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October - 2008 Questions &Answers Compiled by David Rodriguez County Extension Agent-Horticulture Bexar County

Special thanks to Forrest W. Appleton and volunteers of the "Master Gardener Hotline" in support of the weekly gardening questions and answers.

Question:
What is your opinion about using oak leaves as mulch? What kind of fertilizer would you recommend that we use if we plan to go organic.
Answer:
The oak leaves are the ideal mulch. They work better if they are run through a shredder/chipper or by using a lawn mower before use, but they will work without this. The benefit of shredding the leaves is that they decompose faster. Any fertilizer will do. Just remember that the organic fertilizers have less nitrogen content and you will need to increase the amount of fertilizer you use.

Question:
What is the hummingbird migration period? Though I have many hummingbird and butterfly attracting plants in my yard, I also augment with hummingbird feeders. Should I remove the hummingbird feeders during the migration period? If so, when should I remove the feeders and when can I put them back out?
Answer:
You can keep your feeders out year-round with no harmful effect. There are a few hummingbirds that over winter in this area and you might be lucky enough to have one or more.

Question:
What is the most effective and safest way to kill Bermuda grass in my beds? My flowerbed contains mostly xeriscape plants (mountain laurel, Russian sage, salvia, lantana, etc.)?
Answer:
You can use any of the "over the top" grass specific herbicides without harming your ornamentals. They are sold at all nurseries/garden centers under such names as Ornamec, Poast, Vantage, Grass-B-Gon, Fusilade II and many others.

Question:
In our backyard, we have a problem with large, nasty, brown colored mushrooms. They have begun to come up all over one part of our yard. We have to pull them up or they end up rotting and making a nasty mess if you step on them. Is there something I can spray or spread in the St Augustine grass to prevent them from growing?
Answer:
Those mushrooms are growing on some organic material in that area - dead tree roots; bark chip mulch that have become incorporated into the soil or something else. However, although obnoxious, they are harmless. You can rake them or pull them out, but I know of no way to prevent them until whatever they are growing on has been consumed.

Question:
I have a beautiful sweet basil plant that keeps going to seed. I take the flowers off and in a couple of weeks it starts again. Can I use the seeds for eating or drying?
Answer:
If you leave the blossoms on long enough for them to set and make seed the plant may decide that it has done what Mother Nature wanted it to do and quit growing. I recommend that you pinch the flower spikes off as soon as you see them. The more you prune your plant, the more it will grow.

Question:
We are starting to think about transferring plants to our greenhouse and have a question regarding our mandevilla plant. It is on a trellis and approximately 9 ft tall. Do we cut it back before we winter it indoors and if we do, do we severely cut it back or just lightly trim it?
Answer:
I would not prune it any more than is necessary to get it into the greenhouse. When you move it back out next spring, you can prune it as much as you wish.

Question:
What can we put on our blue plumbago plants to get them to bloom a deeper blue?
Answer:
The color of the blossoms on your plants will remain that color regardless of what you do. If you want a deeper blue, you will have to purchase plants with that blossom color. Until recently the sky blue and white were the only colors available. However, selections with the darker blue are now on the market such as imperial blue.

Question:
I have a very old oak tree that is about 40 to 50 inches in diameter and has a canopy about 50 to 60 feet wide. At some point in the distant past, a limb was either removed or rotted away. When we first moved here in 2001, a knot existed where the limb was removed. Subsequently, the knot (which is about 12 inches high and eight inches wide) has rotted away. That has left a hole in the tree which is holding water. The tree is otherwise healthy. How do I save this tree?
Answer:
Other than the fact that it provides a breeding place for mosquitoes it is causing no damage. It used to be thought that a hole should be drilled up into the cavity to drain the water but this was found to not only be ineffective, but, if this could actually allow diseases to enter the tree through the wound of the hole drilling. It was also common for the hole to be filled with concrete or another substance. This was found to cause more damage than good because the material in the hole expanded and shrank at a different rate than the wood and did not seal the hole. So the consensus is now to do nothing.

Question:
Can you tell me where to purchase onion bulbs for planting in our fall garden. We have looked and have not been able to locate any.
Answer:
Growing individual onion bulbs is not recommended in this part of the country. Those varieties are considered long day selections and do not grow well here. We can successfully grow short-day and intermediate selections. Onion transplants are normally available and planted from mid-November to January. However, you can start seeds to grow into transplants starting in mid-October through December. The Texas 1015Y onion derives its name from the fact that its seeds are planted around October 15 in the Rio Grande Valley and the bulb is yellow. For more information and recommended varieties for this part of the state, visit http://Dixondalefarms.com website. They are the primary supplier of onion transplants in Texas and in the nation.

Question:
Our fruitless Bradford pear tree is losing leaves already. There is an area at the top that appears to be dying. The tree is eight years old and we have not had any problems with it until now. Can you advise me what the problem may be?
Answer:
I suspect that the problem is directly associated with the extremely dry weather we had prior to July. The rains of July and August have kept most of it alive but the damage was already done. You will probably lose that area at the top. The only advice I can give you is to make sure that the tree isn't stressed for moisture again as it was during the previous eight months.

Question:
Mr. Rodriguez, I had my landscaper apply fertilizer to my St. Augustine lawn. Thereafter, we had a slight shower, so I didn't water the fertilizer in. The grass is now turning yellow and I have been watering it often. Am I applying too much water or did the landscaper use the wrong fertilizer? If it is the wrong fertilizer, can I reapply more fertilizer soon?
Answer:
If you look around at other St. Augustine lawns, you will see that yours is just one of many that are showing yellow at this time. It's just showing its displeasure with our soil and lack of consistent rainfall. It will grow out of it. Not to worry.

Question:
I am a student at the Health Science Center studying to be a physician assistant. As part of our education, we are planning on making a demonstration garden for the people of Laredo. I am trying to find out what plants would be best to grow in a container garden in Laredo. I tried finding the answer on the website, but was not able to. Could you please help and point me in the right direction?
Answer:
One of the most significant benefits of container gardening is that it can be done almost anywhere without regard to the soil and climatic conditions of the area. However, be sure to be mindful of the light moisture, and fertilizer requirements of the plants used. There is no list of container plants for Laredo but work with a certified nursery professional at a nursery close by to help with your selection of annual or perennial plants.

Question:
My mother has two mountain laurel trees that I would like to move and replant in another area. One is 30 years old with a 9" diameter and the other is 20 years old with a 6 1/2" diameter. These beautiful trees were grown from seed and they mean a great deal to her. I need to remove them from the construction area and would like to save them. How can I move them myself with the greatest chance of success?
Answer:
I hate to be blunt and disappoint you, but you cannot do it without killing them. The only way that it could be done with any chance of success is to have them transplanted by a professional with a "tree spade" (a piece of equipment that digs them and moves them with a large root ball intact). Even this would be no guarantee that they would live. Texas mountain laurels are among the hardest to transplant and the age of those just makes it more difficult.

Question:
Your internet information about plumbago says they should be pruned to the ground in the fall or winter. My question, as I have never pruned my plumbagos that severely in the past, do I risk killing them by cutting them to the ground? And, by 'cutting to the ground' does that mean leaving about 6" of plant stalk?
Answer:
Blue plumbago is one of those woody perennials that, if it doesn't freeze back to the ground and not pruned, tend to get woody and sparse. Therefore, I recommend that it be cut back to the ground (you can leave a little stubble just so you know it is there) early each spring prior to any new growth. It will quickly reestablish itself. Of course, if it freezes you can go ahead and cut out the dead material whenever you please.

Question:
This is the second year for our zoysia lawn and it never greened up well. I fertilized and water my lawn as I was instructed. What should I to improve my lawn next year?
Answer:
This has not been a good year for landscape plants, especially turfgrasses due to the lack of rainfall. I recommend that you continue to water the grass, one inch per week in the absence of rainfall, and fertilize with one of the 'winterizer' fertilizers between October 15 and the 31st. The one most commonly sold around San Antonio is 18-6-12 analysis. Ensure that the fertilizer is watered-in well. Without rainfall this winter, you should continue to water the grass at least once a month.

Question:
When is a good time to plant dwarf and regular crape myrtle trees?
Answer:
Fall is the optimum time to plant most trees and landscape shrubs. You probably will not be able to find crape myrtles that are blooming in the nurseries andgarden centers at this time. You will have to trust the tag information for its color and size. Crape myrtles have been known to frequently be mislabeled. For this reason, I recommend that they be purchased and planted when they are actively blooming.

Question:
I have many day lilies and they are beautiful. I planted them a few years back and don't know if there is anything else I should be doing with them. When the brown stalks appear, I pull them out but nothing more. Should I be "pruning" these since some of them get pretty tall? If so, when & how? Or should I just leave them be?
Answer:
You need do nothing to your day lilies unless they are so thick that it is affecting the blooming. If so, you should dig them up, separate (or cut clumps into smaller ones with a sharp knife) and replant them. This is usually done about every third year. You should fertilize them in the early spring with one of the lawn fertilizers such as a 19-5-9 analysis.

Question:
I have lost almost all of my live oaks trees to oak wilt, about twenty plus trees. Most were 20 to 40 plus years old. I will be "pulling" them up to prevent them from falling on my roof. What kind of tree can I replace them with and do I need to treat the ground they were in before I replant that area? I was thinking of crape myrtles, red bud, and/or ligustrum as they seem to grow kind of fast and would provide shade, beauty, and privacy.
Answer:
There is nothing that needs to be done to the soil. You can use any of the trees you mention as well as many of those listed in the recommended list of landscape plants at http://aggie-horticulture.tamu.edu/plantanswers/publications/southcnt.html. You can plant oaks but I would recommend that you use a mixture of trees so that you will never be faced with losing all of them as you have. Some of the oaks that are resistant to oak wilt are Mexican White oak and Chinkapin oak. Both of these trees are fast growing and well adapted in the landscape.

Question:
We have several giant liriope plants that were planted more than 10 years ago and they are currently very crowded together. We have created an area that we would like to transplant them to. When would be the best time of year to do this? We are also concerned about how to prevent the most damage to their root system, and how to prepare the area we are moving them to.
Answer:
You can go ahead and prepare the area you are going to transplant into by tilling in about four inches of good enriched compost. Then the area will be ready for you to transplant the new plants. I recommend that you do this in the early spring before any new growth occurs. At that time, cut off all of the foliage and with a good, sharpened spade; dig up the plants you want to move. Move them to the new area and water them in well. This will cause no damage to the root system.

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