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Friday, February 10, 2012

February Todo List for the Orchard and Fruit Trees

·       Pruning should be mostly finished by February 1. You have a little bit more time for grapes, pomegranates and figs. I like to prune grapes as late in the season as possible to avoid any late freezing damage to the spurs.
Thrips damage to nectarines
·        Irrigations should begin weekly as soon as new growth appears. The number of minutes depends on the irrigation system and how many gallons per minute or gallons per hour the system delivers. Drip irrigation is in gallons per hour.

·        Begin spraying nectarines for damage to the fruit by western flower thrips. Damage is heavy scarring and droplets of sap coming from the fruit. Do not spray during bloom but immediately after the petals fall from the flowers. Use Spinosad in rotation with insecticidal soap and Neem.

·        Fertilize overwintering onions and garlic with high nitrogen once a month. Garlic and onions will resume growth with warm temperatures. Lightly fertilize garlic as it begins growing again. Onion transplants are normally planted around mid-March and should be fertilized with high phosphorus when transplanted and nitrogen a few weeks later.

·         Prepare smoking wood from prunings. The Orchard has smoking and grilling fruit would available at very reasonable prices. Wood includes peach, apple, pear, fig and others.

·         Fix rabbit holes in fences particularly asparagus. Birds will damage the leaves of broccoli and cauliflower but usually not the heads.

·         Lightly fertilize winter vegetables monthly with your favorite high nitrogen fertilizer.

·       Spray emerging and growing vegetables weekly with insecticidal soap. Make sure you spray on the undersides of the leaves.

·         When you put vegetable transplants in your garden make sure you apply Bt (Dipel or Thuricide) for cutworm control. Spray or dust the soil surface around transplants after planting. Repeat it according to the label until transplants gain some size.

·         Irrigate vegetables as needed. New transplants or emerging seed will need to be irrigated daily until you see strong growth. Established vegetables can be irrigated every two or three days.

·         Be sure to apply a surface mulch after planting vegetable seeds, particularly if they are small like radish, carrots and lettuce.

Persimmon response to compost applied to the soil
·         Check irrigation lines and vegetable plots for leakage. Tighten drip tape so there are no kinks in the drip tape.

·         Apply two, 5 gallon buckets of compost around the persimmons. They really liked compost.

·         Harvest asparagus about once or twice each week right now. As air temperature increases you will be cutting more often. When temperatures reach the high 80s or 90s, expect to cut daily. Cut off spears 1 inch below the soil surface.

·         Begin pruning grapes in February. Prune last year's growth back to 18 inches and finish pruning grapes to one or two buds at the end of February. Table grapes are slower to emerge and can be pruned later than wine grapes.
Grape cutting
·         Take grape cuttings to start new plants. Cuttings should include three buds and be the diameter of a good-sized pencil. When taking grape cuttings, make the bottom cut straight and the top cut angled so you know which end should be planted up. Be sure to label the cuttings.

·       Tighten grape trellis wires and refasten the cordons tightly to the cordon wire.

·       Write labels for vegetable seeds that were ordered.

·        Dig blackberries and plant them in 5 gallon containers with a bamboo stake to hold them erect.

·      Watch for tent caterpillar in apricots and plums. Apply Bt or Spinosad if you see them starting to form a nest.

·       Check irrigation bubblers for blockage.

·       Move straw bales to vegetable plots for mulching.

·         Monitor weather temperatures for freeze losses to fruit. If you see freezing temperatures, look in the Orchard to see which fruit trees have flowers which are open. These will be the most sensitive to freezes.

·         Begin weeding vegetable plots.

Monday, February 6, 2012

Work and Preemergent Herbicides for Rock Garden Weed Problem

Q. I have a rock garden that is ten years old.  We have fabric under the rocks to prevent weeds, but I seem to have more weeds each year.  Could you recommend any effective pre-emergent herbicides?

Weed seedlings
A. This will sometimes happen for a couple of reasons. These fabrics do degrade over time and some last longer than others. Those with a tighter mesh usually last longer than those with an open or woven mesh. Landscape fabrics should be overlapped so there are no gaps when it is installed. I am assuming you did all of that.

            There are some weeds they just don’t prevent such as Bermudagrass and nutsedges or nutgrass. The key to controlling these is to remove them as soon as you see them when they are young, and don't let them get older or they just get stronger and more difficult to control.
            Over time, dirt and dust accumulate in the rocks on top of the fabric and provide a place for weeds to grow. Some rock mulches, like decomposed granite or sandstone, degrade over time. Sandstone is the worst. As these break down and decompose they leave debris on top of the landscape fabric. This is a place where weed seeds can germinate.

            It is always best to get rid of these weeds as early as you can and don't let them get to the point where they flower and produce seeds. The seeds are spread all over the place. I always look at chemicals as a last resort. If you can spend a few minutes once a week just pulling weeds, 95% of the weeds that you see will pull easily. Pull them just after an irrigation and most will pull easily.

            In the same way, 95% of the weeds are most likely annuals. If you can kill the tops before they flower this will reduce the weed population tremendously. There are sprays that will “burn” the tops down and thus prevent flowering and consequently seeds.

            When we start talking about weed killers, we have to pair the weed killer with the weeds we want to kill. If we pair the wrong weed killer with a weed, it won't work and we blame the weed killer. So it is very important to know which weeds you are trying to fight.

Both contain Surflan but you would
not know it unless you read
the ingredients on Impede
            However, there are a few we killers that can kill a wide range of weeds, but again not all of them. Pre-emergent weed killers, aka pre-emergent herbicides, include a variety of products with many different marketing names. Some of the lesser known brands have the same ingredients as more expensive products but are not marketed as well.
            The pre-emergent products that you can get from your local nursery or supplier are going to be general, all-purpose pre-emergent herbicides. For instance one product by Monterey is called Impede. It contains Surflan which is a very good pre-emergent herbicide.
            I don't know it by its trade name, Impede, but I do know its active ingredient which is Surflan and that is a very good broad spectrum product. Other ingredients you can look for in the labeling that control a wide range of weeds are Dacthal, Ronstar, Goal and Treflan.
            Be sure to read the directions and follow them precisely.

Almost All Plants Like Wood Mulch - Even Desert Plants

Roses don't like rock mulch
Q. I heard it is best to move rock away from my shrubs and replace it with mulch.  What is your recommendation?

A. Rock can also be a “mulch” and we call it that in our desert landscapes; rock mulch. We have three categories of mulches; organic, inorganic and living. In the organic category are wood mulches. In the inorganic category we have rock mulches. All mulches are important but organic mulches, like wood mulch, give extra benefits to plants that rock mulches cannot.

            Our desert creates its own rock mulch and that’s why plants that originate from desert environments can “tolerate” rock mulches. It is not that they grow better in rock mulch but rather that they survive better in it.

            Nearly all plants grow better with organic mulch rather than rock mulch when grown in our desert soils. Plants like most of our fruit trees, roses, iris, lilies and those which are not true desert plants, perform better with wood mulch.

Mockorange yellowing in rock mulch
            Those that come from desert climates like mesquites, acacias, desert bird of paradise, agaves, cacti, etc. will tolerate rock mulch better than nondesert plants. But in most cases they still perform better surrounded by wood mulch.

            Newly planted trees and shrubs should have wood mulch kept away from them a distance of about one foot the first few years of their life. After that they usually tolerate wood mulch in contact with their trunk. This is because the wood mulch keeps the soil too moist and can cause the trunk to rot when they're young.

Controlling Growth of Shrubs More Than Water and Fertilizer

Q. You have always have stated to prune shrubs and trees when they are dormant, but it seems mine do not go dormant in the winter.  They continue to grow even though they get water only once a week.  I halved their fertilizer application but they continue to grow larger than I want them to. Why do they grow when they should be dormant and when should I prune them to slow their growth and spread?

A. Shrubs desire to reach their mature size. Keeping them smaller than this will require more maintenance than selecting one that is the size you need. Select shrubs by determining the size you need and finding one that fits that size at maturity.

            Dormancy here is not the same as dormancy in Minnesota. Dormancy here, in some cases for some plants, means that they may stop growing as much, not that they stop growing at all. Just depends on the plant and its location.

            Where the plant is located in the landscape also dictates its level of dormancy. Very warm microclimates in the yard may mean that some plants never totally shut down during the winter while in colder spots they do. Hot south and west facing walls with little winter wind are the warmest locations.

            Cutting back on water and fertilizer will help but they do not act like an “on and off switch” for plants. Think of fertilizer and water more like a “rheostat” where it can increase and decrease growth but not totally shut it down. At some point though, turning down the water and fertilizer will damage the plant. The real solution is to match plant mature size to the site.    

            Focus your pruning on older growth and remove it from deep inside the canopy leaving the younger growth still flourishing. Prune in the winter months. Avoid trimming on the edge of the canopy whenever you can. Hide your cuts if at all possible. They should not be obvious. This will help keep them smaller.

Winds Blew the Flowers Right Off My Peach Tree

Q. For the last two years in North Las Vegas heavy winds have come while my young peach tree was in bloom. Both years I wrapped it as best I could but the blooms were blown off the tree anyway. Do you have any good way to protect the tree during these windy times? You don't wrap your trees at the farm?

A. We don't wrap our trees and we are exposed to strong, cold winds from the northwest with recorded gusts of 70 mph. My guess is that the wind is channeling through that area which will increase its speed. I would suggest constructing a windbreak to protect that small area by diverting or slowing the wind. This can be made from fencing or evergreen plants.

            You do not need to stop the wind entirely but you can slow it down with a windbreak. Windbreaks should not be a 100% barrier to wind but allow about 20% of that wind to penetrate through it. Things like chain-link fences with PVC slats or woven materials placed along windward side of the fence will affect wind a distance of 5 to 8 times the height of the barrier.
            Wind will increase its speed if it goes from a large area through a small area such as between homes or into backyards. This can be a problem if this channeled wind enters small areas where fruit trees and vegetable gardens are located.

            Be creative. See if you can design a windbreak into your existing landscape that can help modify that part of your yard and make it more enjoyable.