the more frequently it will need to be watered.
When watering an extremely dried out soil (visible cracks and soil leaving the planter walls) water in batches. Watering all at once allows the water to simply pass through the soil without getting absorbed.
Every time a plant is watered, water it thoroughly till you see some draining out of the drainage hole and always empty the underplate.
SoilIrises require a full sun location in well-draining soil with an ideal pH of 6.8. Rhizomes can be planted any time after flowering, from mid-summer to early autumn.
Before planting, soil should be loosened with a garden fork to a depth of 12 to 16 inches, with compost mixed into the top six inches. To improve drainage, mix in coarse sand or perlite. To plant, dig a hole a few inches longer than the rhizomes and about four inches deep, and mix in a few spoons of bone meal per rhizome.
Pile some loose soil into a ridge four inches high down the middle of the planting hole. Place the rhizome on top of the ridge, laying the roots down on both sides. Fill the hole, covering the roots but leaving the top of the rhizome exposed and press the soil to compact it and water it deeply.
Apply a low nitrogen or balanced fertilizer like Ugaoo Plant tonic in early spring and once again after flowering. Always add compost at the time of potting and top of the topsoil with a handful of compost every 30 days.
PruningDeadhead seed pods from the plants to prevent beds from becoming overcrowded with seedlings. After flowering, cut back the flower stalks and trim any brown tips if needed, but preserve the leaves.
PropagationThe best way to propagate iris is by rhizome division. However, propagating species plants from seed is also an option, although the germination rate can be as low as 50 percent and it can take two to three years for flowers to appear. Over time rhizomes can become crowded which can inhibit flowering, and clumps should be divided every three to five years. To create new plants, divide roots approximately six to eight weeks after flowering, or mid to late summer.
- Give plants a sunny spot in well-draining soil.
- Provide ample spacing when planting tall, bearded varieties as they need good air circulation.
- Use a light touch with mulch and ensure rhizome tops are exposed to the sun.
- Cut back foliage in fall to deter overwintering pests.
- Aphids are small green or grey insects that suck sap from the leaves and also spread disease from plant to plant.
- Snails and slugs are also known to munch on leaves and flowers, creating irregular holes.
- Soft rot occurs during warm, wet springs, and symptoms include soft, smelly rhizomes, and decay at the base of leaves.