By: Susan Albert, Freelance Garden Writer
plants produce large, elegant flowers in spring, mid-summer, and some
varieties produce a second bloom in the fall. Colors include white, pink, red,
purple, blue, yellow and bicolor. The main types are bearded, beardless,
crested and bulb. Easy to grow and practically maintenance-free, irises are a
favorite of beginning gardeners and a staple in many yards.
The most widespread disease of irises is mosaic virus, mild
and severe, mostly affecting bulbous irises such as Dutch, Spanish and Morocco
types. Spread by aphids, the best deterrent is controlling
aphids in the yard and the weeds that may harbor them.
Iris Mosaic Symptoms
Iris Mild Mosaic Virus exhibits symptoms such as light-green
mosaic-like streaks on new leaves which become more apparent as the plant
matures. The flower stalk and bud sheath may show more mottling. Many irises
can withstand the disease and may not even show symptoms. Other infected irises
may show symptoms one season, but not the next.
Iris Severe Mosaic Virus may cause mild to severe stunting
of iris stems; wide, pale green stripes; or dark teardrop markings in the
flowers of white, lavender and blue cultivars. Yellow flowers may exhibit
feather-like markings. Flower quality is reduced bearing smaller flowers which
often are twisted to one side.
Iris Mosaic Control
Iris mosaic virus is transmitted by aphids, a sucking
insect, as they move from plant to plant ingesting juices. The best control of
the virus is vigilance for aphids and taking measures to reduce or eliminate
them from the garden.
How to Treat Iris Mosaic Disease
- Examine irises for mosaic virus in early spring, mid-spring, while flowering, and end of season. Dig and dispose of severely affected iris.
- Spray aphids with insecticidal soap as soon as they are noticed. Repeat regularly.
- Purchase large, healthy bulbs and rhizomes from reputable growers.
- Reduce weeds in and around iris beds. Weeds can provide a home for aphids and viruses.
While mosaic virus infects bulbous irises predominantly,
rhizomatous irises such as tall bearded irises are occasionally affected, and
the disease also has presented in crocus.
This article was last updated on
“Iris Mosaic Control: How To Treat Mosaic Disease Of Iris Flowers” was first posted here