Bulbs are the generic descriptive term used for most of the rhizome, corm and tuber families. And while we lump them all in the one “family” it makes it hard for novice gardeners to distinguish between the differing ways to treat them. Irises are one of these suffering an identity crisis.

The Delicious Bearded Iris

The bearded iris is a rhizome. Its root grows at a predominantly horizontal level half above the surface of the ground and half below it with the foliage sprouting at each node.

Varieties of Bearded Iris

There are three varieties of bearded iris; the tall bearded iris, the dwarf bearded iris and an intermediate bearded iris that (you guessed correctly) grows in between these two sizes. The intermediate bearded iris is a cross between the dwarf and the tall varieties and is sterile. Therefore, you can only grow off the crossed parent rhizome.

The tall bearded iris is the most common one that you’ll find in many gardens. There are more than 300 varieties and their colours covering the whole spectrum; reds, yellows, whites, blues, purples and even chocolate browns. It is probably the colour choice that makes them so popular as they will work in almost any setting.

For most of the year the green strappy foliage of the bearded iris contrasts well with other plant textures. It’s upright growing habit and stark lines direct the eyes upwards and can highlight larger shrubs or ornaments behind them. They can grow up to 1m (3ft) tall while the dwarf varieties will only reach about 15-20cm (6in) tall.

Once spring comes around the bearded iris will bloom showing off its ruffled flowers and brilliant colours. Planted en masse this is a sight to behold. The trick for young players here is that if you are already trying to develop colour themes within your garden grow bearded irises that will fit in with that scheme. If the garden style is vibrant and can handle a lot of colour then mix them up.

Problems with the Tall Bearded Iris

• Bearded irises, like all plants, can suffer and they usually illustrate their problems with symptoms such as poor flowering. If this is the case it can be attributed to a few different reasons.
  1. Possibly too much fertiliser
  2. If the rhizome is too deep in the soil it may limit its flowering ability
  3. Overcrowding of iris rhizomes will also halt the blooms. If this is the case then you will need to divide the rhizomes and replant after flowering.
• Rhizome rot is another problem that bearded irises suffer from. If the rhizome becomes mushy and smell’s similar to a rotten potato then you will know that your irises are affected. Cut the leaves off and allow the rhizome to dry out in a cool airy room before replanting. You may need to spray with a fungicide before drying.
• Aphids can be a pest to the bearded iris but there is a greater threat from the iris borer, a caterpillar that feasts on the rhizome during the summer months. The best way to control them organically is through the introduction of nematodes, a microscopic worm. These can be purchased through most gardening or nursery catalogues.

Photo source: gelzerman