Xtremehorticulture

Tree Selection After Winds Toppled a PIne Tree

Q. My large Pine tree blew over. In researching on line I find there are lots of options to replace it. Most have con’s but I like the African Sumac, Raywood Ash, Weeping Willow and Poplar Trees. Please send me your recommendation on these or any other one recommended. I live in Mesquite, NV. A. Definitely not weeping willow or poplars. The other two are okay. Weeping willow is a very short lived tree in our hot desert and may last ten years if you are lucky. It needs to be next to a lake or river. Poplars of all types and weak and break easily in winds and very very messy. If you have some others you like then run them by me and I can give you a thumbs up or down. This is a good site to help you in your selection. Maybe someone out in that area has a favorite? https://www.snwa.com/land/design_plants.html

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Random Thoughts Regarding the Desert and Our Hot Summer

Perhaps this summer has been brutal but plants like palo verde can handle “brutal” weather.   “Native” palo verde in Arizona in bloom Be careful how these plants are pruned. The tendency is to prune them too high and this removes the shade that the tree naturally provides the trunk and limbs. Watering also helps. Plants like palo verde respond very nicely to increases in applied water very quickly..in just a few days. Water these plants with a hose to give them a shot of water and improve shading of the limbs and trunk.    Sap coming from Palo Verde. Removing too many branches and exposing too many large limbs and the trunk can lead to sun damage of this thin barked tree. Hopefully plants like palo verde were not pruned to allow excessive sunlight to shine on the trunks and limbs. Also, water in the soil helps keep limbs and the trunk from burning because these areas release water to the air and help cool the limbs and trunk through evaporation of water from microscopic holes that can open and close called stoma or sometimes called stomates. If water is restricted it cannot cool itself properly and they will burn. OR water loss can be faster than the plant can replace…as in the case of apple fruit…and burning occurs. That is a wide variety of plants to have sunburn on. Sunburn on trees is usually restricted to trees with a think bark (palo verde fits this) and a lack of shade covering the limbs and trunk. Sunburn is on the sides of the trunk and limbs that face the sun and not on the other sides in the shade. If this damage extend into the side in the shade then it is something other than sunburn that is going on.    In my opinion too many of the lower limbs were removed on this Palo Verde which can lead toward sunburn You can apply the same logic to agave and desert spoon. Not enough water can contribute to sunburn. If they are droughty then will burn more easily than if they are getting enough water.  A lack of soil improvement…poor soils that were not improved by adding compost at the time of planting…YES, this includes cacti!…may sunburn or turn yellow from intense sunlight. Sunburn comes in different degrees of severity…mild sunburn is a yellowing of leaves or fruit but not death of the plant tissues  beneath the damage. Medium damage results in yellowing with some brown or tissue death in or near the center of the yellowing…there is tissue death and this tissue death will attract bugs and other critters that sense the plant is damaged.  Borers will attack sun damaged areas on the trunk and limbs of trees These are bugs that are “decomposers” who want to break down these damaged plants and “recycle” them…naturally. The third stage is death of the tissues facing the sun, not only brown but cankered with bark or the skin dead and scaling or peeling back. This makes a pretty ugly plant. But the sides away from the sun are not damaged and the plant will survive unless some “decomposers” get in their and try breaking them down by feeding on them. Borers are in this category. They are goners if they look bad enough you cant live with them any longer. In most cases they will survive.

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Pollenizers for Fruit Trees Can Be Region Specific

Honeybee collecting nectar and in the process pollinating a peach flower Q. We purchased a Fuji apple tree from Nursery and the tag says that they are self-fertile. Everything we see on the internet says that is not so. Internet also seems to indicate that a crabapple is the best pollinator overall. Wondering if there are dwarf crab apples available that would pollinate because our backyard is crowded. A.  A comment on terms. Just fyi, and I make the same mistake, pollinators are insects like bees and moths. Pollenizers are trees needed to set fruit.             Little-known fact is that pollination is region specific and we can’t follow the rule that “one size fits all” regarding pollinizers for fruit trees. A very good site to reference for our area regarding whether a fruit tree needs pollinator or not is the Dave Wilson Nursery website found at www.davewilson.com  Look up Fuji apple on this website and it will tell you what pollenizers are needed, if any.             Dave Wilson nursery is a commercial, wholesale fruit tree nursery that sells to retail nurseries and orchards only. They provide excellent educational information on their website courtesy of Tom Spellman who works for them.             The information I have also is that Fuji does not require a pollenizer in our area. I know Tom and he checks in my blog occasionally and maybe he will comment there as well. Some fruit trees will set fruit without a pollenizer but set a heavier crop with one.             This can be sometimes good and sometimes bad because of thinning or removing the fruit to get larger ones.

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Snail and Slug Control in the Garden

Q. I live in Las Vegas on a 1/2 acre lot with a large back yard. My #1 enemy is small grass snails that destroy the roots. Is there a product that you know of that will eliminate these pests?  FYI, we also have a desert tortoise, and dogs and would not want to harm them.  These are pictures from other readers in the past regarding snails A. Here are the options as I understand them for snails and slugs. Basically, slugs are snails without the shell so they are treated about the same. Sluggo. This is a commercial bait that is advertised as safe for pets. It is a combination of iron and phosphorus but concentrated. Apply every two weeks around plants and the soil should be moist but no standing water. Since they come out at night, apply it at dusk. Newspapers and cardboard. Lay wet newspaper and cardboard on the surface of the soil between plants where there are problems with snails and slugs. In the morning pull up the newspaper and cardboard where you will see them having a party. Put on your party hat, collect them and dispose of them. Stale beer. I like Heineken for myself and Blue Moon in the summer but snails and slugs are less picky. Any old cheap beer will work. Open some cans of beer and let it sit for one day to get stale. Pour it into shallow dishes in the garden and they will come in there again, to party. In all of their excitement they drown in the stale beer. Collect them, dispose of them and put more stale beer out. Aluminum foil. I have been told that a ring of aluminum foil around plants will keep them from getting to them. I have never tried it. I don’t like adding table salt to the soil or critters which I have seen recommended in the past. Maybe some readers have some good ideas. Let’s let them comment on my blog about this.

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Chinese Pistache Trees with Verticillium Wilt Disease?

Q. We have two Chinese pistache trees in our backyard that appear to have verticillium wilt. Any suggestions? A. How did you confirm this disease? Do you have isolated branches that are dying back? It is rather rare to have this disease in a home landscape. Not impossible, but rare.If you are correct than this could impact your entire landscape and future plant selection.             I am sending you a link so that you can look at pictures of this tree when it has verticillium wilt. Readers can also see this link on my blog.  http://ipm.ucanr.edu/PMG/r605100811.html             There is not much that you can do if you in fact your trees do have verticillium wilt. It is fairly easy to diagnose if you know what to look for.             All you can do now is make sure the trees are not getting too much water, not fertilized with too much nitrogen and prune out the infected limbs.             This disease is in the soil so planting in this spot with susceptible woody trees is not a good idea. You can use ornamental grasses and pines in this spot since they don’t get this disease.

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Mulberry Trees Are Very Tolerant of the Desert but Have Their Problems

Q. I would like to replace a huge Mulberry tree in my front yard, roots are very invasive but the shade is wonderful. We have west facing home. I would like to replace with a small bay laurel for cooking purposes and a shoestring acacia for shade. Are these trees invasive and would both be too much? Mulberries planted in home landscapes are usually male trees and these trees produce pollen. Mulberry is very tolerant of many types of soil and high temperatures. It is a great shade tree for the desert because it can produce 100% shade. But it also has many problems for communities in the desert. Mulberries are normally shallow rooted. They don’t typically have a deep root system even under the best conditions. Mulberries flower in the very early spring before the leaves emerge. Some mulberry trees are male and others are female. The male trees produce pollen which many peopl are allergic to and the female trees produce fruit which can become very messy. A. Invasive has several different meanings. If you mean, are the roots in they? Yes, Mulberry has a very invasive root system. Mulberry is a great tree for the desert if you are just talking about how easily it handles extremes of all kinds and produces 100% shade if it gets enough water.             But it does have a lot of problems; very high water use, the mail tree produces a lot of pollen that can be a human health hazard and the roots will get into any place where there is water and nutrients.             But that goes for almost every tree that’s out there including many of our desert trees like Acacia and Mesquite. If given the chance, Bay Laurel will have an invasive root system.             You will want to keep all trees added distance from the house and other structures including walls that is half of its mature height. Never plant them on top of a septic system, near a swimming pool or near the sewer lines.             I think planting Bay Laurel in a Western exposure could be a mistake. It will do much better on the north or east side of a home with some protection from the late afternoon sun. As a warning to you, I have seen freeze damage to Bay Laurel in the Las Vegas Valley.             I would try to put it in a spot that has some protection from strong winter winds. The Acacia will handle a Western exposure very nicely. However, it will not give you the same shade as a Mulberry. I think you could classify the Acacia as filtered sunlight which will allow you to plant beneath it. Planting under a Mulberry tree has a lot more restrictions because of the dense shade.

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Shrub Dropping Its Leaves Could Be Lack of Water

Q. A month ago we had a shrub that was seemingly healthy.  It began losing its leaves since then.  I do not know the name of this shrub but it is ten years old and planted on the north side of our home getting only the early morning sun. My question is, is there a possibility of the leaves coming back or is this shrub a goner?   A. Couldn’t tell 100% from the picture you sent but I think it is Pittosporum. First glance at the picture looked like it went through some sort of rapid shock. That’s why there is leaf drop and many of them are still green. Otherwise, the plant looks healthy except for this leaf drop.             I think the soil got too dry for a short time and caused the leaf drop. Take a hose and soak the area at the base of the shrub twice during this next week. I think you will see it produce new leaves and start to come back within 7 to 10 days.             Check to make sure the drip emitters are not plugged and the plant is getting water. But I think it was a short-term water problem during excessively hot weather.

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Tall Fescue Lawn Suffers from Summer Patch Disease

Q. This is my fescue lawn. Bugs or fungus and how do I eradicate? I had a similar problem last summer. Thanks.   Readers picture of lawn disease problem.   This is typical of a summer patch disease problem and the patterns it creates in the lawn. See that dead grass surrounds green grass. It used to be called “frog eye” for this reason. A. David. This looks like Summer Patch disease. Common on tall fescue here starting about June during the heat. Notice how the edge of the dead spot is well defined. The attack is over it looks like. Now you are left with dead spots. Mark your calendar when it pops up generally. Usually this is at the time of “summer monsoons” when the humidity increases. Apply a fungicide for lawns that says it controls summer patch at this time. Fungicides are mostly preventive in nature. They help the spread of disease but often times does not correct the problem. You will protect the lawn with a fungicide according to the label until this summer monsoon season is over. Wait until Oct 1 and then rake up the dead areas and mow the lawn in that area short. Spread a good quality fescue seed and topdress it lightly with topdressing and water lightly daily until it germinates. Once it germinates then reduce watering gradually until you are back to your normal irrigation cycle.

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