1. Q. Last summer one of my trees was struck by lightning and later died. Was there anything I could have done to save the tree? How can I prevent lightning from damaging my other trees?
A. Lightning damages trees by heating cells along its path. Sometimes the cell sap is heated so quickly and so hot that an explosive burst of steam can cause additional damage such as ripping bark lose from the tree. This causes large water losses, so immediately take steps to prevent additional water loss. Remove damaged material and cut the edges of wounds so they are smooth. Apply pruning paint if a large area bark has been ripped from the tree. While current horticultural recommendations for normal pruning advise against the use of pruning paint, it would be appropriate to use it in this situation to protect a large area of cambium from insect damage and water loss.
If one side of the tree has sustained extensive damage, prune the healthy side of the tree as well to balance the tree and prevent it from toppling in the wind. Give the tree top notch care including watering and appropriate fertilization for the next few years to help it regain its health.
Lightning is most likely to strike the tallest thing in the area. Protect valuable specimens by installing a lightning rod in the tree.
2. Q: Client has two live oak trees planted three years ago. One of the trees is now shedding leaves. Why?
A. Shedding of leaves early in the fall means some type of root stress. It could be planted in a low area and overwatered. The period prior to the tree shedding its leaves was very dry so the homeowner could have underwatered if they were watering for short periods of time. It could also be caused by a broadleaf weed killer, weedeater. Seedling differences could be the answer.
3. Q: What is live oak wilt? What is oak wilt?
A: Oak wilt is a fungus disease of Live and Red Oaks. It stops up the vascular system preventing food and water from moving up the tree. More of a problem in central Texas, however it does exist in North Texas.
4. Q: How deep do you plant live oak acorns?
A: One-half times their diameter; however, depth is not critical. Placed up to 2 inches deep they will still do well. Critical factor is the acorn must be viable.
5. Q: When do you prune live oak's large limbs? When is best time to prune live oak?
A: Late winter to early spring; late February or early March when the trees lose and regain new leaves is the best time to trim. Major pruning in winter often shocks tree and it will lose its leaves. Dead limbs should be removed anytime during the year.
6. Q: Road and sewer work is being done on street and roots of oak tree are being disturbed.
A: If roots are cut back to any extent, prune tree to compensate for root loss. Fertilize in spring and don't let tree suffer during periods of no rain.
7. Q: What causes black spots on hackberry leaves?
A: It will be some type of fungal leaf spot but there is not enough information to be sure which one it is. Benomyl would probably control. Could be the start of sooty mold caused by aphids, scale, etc., if they are present.
8. Q: What is the life span of a hackberry tree?
A: Heart Rot, a disease that rots out the center of the tree usually kills them after 20 to 30 years. If kept healthy the tree will live a long time. In the
9. Q: What is the disease affecting sycamore tree?
A: Most serious disease of sycamore is called Sycamore Blight not Anthracnose although Anthracnose is common. If the top half of the tree dies it will be Sycamore Blight and there is no control. This is why we do not recommend Sycamore. Symptoms of Anthracnose are browning of the leaf which follow the veins.
10. Q: Why did leaves from mimosa tree turn yellow and fall during July and August?
A: Mimosa wilt, mimosa webworm or cultural problems such as water and heat.
11. Q: When do you prune a purple leaf plum tree?
A: Best to prune after the tree flowers in the spring if the flowers are desired; otherwise pruning can be done in late winter.
12. Q: When do you prune fruitless mulberry tree:
A: During dormant season. Best during mid to late January before new growth begins.
13. Q: Why are pine tree needles turning yellow?
A: Most probable cause is the variety is not adapted to high alkaline soil. Could also be other cultural problems such as lack of water, lack of sunlight, compacted soil.
14. Q: What is causing inside needles of a pine tree to turn brown?
A: This is probably natural leaf drop if coming from the center of the tree or natural shading from the outside needles.
15. Q: When do you fertilize trees and with what?
A: Newly planted and younger trees should not be fertilized at planting as it can damage new roots. If soil test shows need, use liquid fertilizer; however, entire area should have fertility corrected before planting begins. Established trees in yards that are doing well do not need extra feeding. They receive adequate fertilization as lawns are fertilized using a 3-1-2 ratio fertilizer. Lush, fast growth is not strong growth. Any heavy feeding should be in late winter for spring and summer growth; no special summer or fall feeding. So many symptoms of poor growth are cultural problems and feeding will not solve the problem only give a spurt of quick growth which the tree may not be able to support.
16. Q: What is the rate of growth of a cedar elm and how do you find one in the woods?
A: Moderate rate of growth probably 6 to 18 inches a year depending on culture.
17. Q: How should a banana plant be protected for the winter?
A: Cover with a heavy layer of mulch. The new growth comes from the base; i.e., a new shoot comes up each year.
18. Q: Where can you get Chinese Pistachio tree? How long does it live?
A: Any good nursery. They live 50 to 60 years.
19. Q: How do you kill a native cedar tree without cutting it out?
A: Girdle the trunk by removing the bark so transport of food and water is stopped resulting in the death of the tree.
20. Q: How do you plant a container grown tree that was root bound?
A: Advised to split lower half of root ball and spread roots horizontally. Remove any damaged or dead roots.
21. Q: Do roots of trees grow in winter and when do you fertilize trees?
A: Yes, roots grow in winter. Fertilize in mid-February.
22. Q: How do you treat an infestation of mistletoe?
A: Only solution is to cut back limb 10 to 12 inches beyond affected area. On large limbs cut a chip out of the limb into the vascular system where the mistletoe is attached. Refer to bulletin in bin 1228 "Mistletoe Control".
23. Q: When do you prune a palm tree that is getting too large?
A: Palms are difficult to prune. If plant is too large for area need to remove and plant a smaller one.
24. Q: When is Arbor Day? Has date changed?
A: Date has changed. For 1990 and the future the date will be the last Friday of April
25. Q: When should you prune trees and shrubs that appear to have been damaged by the freeze?
A: Wait until after new growth is well started; probably late March through April depending on the weather. Determine the damage then cut back to healthy growth. Refer to bulletin in bin 1203 'Pruning Ornamental Trees and Shrubs".
26. Q: What are the growths on the underside of leaves of a hackberry?
A: They are called nibble galls. They are harmless.
27. Q: Should the roots of an Arizona ash that are lying on top of the ground be removed?
A: Yes, but only remove one root each year.
28. Q: Is bald cypress a good tree for this area?
A: Yes. Excellent.
29. Q: Is it necessary to prune a red oak?
A: No, unless there has been some limb damage or there is a need to raise the height of lowest limbs.
30. Q: Live oak tree has balls on branches that are about one inch in diameter.
A: These are galls that are the result of insect stings. They do not cause any harm to the tree.
31. Q: What causes a Bradford pear tree to loose its leaves in the hot summer?
2nd question: Bradford pear leaves are turning yellow with black dry edges; what is cause.
A: Severe drought stress could cause such a problem.
32. Q: Is there any way to make a Bois d'Arc tree not bear fruit?
33. Q: A hackberry tree has a hole in the trunk at the "Y" of a branch. Hole has watering standing in it. Can it be closed with concrete?
A: Clean out the hole and remove any decaying wood. Be sure it is dry; then fill the hole with tar or concrete to seal and cause the water to drain away.
34. Q: A Silver Maple tree's bark keeps coming off in big chunks. Tree is 10 years old, 10 inch diameter and 50 feet tall.
A: Peeling bark on older Silver Maples is a normal occurrence.
35. Q: There are small holes in a straight line around the trunk of a live oak tree. There are small worms (larvae) in the bark.
A: Holes are caused by woodpeckers that are after the worms.
36. Q: The roots of big trees are coming up above the grass. Should these be cut off?
A: No. This is normal for some varieties of trees and root removal could damage the tree. Over a period of time minor roots could be removed a few at a time but not major ones.
37. Q: How close to a driveway can you plant photinia shrub and a live oak tree?
Can you pave over roots of a live oak?
A: 5 to 6 ft for photinia, 15 to 20 ft for live oak.
38. Q: Will a blue spruce grow in this area?
A: No. It is not recommended.
39. Q: How can you germinate seeds from Texas Mountain Laurel?
A: Seeds are bright red, beanlike, and are extremely poisonous. Seeds need to be scarified to germinate; that is, shell of seed needs to be broken. Could try some seeds by scarifying and others without; then place between wet paper towel in plastic bag in a warm area such as above a hot water heater. Check in 24 hours for germination.
40. Q: Should you prune a bald cypress tree?
A: No, unless to raise the level of bottom branches or to remove rubbing branches.
41. Q: Can you raise the soil level under a magnolia tree enough to plant Asian Jamaine?
A: Soil should never be increased more that 2 inches under trees and added soil needs to be more porous than the existing soil.
42. Q: Will ivy growing on trunk of tree damage it?
A: Ivy should be trimmed to keep it out of tree branches. Avoid watering tree trunk which could cause rot.
43. Q: Leaves of magnolia tree are mottled, turning brown and dropping.
A: Magnolias naturally shed last years leaves and replace with new leaves.
43. Q: The bark on a pecan tree has vertical piece loose due to growth or rain. How should wound be fixed?
44. Q: Will a bald cypress tree continue to put out "knees"? If the knees are cut out, will it damage the tree?
A: Any wounds harm trees and makes places for decay to start. "knees" are usually associated with overwatering. Back way off on the water and they will not return.
45. Q: Does a Texas Mountain Laurel and a Muscal bean tree grow here?
A: Both are the same tree. They can be grown here but do freeze back in hard winters. They like well drained soil. Tree is better for Austin area. It would be better to plant the close relative, Eve's Necklace (Sophora) here.
46. Q: Do all Bald Cypress have knees?
A: "Knees" on Bald Cypress is a symptom of over-watering. Properly watered trees do not get knees.
47. Q: Client has sprouts coming up under a live oak tree. They believe these to be from acorns. Can these sprouts be treated with a herbicide and not hurt the live oak tree?
A: These sprouts could be from the tree roots. Would need to make certain they are from acorns before treating. Better to cut off 2 to 3 inches below ground level.
48. Q: A redbud tree was transplanted but the limbs were not trimmed back. Can they be trimmed back now?
A: If they are holding leaf, leave them. This increases the food being made and helps the tree in all situations. Normally, redbuds are trimmed after spring bloom.
49. Q: How do you get rid of live oak seedlings that are coming up in the lawn?
A: If they are root sprouts, cut them back and do not use a herbicide.
50. Q: A live oak tree has large roots out of the ground. Can they be cut off?
A: First need to be sure it is a live oak. It is unusual for roots of a live oak to come to surface. They could be removed one at a time, one each year.
51. Q: Can you remove the surface roots of a redbud tree?
A: Removal of roots should be done carefully as redbuds are prone to borers. Any stresses set them up for infestations. Removal of roots is not recommended under most circumstances.
52. Q: How do you treat a tree for fireblight?
A: Prune well beyond infected limbs and destroy. Streptomycin compounds sprayed when 3/4 of flower petals have fallen helps prevent spread of disease.
53. Q: A newly planted live oak is loosing its leaves?
A: Probably transplant shock. Need more information to complete the answer. Was it balled and burlapped or container grown? Was it purchased from a reliable nursery? Was it loosing any leaves before it was planted/ how long before it started loosing leaves?
54. Q: Why is the bark coming off a sycamore tree:
A: Natural occurrence as sycamores have exfoliating bark.
55. Q: What is the best time to trim and prune an elm tree?
A: During the dormant season, probably January.
56. Q: There are gray patches on the bark of a pecan tree. It is also on various other trees in yard. In some places it is almost solid and all the way around the tree trunk. It is powdery when you scrape it off. All the trees are touching one another.
A: It is lichen. Don't worry it doesn't harm the tree.
57. Q: How do you fix a cavity in a tree trunk?
A: Most cavities need a solid surface for callus to form over. Get it dry and fill with expanding insulation foam.
58. Q: How best to get rid of an unwanted hackberry tree?
A: If possible, call professional tree removal service. If this must be a 'do-it-yourself' project, cut the tree down as near as possible level with the ground. Drill holes in stump and pour in broadleaf weedkiller. Will undoubtedly need repeated applications. Root shoots will probably be a problem for some time. Paint leaves of shoots with broadleaf weed killer.
59. Q: Would 6 to 7 foot diameter raised soil beds around the trunk of large trees, but not touching the trunks, harm the trees?
A: If the new soil depth is no more than one inch, there probably would be no damage to the tree. Any greater depth would shut off natural oxygen supply to root structure.
60. Q: A chinaberry tree died but the stump continues to send up sprouts. Has used several chemicals, but none appear to kill the stump. Need recommendation.
A: Broadleaf week killers will kill tree sprouts. Use as they appear.
61. Q: Will the roots of a cottonwood stump that has been removed and ground out sprout?
A: They often do. Use broadleaf weed killer on them or kill stump before grinding.
62. Q: Will a bald cypress grow in a well of water?
A: It will stand the best channce of any tree but it may be difficult to get it started.
63. Q. I enjoyed hearing you discuss control of the ball moss which grows on live oak limbs. What was the name of the product which you said should be sprayed on in February-March to kill the ball moss?
A. The product is named Kocide 101 and it should be applied at the rate of 4 pounds in 100 gallons of water. If you are going to treat large trees I recommend you rent a tank sprayer available at some rental places. Kocide is a blue product which will not stain bricks or concrete as will iron sulfate but will discolor what it comes into contact with for a period of time. Moss will not immediately fall from the tree but deteriorates over a period of time. Severe infestations may require multiple applications over a 2-3 year period.
64. Q. Do plants normally wilt after prolonged periods of rainfall. I have notice some of my shade trees are dropping some leaves and several of my fruit trees died in a short period of time. Did the excessive rains cause this?
A. Most fruit trees and some shade trees are very sensitive to wet soils. Excessive rainfall will cause serious root injury to peaches, red oaks and other plants -- especially where they are growing on poorly drained soils. Roots require oxygen to live and grow and water-logged soils can cause root death from oxygen starvation and related gas exchange problems. Trees or shrubs suffering from water damage usually leaf out and look normal for a few weeks and then they begin to weaken as leaves yellow and drop and/or wilt. Stored carbohydrates in the above ground portion of the tree will usually sustain root- injured trees for a few weeks in the spring (the bigger the tree the longer it may last) before they begin to show leaf stress, wilt, and possibly die.
Trees that lose part, but not all of their root systems may be able to make it in the spring, but then often succumb in the hot dry summer months.
The excessively wet soils can also trigger root disease problems such as Phytopthera sp. Phytopthera root rot will kill many plant species, including peach and apple, by girdling the base of the trunk a few inches below the ground.
Recognize water damaged or root-diseased plants that die by a lack of suckers sprouting from the trunk. Plants with top kill from other sources will usually generate sprouts from below the injury since the root system is still healthy.
65. Q. Something is cutting the tips of my oak tree branches off. The twigs which fall look as if they were cut with a knife. What is doing this and what can be done to prevent it?
Q. Something is killing the tips of my oak tree branches. There are dead spots or limb tips scattered throughout the tree. What is causing this and what can be done to prevent it?
A. Twig girdling insects and twig blight are causing the diebacks which are concerning you. There exists no practical cure for either affliction. You could apply a weekly application of insecticide for the twig girdling insect and you could apply a weekly application of a fungicide for the twig blight. Both cures are not necessary. The tree will endure and, in fact, prosper since the tipping back of growth by girdlers and blight stimulate lateral growth and more dense foliage.
66. Q: Is it possible to grow olive trees in Texas? The area of the state that I am interested in is near Blanco (sorta between Austin and San Antonio).What is the cold and salt tolerence of olive trees and what varieties produce usable fruit?
A: Olive culture in Texas is experimental at best. They are essentially a mild climate plant, yet they require a cold requirement in order to flower and bear fruit. In most areas of Texas where they get enough cold to fruit, they often freeze to the ground in 2 out of 10 years. In areas where they don't freeze, they usually don't get enough cold to fruit.
We are currently watching some new varieties to see how they perform. The potential site you have selected is actually a pretty good site as for as climate goes.
| Parson's Archive Home | Aggie Horticulture |