Q/A column – for release October 22, 2008

Dan Culbert - Extension Horticulture Agent 

 How Does Your Garden Grow? 

Tangerine Dieback

I have an early-bearing tangerine hybrid about seven-years old. For the last two or three years whole branches have died back, with peeling bark and cankers. I’m afraid I am losing the tree. Is there anything I can do? - Alan -

Branch dieback on citrus trees is not uncommon when trees are stressed by cycles of strong winds, drought, and then flooding.  Excessive dieback can be an indication of root damage from stressful environments which often encourage insect or disease problems.  Peeling bark and cankers can be an indication of some citrus diseases.  The term canker means different things to different people – some “cankers” turn out to be harmless lichens that just grow on the bark of citrus trees.

I certainly hope it is not the dreaded citrus canker, which looks like raised brown spots surrounded by a yellow halo.  Because Citrus Canker is so easily transmitted, we do NOT want folks bringing in diseased citrus branches.  A better approach is to get us a clear picture showing us what you see is going on.  Or, come by our office to look at one of our University of Florida picture guides to citrus pests and problems.  Identification of symptoms is the first step in solving branch dieback.

Be sure you are providing adequate citrus special fertilizers to insure that a young tree is not stressed by nutritional deficiencies.  Watering in times of drought will also help dooryard citrus trees produce high quality fruit in the Florida Yard.   Dead branches can be pruned back into healthy green wood; otherwise, pruning of citrus trees is often not necessary.   

 

Fallen Fruit

How much water do zucchinis need? When is the best time to start planting zucchinis from seeds? My zucchini plants started out beautiful, the fruit started, then the leaves turned yellow and all my plants died. The fruit also turned yellow and never matured. What did I do wrong? - Denise -

 

Zucchini and most other vegetable plants only need ½ inch of water each week through most of our gardening season (i.e. “the winter”). With all of our recent rain, few gardens have needed supplemental watering.   Zucchini and other “summer” squash can be planted here from September through October or from January to March for a spring crop.

 It may be that your flowers were not pollinated because not enough bees were around or as you suspect, they may fall off it there was too much water.  Another possibility could be blossom end rot – a lack of soluble calcium. Unless there is proof of some specific disease, the use of a fungicide is not recommended.  Bring in a sample of your fallen fruit to help find out of any of these conditions exist.

 

Field grass in my lawn

This isn’t about a garden, but grass, how does one get rid of what I call field grass which I believe is a form of a weed, but also looks like a form of grass. How would you grow good grass, can you plant it in spots and it will spread? Is there a way without moving out all of what’s there and putting down all new sod? It’s impossible for me to do financially that way. I have 3 acres I want to get [the weeds] out and have new grass growing on. Help!   Miss K

The key to having a great looking lawn is to follow three basic rules for growing good grass:  Mow correctly (cut the lawn to a 4” tall height), fertilize correctly (use a no-phosphorus, slow release granular fertilizer applied at 1# N/1000 square feet 2x year), and water correctly (1/2 inch of water per application; don’t water again till the grass starts to wilt.  Following these three rules will prevent most weeds from getting into your lawn.   If your lawn isn’t healthy, make sure that the grass gets 6+ hours of sunlight, and be sure that your pH isn’t too high or low.  Violate thee rules and you get pests: insects, diseases and weeds are all pests. 

 When you are not healthy, take your medicine. When your lawn is not healthy, the medicines are called pesticides.  To “prescribe” the right kind of weed killer, I would need to know the kind of grass you are growing, (Bahiagrass and St. Augustinegrass are the best ones for our area) and the weed that is causing problems.  Bring a sample of the weed by our office or send us a clear picture so it can be properly identified.

If less than half of the plants in an area of your lawn are not the kind of grass you want, it makes sense to kill everything and start over.  The area you are renovating might be small or large, and can be done in stages from small bite sized chunks to entire landscapes, depending on how much money you have to spend and how quickly you want to see results.  Using a non-selective weed killer with glyphosate (e.g. Round-up) kills everything, waiting a few weeks, then replant by sodding, plugging, sprigging or seeding.  Some of this renovation could be done now if you want to use annual ryegrass for the winter, but permanent lawn replanting should wait until spring.  Call our visit our office for more details.