Those red stems on a rose bush indicate a plant sickened by rose rosette virus

For The Baltimore Sun

My rose has some reddened stems, at the same time other stems are green. Is this just new growth? It looks weird.

Rose rosette virus has infected your rose. Besides reddened leaves and stems, disease symptoms include skinny (strapped) leaves, shoots crammed closely together (known as witch’s broom or rosette), super thorniness, distorted buds and flowers, and dead canes. Plant death is inevitable in 3-5 years. This virus is spread by mites the size of dust particles, carried on the breeze. An infected plant can host 40 times the normal population of these mites.

Remove the plant quickly. Bag the upper plant to keep mites from falling off, and cut it off at ground level. Mites do not live in the soil. You can dig up the rose’s roots later — no bagging required — and replant. All roses are susceptible to rose rosette disease, but it is manageable if infected plants are speedily dispatched. Invasive non-native multiflora rose can be a hotbed of infected mites, so remove any of those in the area, too, as a preventive measure. When an infected rose cannot be quickly removed, prune off symptomatic parts and bag those to reduce infected mite levels.

Many of my tomato seedlings ended up with nice full “head”, but sparse leaves along the stem. When a plant has a couple of leaves close to the soil, and others quite a bit farther up, should I follow the usual advice and plant the tomato only up to the lowest set of leaves? It seems this would waste a lot of stem that would not grow fruit.

Remove the lower leaves and cover most of the stem with soil. The buried stem will grow roots, and you’ll have a sturdier plant. For convenience, you can lay the plant sideways when you plant, so that you don’t have to dig a very deep hole. Caution: This is the opposite of the standard advice for trees, shrubs and most herbaceous plants, which should never be planted deeper than they grow in their containers or they will slowly die.

University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at Click “Ask Maryland’s Gardening Experts” to send questions and photos.

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