Gardens preparing for spring

     By Bob Morris
     View columnist
      The following are issues our Master Gardeners deal with 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.
     
      What's happening in the yard and garden this time of year? Most plants by now have satisfied their chilling requirements for spring growth and are just waiting for warm weather.
      You should be seeing some new growth on roses in warm locations and this means aphids will be out. Prune roses as buds begin to swell and apply dormant sprays such as oils for aphid control. Your roses should be fertilized with your favorite fertilizer plus iron.
      I have seen some bud swelling on some plants already. We are in real danger of having some plant damage done to tender plants if temperatures get cold suddenly and drop to the teens or near teens.
      Get that application of nitrogen on tall fescue now if it needs it. Use nitrogen fertilizers containing nitrogen in the nitrate form or spray it on. This will give you a much quicker response in case it gets cold again quickly.
      Pruning of fruit trees and landscape plants should be about finished by now. Any removal of large limbs, such as those needing a saw or loppers, should be finished up by now if possible. Pruning with hand shears can be done anytime.
      Prune flowering shrubs after they finish blooming. Applications of iron to the soil for trees and shrubs should be done by now or at least before new growth. Soil applications of iron to woody plants are usually most effective with iron chelates containing EDDHA.
      Other products may or may not work depending on the soil chemistry. Follow label directions.
      Get any bare root plants purchased and in the ground as soon as possible. They should be in before you see new growth on the plant.
      Don't forget to mulch your plants. Fruit trees, shrubs, landscape trees all will benefit from a mulch. If the mulch is a coarse wood mulch then be sure to add nitrogen to the mulched area so you don't end up with a nitrogen deficiency due to the decomposing woody fibers in the mulch.
      Question: What should I be spraying on my fruit trees now for insects and diseases?
      Answer: Whenever possible try not to spray your fruit trees unless it's necessary. The main insect problem to look for is aphids on the new buds about to break.
      Their damage can be recognized by the cupping leaves that they create when feeding on soft, new growth. They also leave behind a sticky sap-like deposit below where they are feeding. They cluster around buds waiting for the warm weather and succulent spring tissue.
      Try either a spray oil or an insecticidal soap. These sprays are much more friendly with the environment than traditional pesticides. The primary disease that worries me the most during the spring months is fire blight because it can be so devastating.
      This is a bacterial disease that can be spread from flower to flower by insects or windy, wet weather or on the blades of infected pruning shears. Look for it primarily on apple and pear. Windy, wet weather when your blossoms are in full bloom is a dead giveaway that the conditions are prime for its spread.
      Watch for the hooking and jet-black discoloration of the of new spring growth. Prune out infected branches and disinfect the pruning shears after each cut.
      Q: How often should I be watering my fruit trees?
      A: If you are watering your fruit trees more than once per week, you are watering them too much. On extremely sandy soils, watering once per week is about right.
      The water should be applied evenly covering the area directly under the tree's canopy. On sandy soils, drip emitters should be spaced about 12 inches apart.
      If using bubblers, the soil should be forming a basin around the trunk and it should extend to the drip line of the tree. On sandy soils, the basin should be level and high enough to contain three inches of water.
      If the soils contain more clay, the basin has to be deeper (four or five inches) and the irrigations should be less often -- every two to three weeks. In all cases, the water should not collect around the tree's trunk or it will rot.
      Q: Is it too late to prune trees?
      A: No, but do it soon. As soon as new growth occurs this spring you are better off waiting until the majority of new growth slows before pruning more.
      Spring growth requires a lot of stored energy from the plant. The tree has been signaled by the environment that spring has arrived and it's time for leaves, stems and branches to grow.
      If you are going to prune now it would be best to remove entire branches to a "crotch" than "heading back" lots of individual branches.
      Once spring growth has begun you want to let the ends of branches continue to grow without interruption. These are sending signals back to the roots and coordinating root and shoot growth. However, light pruning can occur at any time.
      Once new growth begins to slow, root growth will pick up speed. A plant has a limited amount of energy and it must split up its sources of energy into whatever is growing: shoots, roots, leaves, fruit or seed.
      Q: What should I be doing to my lawn this time of year?
      A: Nothing if it's a Bermuda lawn except watering about once every two to three weeks so that the soil doesn't dry out. If it's a tall fescue lawn, now is a good time to fertilize with a complete and balanced fertilizer such as a 21-7-14 with iron. Half of the nitrogen should be slow release nitrogen.
      Check the label to see. If the lawn has been thin, power rake or dethatch and overseed the lawn with an improved turf-type tall fescue. There are so many new ones now its hard to recommend a favorite.
      Do not use K31 or Alta unless you had that grass to begin with.
      It is a wide-bladed grass that is more suitable for pastures. Top-dress the seeded areas with about a quarter inch of top-dressing. Your nursery will show you the right top-dressing to use. Use a roller to apply it.
      Don't overseed with tall fescue unless the night time temperatures have been above 45 degrees or it won't germinate.
      When it's cool like this, it may take up to two weeks for the grass to come up.
      Q: We have been unusually warm this last winter. What will this do to my plants or garden?
      A: Expect more insect problems than you have had in the past springs. The cold winters have a way of thinning out some of the insects that might be around the yard, both good guys and bad guys. This didn't happen last winter.
     n WORKSHOP -- Don't forget our Home Horticulture workshop at UNLV on today from 7 to 9 p.m. in White Auditorium. The topics in February will cover spring lawn care and how to grow juicy, tasty tomatoes at home. I will also finish soil preparation for vegetable gardens since we ran out of time in January.
      Call 257-5555 for more information and a map where it's located.
     
     Bob Morris is a horticulture specialist with Nevada Cooperative Extension.