GARDENING: When in doubt, compare area trees for healthiness
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Question: I have two olive trees in my front yard. I noticed that both trees have brown blotches on the trunks. The areas range from 10 to 12 inches to over 24 inches long and 3-4 inches wide. They are irregular ovals. No oozing of sap that I can tell. I have not changed any watering schedule and have not sprayed or fertilized. The best way to describe it is that it looks like a bruise on a banana. Also kind of looked like how my roses looked when they got borers. These trees are 10 years old and I really want to save them.
Answer: From your description I don't think they are anything to worry about. I believe it is natural coloration from being exposed to our climate and weather. We have very few problems with olive trees and none that resemble your description. If the tree looks healthy, it probably is.
When you are unsure about something you see on a plant and you get worried about whether it is a disease or insect problem, take a look at other plants of the same type in your area. There are lots of very interesting and unusual features that plants have which can look like possible problems. But when we look at the same tree in another person's yard we see that it has the same feature there as well. We can then rest assured that it is just a natural feature that makes this plant unique.
Other examples are the flaking or exfoliating bark of some trees like sycamore and crape myrtle as they age. I frequently get asked if this is a problem since the owner did not see this feature when the tree was younger.
Make sure your tree receives deep watering at times, fertilize once a year and prune to thin out the canopy, but leave the canopy full and shading the trunk as much as possible. Do not have it limbed up or cut off the branches by topping. When pruned correctly it should not look like it has been touched.
Q: Considering temperature in Las Vegas gets into the 20s during the winter, when is the best time of year to plant dwarf oleanders? And among the red, pink, apricot and white versions, which is the hardiest ... or are all about the same?
A: To my knowledge dwarf oleanders are all about the same in low temperature survival. I have not seen many dwarf oleanders except salmon colored. As far as common oleander or standards, they are all about the same in cold temperature survival, about 10 F. Dwarfs are about 25 F. Mulch the bases if temperatures drop to freezing on the dwarf. You might want to consult this Web site on oleanders www.oleander.org/varieties.html.
Q: I am considering planting two Ficus nitida trees in my yard for shade. I like the idea of no leaves in the pool. I can't find any real information on size, growth-habit, care, etc. Also, is this a good time of year to plant these trees. Actually I won't be able to plant until the first week of November.
A: This plant also may be called the Indian Laurel Fig or in tropical countries it might be referred to as the Banyan tree. These get to be spectacular trees where they can grow to their fullest with roots that stick out of the ground (aerial roots) like a bald cypress.
After saying all that, I would not recommend Ficus nitida here for any job in the yard where you are looking for a long-term solution. I guarantee that it will not be a long-lived tree that you can rely on. Any frost at all in the Las Vegas Valley will cause it to lose most of its leaves. Temperatures dropping to 25-28 F will kill it to the ground. It may resprout if mulched and grow rapidly again but any low temperatures here will be its doom.
It would be okay for Phoenix, Lake Havasu, Palm Springs, but not here or anywhere like Las Vegas or colder. There are even a few in Tucson in protected locations. This plant is native to Borneo. If you want to have fun with it with no long-term expectations, then go for it!
Q: I am hoping to find a tree with that full, lush look for shade. It is also close to a pool. Tall is good, as I'm trying to shade my son's play area, and the lawn in the backyard. So dense shade is OK. Do you have any suggestions?
A: There are so many to choose from it's difficult and then there are personal preferences. If you have time, I would visit the Desert Demonstration Garden and take a look at what they have on display. You also can visit our office and see some of the trees in our reference books with our Master Gardeners, any Monday through Friday from 8 to 5.
You know, seasonal shade is nice in the hot and cold deserts and if you get a tree with relatively large leaves they are easier to clean from a pool. Stay away from pines and palms near a pool due to their needles and seeds.
Some of the faster growing trees are African Sumac, mesquites and acacia. Also physical structures such as a gazebo or covered area with vines are a nice alternative to a tree and get shaded much quicker. You might be looking at getting shade from trees by the time your son is interested in girls and doesn't want to play back there anymore!
If you can narrow the selection down to five trees I can help you from there with pluses and minuses.
Q: Last spring I purchased fresh basil packaged with the roots. I planted it and left it inside but in indirect sunlight. But it really did not pick up or thrive well. So I moved it outside on the little porch we have at our apartment complex and was able to keep it in indirect sunlight. It grew beautifully with huge leaves. The bugs loved it. Little bugs. They almost reminded me of fruit flies only much more hardy. And, they almost seemed to hop-fly. They were throughout the soil even! They make holes in the leaves. This bug infestation occurred later spring/early summer. I tried the organic spray made of soap and water. Organic references told me to use basil as a repellent for bugs! Do you have any suggestions for keeping basil bug-free but still edible?
A: The usual bugs that are problems on basil include fungus gnats, whiteflies, leaf miners, thrips, and flea beetles. Every plant has its problems, even when they are recommended to repel bugs!
I think the flea beetle may be your problem judging from your description. Flea beetles, as their name suggests, jump and love wet soil preferring plants growing in shade. They can be different colors including striped. These guys can cause damage that resembles your description.
Fungus gnats are small, usually gray or black which fly or swarm like mosquitoes or fruit flies when the pot is disturbed and about the same size. They will feed on roots when abundant. They cause the plant to struggle but no holes in the leaves.
Whiteflies are, like their name suggests, white, fly and about the same size as fungus gnats. Kind of remind me of flying dandruff. They swarm when the plant is disturbed. They feed on leaves and cause leaf curling and drying. No holes in the leaves.
Thrips are very tiny flying bugs. Thrips can be difficult to see if you need reading glasses. They rip plant leaves and flower parts with their mouthparts and don't leave holes. They will cause scarring of plant tissue and usually drying of leaves.
Others include leaf miners that cause brown or pale streaks (tunnels or mines) in the leaves, grasshoppers and some flying beetles that chew leaves, slugs that you may see only at night or early morning/dusk hours but can see their slimy trails they leave behind and mites that cause leaf spotting and are usually a problem when it gets hot but don't sound related to your problem.
I would recommend protecting your plants with Neem early in the season and repeat sprays when you see holes beginning to appear. Another possibility would be to use pyrethrums, a derivative from the pyrethrum plant. Be sure to read the label and it will tell you how soon you can harvest and eat after spraying.
Bob Morris is a horticulture specialist with the University of Nevada Cooperative Extension.
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