Graham County Gardening Newsletter

Transcription

1 Graham County Gardening Newsletter August/September 2003 Why? Because We Are In A Drought! Over the past few years, calls into the extension office about unhealthy trees and plants have risen significantly. It is not uncommon to visit with a homeowner and hear the following conversation; I have lived in this valley for 20 years and this pine tree in my front yard has been healthy for all that time and just recently it is dropping more and more needles and has bare spots throughout the canopy. What is wrong with it? The problem that many plants and trees are facing in our community is the same problem that many of the forest trees and plants are dealing with and that is drought. Since the early 90s we have seen a steady decline in the amount of rainfall received in the valley as recorded by the National Weather Service. The long term mean annual precipitation ( ) for our valley is 9.07 inches. As shown in Figure 1, the decline in precipitation has been fairly consistent since I think that even though we are feverishly trying to irrigate our trees and plants, the lack of rainfall (pure water) has had a tremendous effect on our landscape in the valley. A couple of things to remember is that we tend to not irrigate our trees during the winter months, and that is usually not a problem because we receive sufficient winter rains Precipitation (inches) Mean Annual Precipitation Long Term Mean ( ) Year *Through July 31, 2003 Figure 1. Mean annual precipitation in the Safford Valley as recorded by the National Weather Service. Mean ( ) to take care of our plants. However, recently those winter rains have been fairly non existent. We also are irrigating with water that is typically high in soluble salts. Saline irrigation water added to our already saline soils makes conditions even more difficult for the already stressed trees and plants. Trees and plants are a lot like humans, when they become stressed they are much more susceptible to infection by insects and diseases. So what can you do? Try and keep the trees and plants as healthy as possible. If you know you re irrigating with high saline water you can help prevent the buildup of salts in the soil by adding a little bit more than what the plant requires thus helping to flush salts out of the root zone. This will help to maintain a more favorable soil environment for your plants and trees. Also, irrigate your plants and trees periodically during the winter months to help maintain their health and last of all, keep hoping and praying for rain. * For more detailed information on gardening call the Cooperative Extension Office at Randall Norton, Ph.D. Extension Agriculture Agent Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director, Cooperative Extension, College of Agriculture & Life Sciences, The University of Arizona. The University of Arizona College of Agriculture & Life Sciences is an Equal Opportunity employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to sex, religion, color, national origin, age, Vietnam Era Veteran s status, or disability

2 In the August Garden: Plant beets, broccoli, Brussel sprouts, cabbage (seed), carrot, chard, radishes and turnips all month. Plant beans and kohlrabi, through the 15th of the month. Plant kale, lettuce (head and leaf), green bunching onions, peas and spinach from August 15th on. Keep pepper, cucumber, squash and tomato plants evenly watered to prevent blossom end rot. Pollination often suffers when temperatures are high. Healthy growth and fruit production will resume when the temperatures drop. Fertilize lawns monthly through the summer with a high nitrogen fertilizer. Bermudagrass needs to be watered about every 3 days during the heat of the summer. If you notice sizable wilted patches of dull, bluegreen grass that does not spring back after being walked on, it is time to water. Give lawns special attention where tree roots compete for moisture. Sow seeds of pansies, snapdragons, stock, sweet alyssum and violas in pots or flats. Transplant them into a garden in a month or two, when weather has cooled. Shear tops off ragged looking petunias, feed a high nitrogen fertilizer and water; plants will bloom again within 4 weeks. Cut back chrysanthemums to about 8" high or pinch back smaller plants the first of August to encourage bushier plants and more flowers in the fall. Make sure drip irrigation tubes are not blocked. Continue to deep water trees and shrubs through the heat of the summer. Plant beets, broccoli (there is a chance of heads freezing when planting this late), brussel sprouts (see broccoli), cabbage (plants), carrots, cauliflower (see broccoli), chard, garlic, kale, leaf lettuce, leeks, mustard greens, parsley, onion seeds, green bunching onions, peas, radishes, and spinach all month. Plant head lettuce through the 15th of the month. Bermudagrass that is not to be overseeded with ryegrass should be given one last dose of fertilizer before cooler temperatures slow growth. Begin decreasing the amount of water by a little bit each week. If you are going to overseed your bermudagrass with ryegrass, prepare it now. Plant the seed between September 15 and October 15 for best results. Transplant pansies, snapdragons, stock, sweet alyssum and violas into the garden. Begin planting spring bulbs such as iris, tulips, daffodils, crocus, and hyacinth now through November. Dig and divide crowded iris rhizomes. Set out larkspur, lobelia, pansies, snapdragons, stock, and sweet alyssum. Direct seed African daisies, other daisies, alyssum, aster, calendula, carnation, columbine, hollyhock, lupine, phlox, poppies, petunias, pansies, statice, sweet peas, verbena, wildflowers, and other cool season flowers in the garden. Fertilize trees, shrubs, vines, roses, and flowers one last time to help them recover from the heat. Fall is the best time to plant perennials, trees, and shrubs. Cooler temperatures allow the roots to grow all winter without having to worry about supplying nutrients and water for top growth. When spring comes, the plants are ready to grow like crazy. In the September Garden:

3 Upcoming Events: October :00am to 5:00pm Daily Boyce Thompson Arboretum Fall Plant Sale Thousands of drought tolerant plants will be for sale, ranging from shrubs, vines, trees, cacti, and succulents. This sale provides visitors with the opportunity to see mature species of plants throughout the grounds. Horticulturists will be on hand to answer questions on weekend days. For more information go to October 4 5 Tucson Botanical Gardens Fall Plant Sale At this huge plant extravaganza, find a great diversity of drought tolerant plants, including many natives, available for Tucson's prime planting time. For more information go to: September 6 9:00am to 1:00pm Cochise County Master Gardeners Fall Xeriscape Tour. Tour low water use landscapes in the Sierra Vista area. Details will be available in August from the Cooperative Extension office in Sierra Vista. (520) ext Gardening and Landscaping The Fall Version Sign Up Now!!! The University of Arizona & Eastern Arizona College are offering GARDENING AND LANDSCAPING to be taught at Eastern Arizona College in the Fall 2003 Semester Register for this course at E.A.C. NOW Course # 1825 August through December Monday afternoons 1:00pm to 4:00pm First Class Session is 18 August 2003 Topics to be covered include pruning, diagnosing plant problems, fruit tree cultivation, vegetable gardening, lawn care, plant propagation, greenhouse production and design, and landscape design along with many other topics. The course will also include a private tour for the class members of the Eurofresh greenhouses in Bonita. Come and join us for a fun, interesting, and informative time in this years gardening and landscaping class. Course will be taught by: Randall Norton, Agriculture Agent The University of Arizona, Graham County Cooperative Extension. Guest speakers on specific topics will also be included. If you would like to enroll go to EAC and sign up for Gardening and Landscaping Course #1825 and we ll see you on the 18 of August. For more information on registration please call :00am to 5:00pm.

4 Organism of the Month: Texas Root Rot (Phymatotrichum omnivorum) Cotton (Texas) root rot is a problem that most valley residents have experienced if they have tried to grow trees and shrubs in this area. Texas root rot is caused by the fungus Phymatotrichum omnivorum and is fairly widespread in our desert soils. Even though this disease has been thoroughly studied since its discovery in 1888, there are few options for control due to its unique characteristics. Symptoms of infection are very similar to water stress. As roots become infected with this virus they no longer are able to transport water from the soil to the upper portions of the plant. Leaves will begin to yellow and within as little as two weeks the plant will be dead. Characteristic of death by root rot is the fact that the leaves will typically remain firmly attached to the plant. The fungus is most active during the summer months when temperatures both in the soil and air are high. A plant that has recently died may be extracted from the ground and inspection of the roots will determine whether the tree was infected by P. omnivorum. A good hand lens will reveal fungal strands that appear as threads on the surface of the infected roots. The only known remedy is to plant resistant or non host plants. These include plants that are monocotyledonous meaning grasses, palms, small grains, corn, etc. Most native desert plants such as mesquite are known to be tolerant of infection. If you suspect root rot has killed any of your plants call the extension office or bring root samples in and we will help verify the infection. Insect (is it really?) of the Month The Wolf Spider (Lycosa sp.) Spiders are not actually classified as insects. They actually are in the class arachnida. Spiders are different from insects in that they only have two body parts while insects have three. Spiders have eight legs and no antennae while insects have six legs and antennae. Wolf spiders are usually rather large (from a half inch to two inches) hairy spider that are not associated with webs. They look much more menacing than they actually are. Wolf spiders are so named because it was once thought that they hunted for prey in packs. Wolf spiders are excellent hunters and unlike other spiders do not use a web to catch their prey. Wolf spiders are usually active by night and may be found around doors, windowsills, houseplants, basements, and garages. They are really quite harmless. In fact, we have very few spiders that actually present a potential health threat in Arizona. These include the black widow and the Arizona brown spider. Spiders are usually considered to be beneficial because of their appetite for other insects. They will eat roaches, crickets, flies, and other household pests. So, next time you see a large wolf spider making its way across the living room floor, don t squash it! If you truly are arachnophobic, herd the little critter outdoors. A general chemical spray for spiders is not recommended unless an infestation is severe. Most spiders can be dealt with on a one on one basis.

5 Graham County Master Gardener Business and Executive Committee Meeting August 7, :00 pm Phelps Dodge Room of the Safford/Graham County Public Library Person with a disability may request accommodation, such as a sign language interpreter, by contacting UofA Graham County Cooperative Extension at Requests should be made as early as possible to allow time to arrange the accommodation. ARIZONA COOPERATIVE EXTENSION U.S. DEPARTMENT OF AGRICULTURE THE UNIVERSIT Y OF ARIZONA TUCSON, AZ OFFICIAL BUSINESS PENALTY FOR PRIVAT E USE $300 PRSRT STD POSTAGE & FEES PAID USDA PERMIT NO. G 268