Rose rosette is spread by mites, not pollen

Rose rosette causes complete devastation to a rose. It is spread by mites. They cannot be killed and the disease cannot be controlled. Be on the lookout on your own roses. (Walter Reeves for The Atlanta Journal-Constitution)

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Rose rosette causes complete devastation to a rose. It is spread by mites. They cannot be killed and the disease cannot be controlled. Be on the lookout on your own roses. (Walter Reeves for The Atlanta Journal-Constitution)

Q: I’ve enjoyed my beautiful heirloom climbing roses for years. My neighbors planted red Knockout roses adjacent three years ago. Now my roses have begun to morph into something ugly. The bush is being taken over by gnarly, thick, red-tinted stems with thistle-like leaves that produce deformed blotchy pink blooms. I’m thinking cross-pollination with the Knockouts caused it. Tom Knechtel, Decatur

A: The ugliness might have come from your neighbor’s Knockouts, but it would not be transmitted by pollen. I think your rose has rose rosette disease, which is a virus. It’s spread from plant to plant by tiny mites. Unfortunately, it is incurable. I have plenty of details about the disease and lots of pictures at bit.ly/GArosette1.

Q: My friend’s irises have lots of little gray bugs on the leaves. What could they be? Mav Crocker, Senoia

A: I have no doubt that your friend’s irises are afflicted with aphids. These sap-sucking insects are common on iris and other plants. The usual initial control is a strong blast of water from your garden hose. Examine the leaves closely and you may see lots of tan “sesame seeds.” These are the skins of aphids that have been attacked by parasitic wasps. That’s why I don’t recommend insecticides in most cases. More details at bit.ly/GAirisa.

Q: We recently moved into a house that backs up to a creek. It rarely floods but stays boggy in the area that I’m hoping to beautify. I’d like to use some type of grass; would buffalo grass work? Matt Vestal, email

A: In a boggy area such as the one you describe, basket grass is what you might first see and then worry about. It is terribly invasive and quickly spreads by seed. It’s moderately attractive when mowed in the summertime, but it turns brown in winter. Buffalo grass is a native grass, but it rarely succeeds in Georgia. If you insist on grass, it might be best to resign yourself to a yearly (or more often) over-seeding using 8 pounds of fescue seed per 1,000 square feet.

Q: My African violets are growing on a long stem. How tall will they get? Veronica Perry, email

A: It’s common for the lower leaves on an African violet to shrivel and drop off. The lower main stem of the plant becomes bare and hard. You can shorten it by removing a half-inch of soil from the bottom of the root ball. Put the root ball back in the pot and add soil around the stem. This covers the exposed trunk, which will send roots into the new soil.

Email Walter at georgiagardener@yahoo.com. Listen to his occasional garden comments on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website, www.walterreeves.com, or join his Facebook Page at bit.ly/georgiagardener for his latest tips.