Knock Out Rose Disease

Rose Rosette Disease: Dallas Is the Epicenter

Rose Rosette Disease called RRD and Knockout Rose Disease manifests itself with elongated and bright red branching. Knock Out roses and Drift roses are especially susceptible. RRD began appearing in about 2009 in Dallas.

Knockout Rose Disease Elongated red branches contain microscopic mites

Elongated red branches known as “Witches Brooms” contain microscopic mites.

You will see the pointed, elongated growth as shown above this is often referred to as “witch’s broom.” Your Knock Out rose will have more thorns; its buds, leaves and flowers will be distorted. The rose will be become more susceptible to mildew and black spot and generally die in two to five years. Younger, smaller roses die sooner than older more established roses.

RRD Knock Out rose disease contain microscopic mites

Elongated Red Branches Contain Microscopic Mites

The Rose Rosette disease is a virus carried on the wind by a winglesss mite, the eriophyid mite. Mass plantings are generally all infected. There is no treatment. The rose will be infected in May though may not be symptomic for a few months thereafter. The mites can survive a winter in the live canes and even in the roots. When you remove the foliage you remove the mites.

Because the virus is present in roots the rose really has no chance of survival. Remove the root ball of infected plants and destroy sprouts of any roots not eliminated if they develop because they will contain the virus as well.

Knock Out Rose Disease is a common name for Rose Rosette Disease.However, the cure suggested is to remove any infected plant completely. It contains the damaging mites. It has been noted that removing the damaged part of the plant often encourages the mites living within the plant to simply move lower.

The Pennsylvania nursery that introduced ‘Knockout’ roses has suggested that you prune the roses back by 2/3rds while they’re dormant in late winter to remove any overwintering mites and eggs in the bud crevices.

June Pocket Perennial Garden Canna Lillies and Day Lillies Early June Texas

June Pocket Perennial Garden: Knockout Roses, Cana Lilies, Day Lilies, Dusty Miller, Rose Rosette Disease can be seen in the rose on the left of the image with the “Witches Broom” in ruby red colors. Miscanthus Maiden Grass in the background.