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April - 2009 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:
Is it possible to grow vegetables in a screened in porch. Our back yard doesn't get sun do to large pecan trees. Our front porch gets a lot of sun. But do you need insects for proper pollination?
Answer:
Many vegetables do not need to be pollinated by insects. For example: tomatoes, peppers, cole crops (broccoli, cabbage, kale & etc), leaf crops (lettuce, spinach, collards & etc), root crops such as onions & radishes, all do not need insect pollination. Tomatoes & peppers will probably benefit from a vigorous shaking every day while in bloom. However, it will probably be the lack of sunshine that will affect production. You will not know that unless you try.

Question:
We have lived in Hawaii twice and loved the Plumeria flowers. Any tips on growing a container plant here in San Antonio?
Answer:
If you grew the Plumeria in Hawaii as a container plant, it will be the same here in San Antonio except that it should be protected in the winter. Any time that the temperature is predicted to go to 45° F or below they will need to be brought into a protected location. This can be into your home, a greenhouse, or into an unheated garage. The plant will go dormant and drop all of its leaves if taken into a dark area and will only need a little bit of water (maybe a cup or two a month) during the winter. You would move it back outside when the temperature will be consistently above 45°.

Question:
Last year, you answered a question I had about picking off the "used" flowers of my crape myrtle in order to get another round of blooms. My question here is - Does this apply the same in picking off the spent flowerets from the Mountain Laurel?
Answer:
No, that will not work with Mountain Laurels. They only set bloom stems (buds) in the late fall, early winter. If you watch them late this year you will see the rat tail like grey growths that appear. These are the bloom buds.

Question:
Are bluebonnets dangerous in a horse pasture?
Answer:
Bluebonnets are somewhat toxic, but very distasteful to animals. Horses, cows and bluebonnets have co-existed for as long as they have all been around.

Question:
When is the correct time to plant caladium bulbs? Is it too soon to do it now?
Answer:
I recommend that you wait until about the 15th of April. That way the ground will be sufficiently warm for them.

Question:
I recently was given some seeds from a Mt. Laurel, I want to plant them but I'm not quite sure what to do. Please help. I really love the tree & would be so proud to have one that I grew on my own.
Answer:
Mt. Laurel seeds are difficult to germinate because of the very hard seed coat. There seeds are similar to bluebonnets in that it may take them 5 years or more to germinate naturally. You can help this along by scarifying the seed coat with a file or sand paper enough to barely break through it so that moisture can get into the seed and cause it to germinate.

Question:
I planted two wisteria plants 5 or 6 years ago and neither has ever bloomed. As I drive around town, I see neighbor's wisteria in full bloom while mine is just pushing out a few leaves. I've tried to be patient figuring it would take a few years, but I'm beginning to think I got a "dud". Any suggestions?
Answer:
There are several reasons for a wisteria not to bloom; it hasn't reached blooming maturity yet; it is getting too much shade; it has been pruned improperly (if pruned in winter - early spring, the bloom buds will be cut off; too much high nitrogen fertilizer causing vegetative growth at expense of blossoms. I don't know if any of these apply to your plant.

Question:
Can I use the leaves of the Mexican Bush Sage as a spice?
Answer:
I find nothing to indicate that the Mexican Bush Sage (Salvia leucantha) has any culinary uses. However, neither do I find anything to indicate that it is toxic. So I guess the choice is yours. As for me, I wouldn't use it, but try garden sage.

Question:
When is the best time of the year to prune Texas Mountain Laurel trees?
Answer:
Texas Mountain Laurel (Sophora secundiflora) requires little, if any, pruning. However, if you do need to prune it, you should do it immediately following its bloom. If it has not bloomed, you should wait until about mid April to prune.

Question:
A friend of mine offered me some live oak leaves she had raked from her yard. I plan to use them under a loquat tree and in a Xeriscape area consisting of a desert willow, salvia greggii, lantana and cedar. Another teacher said that the oak leaves are too acidic to be effective mulch. He said they may kill the plants. What do you think?
Answer:
Live oak leaves make good mulch for all plants. I use them extensively. They should be spread 3 to 4 inches deep under and around the plants. Any acidity that they might impart to the soil would only enhance it. I prefer to have them chopped up by a shredder or lawn mower but that is not necessary.

Question:
Please tell me the names of the best shade-tolerant, hardy, flowering annuals/perennials, which are really pretty and showy for a San Antonio flower bed.
Answer:
For show you cannot beat annuals such as wax-leaf begonia, impatiens and cyclamen. Perennials you can use include Mexican petunias (Ruellia spp.), Shrimp Plant, Four O'clock, Turk's Cap, and Autumn Sage (Salvia greggii).

Question:
Can Dahlia's be grown successfully in our area? I have seen numerous varieties in plant catalogs that say they are suitable in zones 5 to 9. Any suggestions?
Answer:
Dahlias are not suited for this area because of our heat. The smaller flowered, shorter bedding plant types might survive but the large ones will not. Those zone numbers refer to the minimum cold temperatures and not to the heat. USDA Cold Hardiness Zone 8 (which includes all of our area) can expect cold temperatures not to go below 10° F on the average.

Question:
What type of tree or shrub could I use to create a natural wall? I have an unsightly neighbor and would like to grow something tall and thick along the adjoining fence. It is a full sun location with lots of rock, little water and probably poor soil. Can you make any suggestions?
Answer:
What ever you plant is going to need water to get it established. Some that you might consider are Primrose Jasmine (Jasminum mesnyi), Elaeagnus (Elaeagnus pungens), Firethorn (Pyracantha coccinea, or Japanese Ligustrum (Ligustrum japonicum).

Question:
I recently planted some lovely red-tipped photinia. Now the deer are eating the red tips! Will the plants recover---what can I do to help and what can I do to prevent the deer from eating more?
Answer:
The only real solution is to prevent the deer from being able to get to them. However, this isn't easy short of a tall fence. I have had success with a product sold in many nurseries called Liquid Fence. It is a concentrate that you mix and spray on the foliage. It has to be reapplied regularly until the deer decide it isn't worth their time anymore. If you can keep the deer from eating them the plants will recover just fine.

Question:
How do I start an avocado plant from a seed? Water rooting has not been successful.
Answer:
Put the avocado seed in a container of potting mix with the pointed end up and the top of the seed barely above the soil. Moisten the soil and place it in a shady location. Keep the soil moist but not saturated until the seed germinates. After it has true leaves, gradually move it out into full sun - shade to part shade to sun.

Question:
How should one wash clothes worn while applying pesticide?
Answer:
Wear rubber gloves when handling pesticide contaminated clothing. Clothing that has had a highly toxic pesticide spilled on it should be discarded. For clothing that was worn while handling, mixing, or applying pesticides, first hang the garments outdoors to air. This will allow some of the pesticide to volatilize and will reduce the amount brought into the house. Pre-rinse the garment by hosing it off outdoors, rinsing it in a separate tub or bucket, or using a pre-rinse cycle in an automatic washer. Use a heavy-duty liquid detergent to pre-treat heavily contaminated spots or garments, and then wash the garments in an automatic washer, separately from any other clothing. Do not overload the washer - the fewer the garments, the better they will be cleaned. Use hot water, heavy-duty detergent in the amount recommended on the package for heavy soiling or hard water, and select the longest wash cycle offered by the washer. If the chemical used was highly toxic, run the clothes through the wash cycle twice. Rinse the clothes with two full warm water rinses. Line dry the garments so that any pesticide residue cannot possibly contaminate the dryer, and clean the washer of any residues by running it through a complete cycle, with detergent and hot water, while empty.

Question:
Are the mountain laurel berries poisonous to pets?
Answer:
The seed of the Texas Mountain Laurel (Sophora secundiflora) are toxic. However, the good news is that the seed coat of the bright red seed is extremely hard and will normally pass through the digestive system of the animal intact.

Question:
My two bougainvilleas were kept inside the cold months but now that I have put them back outside in the sun, and gave them some fertilizer they aren't blooming anymore. I didn't cut them back since they were blooming earlier, should I do that now and if so how much?
Answer:
Bougainvilleas bloom on new growth. Yes you should cut them back. Since I don't know how long the branches are, I would say that you should cut them back by half.

Question:
I don't know the botanical name for this plant, but it's called a "closet plant". My question is,
what is the reason for the tips of the leaves turning brown? I keep getting new growth, but the outline of the leaves turn brown.
Answer:
The plant is Spathiphyllum and is also known as Peace Lily. The most common reason for marginal desiccation is salt burn caused by a build up of salts in the soil from fertilization. This plant should be fertilized only when it is actively growing or flowering. Use one of the water soluble fertilizers such as Peters, Miracle-Gro, Rapid Grow or other such. When you water the plant you should do so until water drains from the bottom. This will flush out the salt build up. Discard the drainage water as the plant does not like to sit in water.

Question:
I live in San Antonio and have just purchased a Japanese Red Maple. Do I need to prepare the soil in anyway? Are these very adaptable to this area?
Answer:
The kindest advice that I can give you is to return the Japanese Red Maple to the seller. It is not at all adapted to your area, disliking the dry heat and the highly alkaline soil. It will not do well no matter how you prepare your soil. If you still insist in growing it, try a large container and shade it past 2:00 p.m. in the summer time.

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