2012 June Q&As

Question:  We want to plant sunflowers (large head & seeds) at the hunting lease for the doves.  If we just plant the sunflower seeds that we buy to feed the birds, will they grow and will it produce the large heads with the same large seeds, or do we need to get another kind of seeds to plant?

Answer:  I recommend that you plant the common sunflowers or a mix of seeds especially for dove and quail.  Douglas King Grass Company (http://www.dkseeds.com/) here in San Antonio sells both.  The larger headed sunflowers need more care than the native sunflowers to be productive.

Question:  My one year old bougainvillea is planted on an arbor.  It doesn’t have any blooms on top or center.  Are bottom shoots supposed to be cut off?  We want it to cover the arbor.  Also, too many caterpillars are eating the leaves.

Answer:  Did the bougainvillea freeze last winter?  If so this may be the problem.  If you had any freezing weather or hard frosts, the vegetation would have been killed.  No, you do not have to cut the bottom shoots off.  Just train them up the trellis.  You should spray the bougainvillea with an insecticide labeled for caterpillars at the first sign of the leaves being eaten.  One containing Bacillus thuringiensis (Bt) is good and safe and affects caterpillars only.

Question:  We want to “set off” a shady bed at our church by planting some really red annuals in the center of a shady bed.  Besides Fire Spike can you suggest another?

Answer:  The annual red salvia should do quite well.  Most nurseries will have it available as Lady-in-Red or Red Hot Sally.  Also the Wax Leaf Begonia is available with red blossoms and either green or bronze leaves which is good in shade.

Question:  My Dwarf Owari Mandarin Orange tree is planted in the ground.  It puts on a lot of fruit, which get to the size of a pea and fall off.  Last year, one orange made it, this year they all turned yellow and fell off.  What would cause this?

Answer:  It may need more maturity to retain some of its fruit.  However, typical citrus trees go through three distinct periods of fruit drop and even mature ones will end up with far fewer fruit than blossoms.  I wouldn’t worry about it yet.

Question:  I have some gorgeous peaches for the second year in a row.  This year, I’m seeing some “rock salt” like clusters on my fruit.  I’ve been searching the internet but can’t find anything on this topic.  I suspect you’ll know what it is and whether it can be treated.

Answer:  More than likely this is the exudation produced by the fruit after it was fed by stink or leaf footed bugs.  Hopefully, it is just a few fruit that have this problem and you can remove them.  You may want to examine the tree for such insects and if present make an insecticide application, like Malathion.

Question:  What is the best time of year to prune shrimp plants?  Mine have had blooms since last October and still have blooms that are about 2 1/2 to 3 feet tall.

Answer:  I recommend that you wait until early next spring to cut them back.  These plants normally freeze to the ground each winter and come back from their roots.  Since yours did not freeze, they continue to grow and bloom.  If they do not freeze down this coming winter, cut them to the ground in late February or early March.

Question:  I need to know what kind of pear tree to buy to be able to grow and eat the fruit?  I am looking for a really good pear tree.  Also, how many trees do I need?  I was told I have to have more than one.

Answer:  Pears are cross pollinated, so plant a pollinizer variety at least 40′ from companion variety.  European Hybrids varieties include:  ‘Kieffer’, ‘Orient’,’ Moonglow’, ‘Magness’, and Asian Varieties- ‘Shinko’,and ‘Shin Li’.  The best varieties are probably the Orient and the Moonglow.  The Orient is a harder type cooking pear.

Question:  I am troubled by leaf miners.  I have searched the web and found some information about them, but have not found anything on getting rid of them on my plants, any suggestions?

Answer:  You do not say what plants the leaf miners are on, but they seldom do sufficient damage to warrant trying to control them.  Once the leaf miner larva is in the leaf between the top and bottom layers, there is little that you can do other than locating the insect (at the end of the trail) by squashing it or removing the leaf and disposing of it.

Question:  I have a Pride of Barbados plant that is losing leaves.  It was fine just five days ago.  I have been watering them two or three times a week.  Not sure what to do.

Answer:  It is normal for the Pride of Barbados (Caesalpinia pulcherrima) to lose some leaves.  If yours is losing a large amount of them it is probably associated with the excessive water.  They need to be in a soil that drains well.

Question:  I bought a Chinese hibiscus a couple of months ago.  I planted it in a container with Miracle Gro potting soil. It gets several hours of sun.  Initially, I used Miracle Gro liquid fertilizer, along with topical time-released fertilizer for flowers and veggies.  It gets a lot of buds, and then they drop off.  I don’t know what else to do and the plant itself appears to be very healthy.

Answer:  There are many reasons that hibiscus drop their unopened buds.  Primary reason among them is allowing them to get too dry, too much shade, or damage by very small insects called thrips.  You can tell if you have thrips by cutting one of the buds open and tapping it on a white paper.  If you see tiny, slender creatures crawling on the paper, they are thrips.  You can control them by spraying with a systemic insecticide containing Acephate.

Question:  I can’t find Mari-mums anywhere. Do you know where I can obtain some seed?

Answer:  Mari-mum is a catchy name given to large flowering African marigolds that bloom in the fall, similar to fall blooming chrysanthemums.  For years they were also sold as Discovery marigolds. This is what the Texas Superstar pamphlet has to say about them:  “There are several different varieties of African-type (large flowered) marigolds such as Antigua which can be used to produce the Mari-mum-effect.  The Mari-mum-type marigolds bloom two to three times longer than chrysanthemums and are very low maintenance.  ‘Tahitian’ is the newest selection available and does superb here.  It is recommended to purchase transplants that are not in full bloom, starting from August through mid-September.

Question:  Is it safe to transplant an established Pride of Barbados plant to another area of the yard during this heat wave?  If so, what is the best way to do it?

Answer:  This is not a good time of the year to try to transplant it.  A much better time would be after a freeze (or when the plant is dormant).  February is usually a good month.  Then the plant can reestablish its roots without having to worry about its foliage.  When you do move the plant, dig down and get a root ball as large as you can, at least 10 inches in diameter, and move it with the soil intact to a hole you have prepared in advance.  Backfill with the soil you removed from the hole.  Water it well and keep it barely moist until you see new growth.  You can then water and fertilize as you normally would.

Question:  I bought a morning glory vine a few months ago. The vine is flourishing, but it isn’t producing many blooms. It gets about three hours of afternoon intense sunlight. What do I need to do so that it will have blooms?

Answer:  It probably just needs more sunshine (6 hours plus) and less fertilization.

Question:  How do I care for my Texas Mountain Laurel?

Answer:  Texas Mountain Laurel (Sophora secundiflora) is native to limestone outcrops of Central and West Texas. It needs to be planted in a well-drained soil and may need to be raised up, as it cannot withstand constantly wet roots.  It should be watered at the base of the trunk about once a week until it can establish roots out into the surrounding area.  Once established it will need very little supplemental water as well as very little supplemental fertilizer.


David Rodriguez is the County Extension Agent-Horticulture for Texas AgriLife Extension Service in Bexar County.  To get questions like these answered, call the Bexar County Master Gardeners Hotline at (210) 467-6575, e-mail questions to info@bexarcountymastergardeners.org, or visit our County Extension website at:  http://bexar-tx.tamu.edu.



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