Problems with roses can come from numerous reasons

      The following are typical questions our Master Gardeners answer daily at the Nevada Cooperative Extension. If you have gardening questions, call the Master Gardeners' hot line at 257-5555 between 9 a.m. and 4 p.m. Monday through Friday. There is also a gardening Web site at http://www. intermind.net/mgarden/.
     
      Question: My roses have small leaves and they are brittle. The leaves are browning on the edges but the leaves are not dead. It is blooming but the plant looks overall just sick.
      Answer: Several things we have to keep in mind and we must ask some questions.
      The possible reasons might include the rose bush is planted in the wrong location, the rose bush was planted improperly such as too deep, the plant is being overwatered or underwatered, the soil doesn't drain properly, salts are building up in the soil due to some of the above reasons, an insect such as cane borer is infesting the plant, overfertilizing, a long, hot summer and a few other reasons as well.
      Let's walk through some of these.
      How long has the rose been in the ground in this location? If this is the first or second year for this plant then we can begin thinking the wrong
     selection, wrong location or improper planting.
      If the plant has been in the ground for several years and this is the first year it has looked bad then we might suspect insects, poor drainage or watering practices and fertilizing techniques.
      Roses are best with sunlight for most of the day but protected from late afternoon baking. They should be planted in the open and away from walls which reflect late afternoon sunshine.
      Is this variety suitable for Las Vegas? Do you know other people with this variety and have they had good luck with it? You might want to check with our Master Gardeners.
      Some of them are Rosarians and belong to local rose societies.
      If this is a new plant to your yard then you might investigate how it was planted. Planting too deep, combined with poor drainage and watering
     practices, can rot the stem and slowly choke the plant from its root system. Plant roses so the bud union is above ground. This can be seen as a swelling of the main stem located between the upper stems supporting the leaves and the root system.
      Roses should not be planted in rock mulch but rather in an organic mulch.
      They need a continual supply of organic material, rotting in the soil, to keep it healthy. This rotting organic matter helps keep minor mineral elements such as iron and manganese available to the plant and helps keep it green.
      Native desert soil should be amended with organic matter at the time of planting and the hole should drain easily when filled with water. Poor drainage will rot the roots and kill the plant.
      One of the early signs of a rotting root system is a plant with leaves that are scorched, covering the entire plant.
      Over-fertilizing plants will cause the leaves to scorch provided it doesn't kill the plant first. A quick way to kill plants is to throw a handful of fertilizer at the base of plants and then water it in. If that doesn't kill the plant, then it will certainly burn or scorch the leaves.
      Under- or over-watering may result in plants with identical symptoms. This means leaf scorch and poor growth. Overwatering, provided it is not terribly excessive, usually just makes plant growth rampant and luxurious. If that line is crossed between excessive and overly excessive, then the plant moves from a luxurious look to a sick look.
      Sick look means yellowing or scorched leaves, stem dieback and poor growth if not plant death.
      If an insect attacks the plant such as cane borer, then that part of the plant attacked will show the scorched leaves while the rest of the plant may appear healthy.
      Insect and diseases that attack a plant above ground and not in the main stem will cause the part of the plant attacked to show signs of the pest's presence while the rest of the plant appears unaffected.
      Q: My crape myrtle has no blooms and sparse foliage. What can I do?
      A: This sounds like some similar problems to the rose. But from past experience with crape myrtle my guess is this plant is not watered long enough during each irrigation. After a deep irrigation then the next watering should be held back until it is needed, possibly three days or more if established.
      If this plant is planted in a desert landscape surrounded by rock mulch, then it may be just too hot for it or not enough organic material used in the soil.
      These explanations may address the poor growth but not the lack of flowering. Crape myrtle sends out new growth in the spring. In the summer, flowers are formed on the spring growth.
      When the plant flowers, then side shoots supporting leaves sprout just below the flowers. After the flower is finished, the flower and the stem supporting it die.
      This results in little dead stems appearing all over the plant. This can look unsightly. The temptation is to trim all of these little dead flower stems off the plant to make it look better.
      This is fine to do if you do it in fall or early spring before new growth. If you wait to do it in the spring after new growth starts, then you run the risk of pruning off all of the flowers for the coming year.
      This is why we emphasize the basic rule of thumb in pruning flowering shrubs. The basic rule is to prune flowering shrubs directly after they bloom. Do not delay their pruning.
      Q: The top of my palm trees seem like they are "choked up" and the leaves can't get out of the top. My fan palm has browning leaves, they are curling and seem to be dying.
      A: Usually this is just a lack of deep watering. Palms are not true desert plants. Although they can be very tolerant of dry conditions, they require a great deal of water for their size. When palms don't get enough water they usually appear stunted with poor leaf development.
      When water is resupplied to stressed plants, they respond quickly with a vigorous flush of new growth provided it is during the summer.
      Another possibility might be poor plant nutrition particularly if the palms were planted directly into sterile sand placed in a planting hole. Look for fertilizers containing manganese and potassium to add to the planting hole.
      Q: My tomato fruit and plant had some sort of blight. Is the fruit safe to eat?
      A: Yes. Wash them thoroughly, remove affected parts of the fruit and they can be eaten.
      Q: I have weeds in my lawn. Can I spray for them now?
      A: It would be best to wait for cooler weather if you are trying to control perennial weeds such as dandelions, plaintain or chickweed. Annual weeds like spurge and crabgrass are best attacked with pre-emergents in the early spring.
     
     Bob Morris is a horticulture specialist with Nevada Cooperative Extension.