Back

April - 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:
Mr. Rodriguez, should I trim back the leaves of my sago palm that have turned brown from freeze burn? The stem itself is still green. The leaves however are brown.
Answer:
Those fronds will never be green again. So unless you want to look at brown fronds, remove them from the bottom of the trunk.

Question:
David, we have chickens in the neighborhood that roam around and love our front plant beds which are moist and have nice, loose dirt to dig around in. I tried putting hot pepper flakes in the bed, but they still come and dig and throw the dirt everywhere - I am tired of sweeping!! Anything you can recommend?
Answer:
Perhaps chicken & dumplings, fried chicken, or maybe roast chicken! You could put mulch in the beds that would prevent their scratching. I know of nothing else other than fencing them in or out. I doubt that the hot pepper is even felt by them. Sorry!

Question:
Can Freesia be grown successfully in our area? I received a small white freesia last spring and after the leaves died I planted it outside. I was surprised when in January it started growing. I now have a very beautiful plant with lots of blooms. The only thing I did was water it and use my house plant food on it. I would love to plant more.
Answer:
Freesia is not reliable in this area but I never tell someone that they cannot successfully grow anything as you have proven with your (I assume) florist plant. Freesia is not commonly sold in our local nurseries/garden centers so I cannot tell you where you might find them locally.

Question:
Mr. Rodriguez, I feel I may be a little behind the curve ball for this year, but I'm getting ready to install several raised-bed gardens and I'm having trouble finding some information. The garden will be situated on top of a very rocky hill, with the soil (what there is) being mostly a heavy clay. Do I need to add some type of drainage to the bottom of the bed? Also, since I will not be able to cultivate much of the existing area, how deep should I make the bed?
Answer:
There is no need for anything in the bottom of your bed other than the soil that you fill it with. I recommend that you have a depth of 8 to 12 inches of soil in your beds. Most purveyors of soils sell a mix of soil, sand, and compost that they call something like "three-way garden mix." This is what I recommend that you use.

Question:
Mr. Rodriguez, do San Juan climbing roses bloom the first year?
Answer:
Greg, it will depend on how much it was pruned before purchased. If pruned back hard, it probably will not bloom until the second year. Climbing roses should be left unpruned for the first two to three years.

Question:
David, can I plant a Norfolk Island pine outside? It's about four to five foot tall.
Answer:
Bill, you could but the odds of its survival are risky. The Norfolk Island pine (Araucaria heterophylla) is not recommended for planting in areas north of USDA Cold Hardiness Zone 9 and we are in Zone 8.

Question:
Mr. Rodriguez, what causes the leaves on my Lucky Bamboo plant to turn yellow?
Answer:
Steve, the most common reason is the fluoride in the tap water.

Question:
Dave, as part of the landscape package two oak trees were planted in my front yard in Dec. 2006. When can I remove the stakes and wire support from the trees?
Answer:
Helen, as a general rule supporting stakes and wires should be removed after no longer than one year. You should remove them now.

Question:
What causes the tips of a closet plant to turn brown? It appears I have a very healthy plant that blooms. However the very tips of most the leaves die.
Answer:
The most common reason for brown tips on the leaves of houseplants is the buildup of salts in the soil from the fertilizers used. To prevent this, the plant should be watered with enough water to cause it to flow out the bottom of the container each time you water. To flush out these salts that are now present, you should take it outside or place it in the bathtub and allow the water to run slowly through it for several minutes.

Question:
Mr. Rodriguez, I have a very large live oak in my front yard which for the past two years has had a fungus "fruit" growth at the base of the trunk, just above the ground. The bark around it has a whitish look to it. I have pried off the "fruit" twice now. Is there something I can or should apply to kill the fungus?
Answer:
I suspect that this fungus is Crown Gall. This is normally found at or near ground level but can be anywhere on the tree. It is usually not life threatening for the tree and I know of no way to kill it once in the tree. It is a bacteria called Agrobacterium tumefaciens which gets into the tree through a wound.

Question:
How long will a jalapeño plant continue to grow & produce? I have one that is nearing the one year mark and it is going full guns! It is potted on our deck. I have watered it correctly and brought it in when weather conditions were bad. It kind of hibernated during our mild winter and I was worried it would die. But a couple of weeks ago it bloomed leaves all over! And then it started growing at least 30 new buds! Is this normal?
Answer:
All of the cultivated peppers that we grow in our gardens (or containers) for eating or other culinary uses are part of the Capsicum annuum group. They are annuals or short lived perennials. Your jalapeño, if allowed to freeze would not survive. Since you have protected it, it will continue to live. I cannot tell you how long it will live. We normally advise people who have jalapeños plants survive in their garden to pull them up and start over with new transplants; as the chances are great the surviving plants will have insects or diseases or both, and may have been stunted, but not killed, by cold weather. If your plant continues to produce normal sized fruit, just continue giving it the necessary moisture, nutrients and light, and enjoy the fruits of your efforts.

Question:
David, I have several Indian hawthorns that are about 18 years old and have grown very "leggy" with sparse leaves. Can these be pruned back and if so, how far back?
Answer:
These plants should have been given minimal pruning over the years to stimulate new growth and keep them from getting leggy and woody. If you give them a severe pruning, the shock may kill them. If you want to enjoy these years' blossoms, I recommend that you wait until after its bloom period is finished and then selectively take long branches back to the next larger branch. However, you should not reduce the size by more than 1/3. You can repeat this next year. If you do not want to do this, my recommendation would be to replace them.

Question:
The bedding areas under and around my cedar elm trees get covered every year with cedar elm seedlings. What can I do to get rid of them? There are too many to pull.
Answer:
You should apply a broad leaf pre emergent herbicide to prevent new ones from coming up. You would do this about the time that they start dropping their seed. For those that have already come up, you can spray them with a glyphosate herbicide. You must be careful not to spray any other plants that you do not wish to kill. The glyphosate will not hurt the mother trees even if you get it on their bark. Just don't spray it on their leaves.

Question:
Mr. Rodriguez, I have sandy soil in my new lawn. I would like to plant bermudagrass seed this spring but have lots of sand burs and many weeds. Should I apply a pre-emergent to kill the sand burs? If so, how long must I wait before I can plant the bermudagrass seeds?
Answer:
If you use a pre-emergent herbicide for the grass area it will preclude planting the bermudagrass for about 6 months. Bermudagrass needs a very warm soil to germinate so I recommend that you do not sow the seed before the first of May. In the meantime kill all existing vegetation using one of the glyphosate herbicides. You can also drag an old carpet remnant over the area (pile side down). This will collect many of the seed. Then after your bermudagrass is up and well established, you can kill any sandbur plants that are growing with a post emergent herbicide called MSMA. This is manufactured by many and available at all nurseries/garden centers.

Question:
David, last year, I had an infestation on several of my crape myrtle plants in the front and back yards. I think it was the crape myrtle aphid - sticky, black, sooty surface of the leaves. I used nothing on the plants last year. No foliage is out yet but I expect these will return this year. Can I use an oil spray now to prevent aphids? Also, what is the best insecticide to use during the growing season and how often should it be applied? I was told oil to use Malathion or Neem.
Answer:
I do not know of a preventative spray for aphids. At the first indication of them, spray with any insecticide labeled for aphids. There are many - just ask your favorite nursery/garden center person. You should not have to spray any more frequently than weekly.

Question:
I planted the tomato varieties which you recommended and they are loaded with tomatoes. Now the leaves are beginning to turn yellow, then brown and die from the bottom of the plant. What should I do; will this kill my plants?
Answer:
You and everybody growing tomatoes are having the same problem. Tomato plants are developing brown spots on the lower foliage. This is the result of a fungus infecting the foliage causing a disease known as early blight. Early blight is an annual problem for most gardeners. It normally develops into a problem when plants have a heavy fruit set and the area has received rainfall. Spores from the fungus are spread to the lower foliage by wind, splashing rain, and poor irrigation practices. Leaves must be wet for infection to occur. At 50° F. the leaves must be wet for 12 hours for infection, but at temperatures above 59° F., the length of time for infection is only 3 hours. Leaf spot development is most severe during periods of cloudy days and high humidity. To control the fungus, foliage applications of a fungicide must be made every 7 days until moist conditions (dew included!) no longer exist. Applications should begin when the first fruit is slightly larger than a quarter. Chlorothalonil (Ortho Multipurpose Fungicide or Fertilome Broad Spectrum Fungicide) and Mancozeb hydroxide (Kocide 101) are fungicides used on tomatoes for early blight. The copper fungicides also are affective against the foliage and fruit-infecting bacterial pathogens. All listed fungicides can be mixed with insecticides or other fungicides except the copper-based materials (Kocide). The copper fungicides have a high pH which will reduce the life of many insecticides and some fungicides. Kocide is the only effective organic control for this pestilence.

Extension educational programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability, or national origin.