Weed control strategy important to lawns this time of year

     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.
     
      This time of year many of our plants are just now ready to come out of dormancy. They are just finishing their chilling requirement and are ready to start growing as soon as it warms up a bit.
      If the weather really gets warm too early, you will see many of the early bloomers and early growers get tricked into starting too soon. This can lead to early spring damage to plants.
      Weed control is very important this time of year. Crabgrass and spurge are just about ready to germinate if given the right conditions.
      This is why it can be so important to get that last application of turfgrass fertilizer on in late November. This last application improves the density of the grass stand and decreases lawn weed problems.
      I doubt if you can get any growth out of an application of a lawn fertilizer to a sparse lawn now to help prevent weed invasion.
      Mow it as high as you can to shade the ground as much as possible. Don't scalp dormant bermudagrass now; it's too early.
      Preemergent weed killers, if you use them, should be applied by mid February. A second application at half rate may be needed six to eight weeks later. Read the label.
      Also, don't forget to mulch. Two to 3 inches is enough. Applications of wood mulch need a nitrogen fertilizer applied on the soil surface before the mulch is applied.
      Soil applications of iron fertilizers should go on now to those plants that need it, particularly fruit trees.
      Roses should be pruned now or very soon.
      There are several classes in the community on pruning roses. Call our office at 257-5555 if you can't find one or if you want a fact sheet.
      Finish up your pruning now before new growth sets in on our woody plants. Cuts should be hidden from view as much as possible. Don't limb your cuts too high. Tender-barked trunks need shade from the canopy.
      Remember a good pruning job will look like no one has been there. The pruning is for the plant not the people.
      Applications of dormant oils and dormant sprays should be done soon. These applications are to help suppress mite, aphid and scale problems if you've had them in the past.
      Also, early spring vegetables can go in soon, such as radishes, spinach, lettuce, peas, broccoli and cauliflower transplants, and many others. Watch for cutworms to begin to become active in warmer weather.
      Fertilize those plants that will bloom early this spring such as iris, crape myrtle and lilac. Divide cannas if you haven't done it yet. Start looking for early bedding plants to go in soon.
      Prepare flower beds with organic matter and a starter fertilizer.
      If you need more advice, attend our next Home Horticulture workshop Feb. 2 at UNLV from 7 to 9 p.m.
      Question: I have blackberry plants and I never have berries. What can I do?
      Answer: Before jumping to any conclusions, make sure you're pruning properly. I would guess this is the problem more than fertilizing or anything else. If this doesn't work, call us back again and let's look into it further. Remember, the canes growing last year should produce this year.
      Canes growing in the year 2000 will produce in 2001.
      There are two types of blackberries; erect and trailing. The erect forms are just that: canes that are erect and are self-supporting. Trailing blackberries have canes that fall all over the ground and can grow rampant if left alone. These are commonly called dewberries and require some sort of trellising to support them while the erect forms do not.
      Examples of dewberries are loganberries, youngberries and boysenberries. Some erect types are varieties such as black satin, thornfree, chester's thornless and most of the so-called thornless types. I would highly recommend that you get a thornless type if you are chosing a blackberry.
      The easiest way to think of a blackberry is to remember that the root system is perennial and the canes are biennial. This means the roots live year after year and get larger in girth while the canes live for only two seasons.
      The canes arise from either buds located at the base of old canes (really the crown) or from roots. Canes arising from the roots are considered suckers and are usually removed.
      If you don't remove suckers and concentrate canes near the crown, a blackberry plant can overtake a garden in a very few years. Canes that grow the first season are called primocanes and usually don't produce fruit during the first year but just grow rapidly to support the fruit produced in the following year.
      There are some varieties, however, called everbearing types that will produce fruit at the tips of the canes in the fall of the first year and again lower on the cane in the following spring.
      The second year, the primocane is called the floricane since it will next bear flowers and fruit before it dies soon after the fruiting season. It is very important to remove dead canes in a timely fashion to prevent disease problems that might develop later.
      I am assuming you probably have a trailing type of blackberry since this is the most commonly purchased form. When dormant pruning in the dead of winter, select and keep six to eight of the strongest, most upright, 1-year old canes (floricanes) and remove the thin, weak and most horizontally growing ones (trailing canes).
      There should be 6 to 8 inches of space between canes. Remove any dead canes if you haven't already done so.
      You will now have to make a decision. Are you going to let the canes sprawl or are you going to trellis them?
      If you decide to trellis, the usual methods are to build a double wire trellis about 3 1/2 feet above ground running the whole length of the row or use a single 2-by-2-foot or 3-by-3-foot stake driven into the ground next to the plant.
      After winter pruning, about six floricanes are tied to the stake to force them upright for easier picking and handling.
      Next winter you do it all over again. Blackberry primocanes need to be tip pruned a few times during the summer months. Not all the canes grow at the same speed and time, so tip pruning will have to be done a few times during the summer months.
      Removing 2 to 3 inches of new growth from the growing tips will force the primocanes to create more lateral branches, thicken the canes and make the canes easier to work with.
      Q: Can I aerate and dethatch my lawn now?
      A: It would be all right to aerate now but I wouldn't dethatch it now. If you dethatch the lawn now you will open it up for weed invasion.
      I would wait until fall to do it unless you really need to do it now.
      If you do it now, be sure to follow the dethatching up with a high nitrogen fertilizer to get quick cover to suppress weed invasion.
     
     Bob Morris is a horticulture specialist with Nevada Cooperative Extension.