2012 April Q&As

Question: My backyard had quite a few weeds which had grown over since the winter.  I did bag the clippings, when I made the first mow of the season.  Can I mulch the clippings or will I just be spreading weeds when I use the mulch for planting beds and spread throughout my lawn.  Probably 90% of the clippings are rye grass and weeds since my St. Augustine was still quite low.

 Answer:  I would not use them as mulch without composting them thoroughly.  Many of those weeds had mature seed on them, which you do not want to spread to your planting beds or lawn.

 Question:  I have brown patch in my St. Augustine grass and need some HiYield fungicide 10% PCNB with terrachlor.  I believe fungicide will stop the problem, but I’m unable to locate the fungicide anywhere to buy.  The company that provided this fungicide went out of business.

Answer:  Evidently, the products containing pentachloronitrobenzene (PCNB) are no longer available.  There is a Fertilome product called F-Stop which contains a Dow Chemical product called Eagle® fungicide that has been effective in preventing and controlling brown patch.  It should be available where HiYield and Fertilome products are sold.

Question:  Is there anything we can add to the soil to encourage our Texas Mountain Laurel tree to bloom darker?  My neighbors have dark purple blooms and ours are mostly lavender.

 Answer:  The color of the flowers of individual Texas Mountain Laurel trees is determined by their genetic make-up and cannot be changed.

Question:  I’m growing field cactus for ornament use.  Is there a herbicide that will kill grass and weeds that are growing in and around the cactus without damaging the cactus?

 Answer:  If you are talking about prickly pear cactus, you can over spray them with a herbicide containing glyphosate.  You need to take care not to spray any other ornamentals that you do not want to kill.

 Question:  As our trees are maturing, our shade area is expanding as well.  My husband was told that Turf-falo was great for shady areas.  What are your thoughts?  

 Answer:  I have no experience with this product.  However, I have sincere doubts about it having shade tolerance.  My experience with buffalo grass as a turf grass has not been good.  It is a clump grass that does not get sufficiently thick to compete successfully with weeds and Bermuda grass.

Question:  I recently purchased two bougainvillea plants with lots of flowers from a local garden center.  My question is, “Should I repot or leave them in their original container.”  I have read much about not stressing their roots.  This is my first time buying bougainvillea and I don’t want to kill them.

 Answer:  The bougainvilleas will do just fine in their existing containers for a while.  However, if you wish to transplant them into a more ornamental like container, you can do so.  Just be sure, not to damage the individual plants rootball when doing so.

Question:  I have two seven year old Improved Meyer lemons that are not setting fruit this year?  The plants have an abundance of many beautiful, very aromatic blossoms, which fall off and are preceded by small fruit.  Why are my plants dropping their leaves?

Answer:  Typical citrus trees go through three distinct periods of fruit drop.  First is the drop of about 70 to 80 percent of the flowers during and immediately following bloom. The second drop occurs a couple of weeks later, involving small fruit of pea-size to marble-size.  The third drop occurs in late May, involving larger fruit, almost golf ball in size.  Navel oranges will drop again in mid-summer and in late summer.  A few fruit on all citrus will continue to drop through final harvest, but that is normal and cannot be prevented.

Question:  How do you know if a Pride of Barbados plant is dead or alive?  I have two plants: one is getting leaves from the bottom, and the other one has no leaves.  What do I need to do or how do I check to see if the plant is still alive?

 Answer:  Pride of Barbados will normally freeze to the ground each winter and will usually come back from the bottom.  Go ahead and cut everything off above the green leaves on the one and the other to the ground.  The one not showing any growth may just be a little slow or it may be dead.  You will know it is dead, if it doesn’t put on new growth within the next month.

 Question:  When we bought our property 8 years ago, there was a firebush plant next to the gate, with a juniper bush encroaching and overhanging into its space.  Thus, the poor thing hardly bloomed.  I want to move it into the afternoon sun where it has a better opportunity to flourish and bloom.

Answer:  It is probably surviving with a more extensive shallow root system.  Digging it to move will undoubtedly damage much of its root system and the above ground portion will need to be cut back severely to compensate.  If I were you, I would leave it where it is and purchase another to put in a more plant friendly place.

Question:  I live in an area with numerous deer and have several small pecan trees coming up from squirrel buried nuts.  Will they eat the young trees and do I need to cage the trees.  I would like to see the trees grow or just let nature take its course?

Answer:  You will need to cage the plants for several years.  Whether or not the deer eat the leaves will depend on how hungry they are.  However, the small saplings will not survive the buck’s habit of rubbing the velvet from his antlers.    

 Question:  Does the Shumard Red oak tree have a surface root system like a Live oak tree?  I like oak trees, but the surface roots of my very large live oak trees are NOT desirable.  What are your suggestions or recommendations?

 Answer:  The Shumard Red Oak has deeper roots than the Live Oak and will not normally damage driveways or other structures.

 Question:  I have a Live oak tree in my yard that was damaged from the drought last summer. I have had one dead limb cut off but it still has leaves on other limbs.  But yesterday, I noticed that a strip of bark, 6 inch wide and 6 feet high, is missing from one side.  Does this mean the tree is dying and should be removed?

Answer:  I cannot answer that.  The missing bark could be a symptom of Hypoxylon canker attacking the drought stressed tree.  If so, its recovery is very questionable.  I recommend that you contact the Texas Forest Service Urban Forester assigned to the San Antonio area.  His phone number is 210-494-4771 or email pjohnson@tfs.tamu.edu.

 Question:   Is it too late to cut back tropical hibiscus now.

 Answer:  While it would have been better to do it before they commenced their spring growth, you can still do it.  It will just delay blossoms a bit.

 Question:  My Texas Mountain Laurel trees haves red bugs (mite size) all over them.  Is this something to worry about?  The trees are well established and otherwise healthy.

Answer:  If they are in fact ‘mite size’, I wouldn’t worry about them.  However, it is likely that they are the immature larva of the Sophora bug (Lopidea major ‘Knight’) and will cause damage to the new growth.  This is purely aesthetic and causes no long term health problems for the plant.  They can be controlled by any insecticide labeled for bugs.

Question:  Do tomato plants like an acidic soil?

Answer:  The optimum pH range for tomatoes is from about 5.5 to 7.5 with 7.0 being neutral.  However, they are quite adaptable to most soils.

Question:  How do I know when my Irish potatoes are ready for harvesting?

Answer:  Irish potatoes are generally mature when the plant starts to turn yellow.  Potatoes require 75 to 140 days from planting to maturity depending upon variety and the season in which they are grown.  Immature potatoes will often skin and bruise easily.  When digging potatoes, if the skin is not set and is easily removed, delay the harvest.  Dig spring-planted potatoes before the soil becomes hot. Avoid harvesting the potatoes when the soil is wet to avoid potato diseases.

Question:  After harvesting, how should I handle my Irish potatoes so as to result in the longest storage time possible?

Answer: Dig Irish potatoes when the soil is dry, being careful not to skin or bruise the tubers.  Do not wash the potatoes.  Place them in crates or some suitable container and store them in a dark area for about 10 days at a temperature of 60 degrees to 65 degrees F. with a relatively high humidity.  After this curing period, keep the potatoes at 40 degrees to 45 degrees F. with the humidity near 85 percent and provide good air circulation.

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:  https://bexar-tx.tamu.edu.


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