QUESTION: One of my rose bushes has developed yellow leaves with black spots on them. What can I do?ANSWER: Since your rose bush has developed a disease called black spot, it means you are late in spraying the plant to prevent development of this fungus.This is a pervasive problem that is especially hard on hybrid tea roses.Take off all the leaves that are affected, and start spraying with a product that states on the label it works against black spot on roses (and other rose diseases as well).The label will recommend the timing. It is possible that more leaves will become affected before you get the problem under control.When you remove the diseased leaves, don't just drop them on the ground under the rose bush, because they hold the disease spores that will splash onto the rose bush again. Put them in the trash instead.And when you water those plants, try to keep from wetting the leaves. Direct the hose onto the root zone.

QUESTION: I have two rhododendrons; both are beautiful and healthy, but there are long extensions of branches with no growth, and then growth on the ends. I would like to trim these excess branches back for a more compact plant, but I'm fearful that the remaining old branches won't develop new growth. Do I trim just a few branches each season, or can I be aggressive and shape all at once?ANSWER: You can be aggressive with the goal of creating a plant with a more attractive shape. Those are mature, well-established plants that will see no harm from pruning and shaping as soon as the flowering season ends later this month.Cut back the long, gangly stems to the fullest part of the plant to create a well-shaped, oval or roundish plant.The rhododendron will look much better. Since those stems produce good blooms, they are healthy and should put out new growth.

QUESTION: We have an office fern. What's the best way to care for it? Filtered light instead of direct sunlight? What about watering?ANSWER: I'm glad to hear you have at least filtered light. So many offices today are like dungeons, with very little natural light. Ferns sold as houseplants will benefit from filtered light and should prosper in it. It is essential that you keep the plant watered and not let it dry out. Check the top of the soil every couple of days to make sure it's damp.Since your office is likely to have dry air, misting the plant every few days with water will help. Even with good care, you may occasionally see a browning frond. Just snip it off as close to the base of the plant as possible. The plant will eventually, in perhaps a year or so, outgrow the pot. Just replant in a pot about 2 inches bigger in diameter, using fresh potting soil.