Xtremehorticulture

Xtremehorticulture of the Desert

Please Dont Prune Your Palo Verde LIke This

6 Comments / desert, Las Vegas, Mohave Desert, Mojave Desert, nevada, pruning palo verde, topping, trees /

I was dumbfounded. I saw it from the bus. I take the bus to the Orchard in North Las Vegas up Decatur when I go there to teach or just volunteer. I got off the bus and walked over to this tree because it was sooo obvious. What in the world was going through this person’s head? A beautiful tree and its form butchered. The tree could have been pruned with fewer cuts and not so much to clean up after you were done. This will take years to correct by a competent, skilled tree worker. Some say “arborist” but there are skilled arborists and unskilled arborists. There are skilled tree workers and unskilled tree workers. There are skilled gardeners and unskilled gardeners. Some of the best tree work I have seen was done by an indvidual (now passed) many years ago who had no training (at the time) but was sensitive to the look and needs of the tree. He went on to become an excellent arborist. (Steve Hines where are you?) Heading cuts. The cuts made at the very top are what I call “heading cuts”. They were made anywhere  along the length of a branch. When this is done we call this “topping” a tree. This is not a good idea for many reasons. From the looks of all that growth at the top, the tree has been topped at least one other previous year. Pruning in the spring invigorates the tree. One heading cut results in three to four new stems growing from buds immediately beneath the cut. One cut branch now = 3-4 new branches that need cutting next year. When topping is done the new growth is prolific. This prolific growth shades the interior canopy resulting in death of branches inside where there is too much shade. Thinning cuts. Cuts lower on major limbs on this tree were made with what I call “thinning cuts”. Thinning cuts are made at a juncture of two limbs leaving one limb remaining. This type of cut should be made 95% of the time when we prune. Thinning cuts leave another branch to take the place of the one just removed. This helps decrease the amount of new growth we get from pruning. This type of cut helps retain the natural form of the tree. Determine what you want the tree to do. What do we want from the tree? Is it to give shade? Will people walk under the tree? Does the tree need to be shrunken in size? What we expect from the tree dictates how we will prune the tree. Prune with a purpose in mind. The right approach to pruning a tree like this is to start at the bottom and work up. Make sure the major limbs are necessary. If there are too many, you might consider removing a major limb at the very beginning. This is true particularly if there are just too many larger limbs, if they are crossing, broken or damaged. If the tree needs to be shorter then identify the limbs that need to be lowered and follow them down inside the canopy to a place where you can make a “thinning cut”. Lower the tree’s height be identifying each of these limbs that are too tall and reduce their height with thinning cuts. If the tree is growing toward a building or structure then remove limbs growing in that direction or that will interfere. Make the cuts using what kind of cut? That’s right, a thinning cut, not a heading cut. If we need to allow people or vehicles to pass under the tree identify the offending branch or branches and remove a portion of that limb with what kind of cut? That’s right. A thinning cut. So when do we make a heading cut? Not very often but when we do it is usually for three reasons: increase the density (more new growth; 1 cut=3 to 4 new branches) where the canopy is not dense enough, to add dimensional strength to a limb that is thin and spindly, to increase side branching to increase fruiting or flowering on trees that produce flowers/fruit on spurs. A correctly pruned landscape tree should not appear to be pruned when it is completed and done right.

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Pick Fruit and Check for Circling Roots When Repotting Lemon

Leave a Comment / citrus, container, desert, girdling roots, Las Vegas, Mohave Desert, Mojave Desert, nevada, planting, pot bound, potbound, replanting /

Q. I purchased a lovely Meyer Lemon tree in a one gallon pot in middle of the spring. It already had 6 lemons on it. I have the original fruit, have new fruit growing, and still am getting blossoms. Should I transplant it now into a larger pot or wait until after the fruit ripens and is used? A. Remove any mature lemons from the tree.  Lemons should not remain on the tree longer than about late December and possibly early January at the very latest.  Check for circling roots in the container before planting. This is early enough you might be able to correct it.             Leaving lemons on the tree can disrupt the flowering fruiting cycle for the next season.            If you are planning on putting it in the ground then I would just wait until you have that spot prepared if it is this spring. If you are planting this fall then you might want to repot it into a larger container and wait for fall planting. When circling roots get to be this far along they can no longer be corrected.             If you do repot, check the roots for circling inside the container. This is a common problem in nursery grown trees, called “potbound”, sold in containers. Planting a tree with roots circling in the container and not trying to fix this problem before planting can lead to some serious problems down the road.

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Do Liners at the Bottom of Raised Beds Help or Hinder?

1 Comment / desert, Las Vegas, Mohave Desert, Mojave Desert, nevada, raised beds, vegetable garden /

Q. I’m setting up some raised beds for planting this spring and wondered about water evaporation from the soil. Since water retention in the soils here in Vegas is an issue due to the heat would it make sense to put a liner in the beds to help keep the moisture from draining out so quickly? A. No, I would not do that. Water will drain to the liner and begin to puddle or “perch”. You need continuous movement of water through the soil to prevent your raised bed from staying too wet above the liner. Raised bed under construction with cement side walls against a block wall.             In the Las Vegas Valley, water originating from the Colorado River carries significant amounts of salt. Our soils also contain large amounts of salts. Some are good salts and some are not but regardless we must keep these salts moving through our soils.             The best way to do this is to “overwater” our soils to flush salts through the soil. The overwatering does not have to be much, maybe 15 to 20%. But this 15 to 20% has to go somewhere.             To keep these salts moving or eliminated from our soils we have to make sure water leaves raised beds and goes somewhere. A liner at the bottom of the bed slows down this “flushing” action.             If you are going to put some sort of barrier at the bottom make it porous so water can move through it.

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Remove Suckers Coming From Rootstock on Loquat

Leave a Comment / desert, Las Vegas, loquat sucker, Mohave Desert, Mojave Desert, nevada, pruning /

Not sure if I should remove growth below the graft from a Loquat tree. Q. I have a loquat tree that is a few years old. I let it grow without any pruning so far. I did notice one of the branches growing from beneath what appears to be a graft union. Normally I remove any growth from below the graft as I do on my other fruit trees.  That particular branch has new growth just starting.  I was hoping this branch would give me the balance I needed since it was growing outward where there is an open space. Not sure if I should cut growth below the graft from a Loquat tree. Sucker coming from rootstock on loquat. You can see the bud union above it. A. From the picture you sent to me I can see this sucker is coming from the rootstock. Loquat is normally grafted on to a rootstock that is either not a loquat or the rootstock plant is inferior in fruit quality to the one you purchased. Very healthy young loquat             This sucker must be removed. Even if you could keep it, how it is attached to the trunk is weak and will split from the tree when the limb gets heavier from fruit or size. Fruit of loquat             Loquats do nicely here and have some great fruit. Try to keep it out of late afternoon sun and don’t prune it too much so that the canopy is open. It will sunburn and you will have borers in the tree.

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Repairing Lemon Trees From Winter Cold Damage

Leave a Comment / citrus, cold damage, desert, freeze damage, Las Vegas, Meyer lemon, Mohave Desert, Mojave Desert, nevada /

Q. Our lemon tree shows damage after our recent very cold spell.  Some of the leaves are dry and dropping.  Is there anything we can do to assist the tree? A. The damage can take several different stages. The degree of damage depends on the lowest temperature reached, the amount of time at this temperature and the source and condition of the plant.             The first stage is slightly below its tolerant range and results in leaf damage and other soft tissue death while the stems remain relatively undamaged.             The second stage is at temperatures slightly lower or held for a longer period of time. This results in leaf damage or leaf drop and death of smaller stems.             The third stage is complete death of the limbs and trunk back to the rootstock. The rootstock is normally a very hardy citrus grafted on to the more tender citrus.             In this third stage the more valued lemon portion of the tree completely dies but leaves behind the more cold-tolerant rootstock. When temperatures warm, the rootstock will sucker into a totally new, but different, citrus tree.             You can get some idea now by bending some branches and see if they are supple and bend or if they snap off. But you will not really know the extent of the damage until you see new growth in a month or so.             Once you see where the new growth is coming from you can make a decision to keep the tree or remove it and start all over. If you have suckering from the limbs then you might want to prune it back and let it regrow.             If suckers just come from the roots then it would be wise to remove it.

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Ornamental Pear in Bloom Now… A Nice Tree Where it Has Room to Grow

Leave a Comment / bradford, desert, desert landscaping, Las Vegas, Mohave Desert, Mojave Desert, nevada, pyrus, tree selection /

The good and bad about ornamental pear in the desert. I get questions very, very often about which plants I recommend. I am sorry. But I really hate that question. Half of the answer involves will it grow here and how difficult is it to grow AND the other half is the homeowners personal preference. I have no problem with the first part. It is the second part that is really difficult for me to get a handle on. Because it is a personal question. Ornamental or Callery pear. The Good. Ornamental pear, sometimes called Callery pear, has been around in several different forms for a long, long time. I have been watching them here in Las Vegas for nearly 30 years in different locations and surprising to me they really handle alot of adversity. They can handle rock landscapes, droughty conditions, poor soils, lawns and has few pest problems, unlike in some other places. It is a good choice as a street tree and parks. The Bad. I would not recommend it for home landscapes unless you have a fairly big landscape area and it is probably best if you have a two-story home, not a single-level in terms of size. It can get a bit big if well cared for, 40 feet in our desert. Although I have to admit I have not seen one get that tall here. It is not low in water use. Just like any other fruit tree its water use will be moderately high and increases proportionately as it gets bigger. It will perform better in soils improved with compost and covered in wood mulch rather than rock mulch. It can get a some fireblight (bacterial disease) some seasons if it is raining at the time of bloom (February here). It does produce fruit but it is so small it is mostly inconspicuous but can cause some litter under the tree. Winter form of ornamental pear in rock landsxcape with minimal care. In my opinion it has been limbed up too high. I would have liked to see it with more branches lower on the trunk with at least half of its height in canopy. The Ugly. Like most pears, its growth is somewhat upright and tends to get narrow crotch angles which can be improved with proper pruning and limb spreaders. I don’t care for its winter look all that much. Some will disagree with me but the trunk is not all that pretty and its form is just okay in my opinion. It can get iron chlorosis (yellowing of new growth) in some places but can be corrected using iron chelates containing EDDHA. I would recommend it but don’t put it in a small yard and be aware that this is not a low water use plant.

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Joshua Pups Can Be Transplanted

3 Comments / baby agave, desert, Las Vegas, Mohave Desert, Mojave Desert, moving, nevada, relocating, transplanting agave, when /

Q. I have a Joshua tree that is sending out what I’ve been told are “pups”.  In other words, more trees are coming up around the main tree.  Can I transplant the pups to a new area and how do I do that.  Thanks for your help. A.   Pups are produced normally from underground stems or rhizomes.             Not all Joshuas will produce rhizomes that are usually three to ten feet long. If they are closer than this then they could be seedlings and not on rhizomes.            Native Joshuas growing at higher elevations have a greater chance of producing rhizomes than those at lower elevations. I am not sure if this is due to the type of Joshua or the elevation since the research does not say but kind of suggests they are different types of Joshuas.             As you probably know, a Joshua tree stand can be an interconnected web of plants connected by rhizomes or underground stems. Joshuas can also occur from seed. This is not a Joshua but another agave, Agave americana. You can see its “pup” nestled next to the mother plant.             They are difficult to move. Many people believe they must be oriented the same compass direction as they were in the wild to do well.             I would wait about another month before I moved them in early spring. You could take a shovel between the mother plant and the pup and sever the rhizome now. It should not be very deep. Just slice the soil with the shovel as deep as you can in a swath between the two.             Hand water the pup once only. Move the pup around mid-October by taking as much of the soil with it as you can. It does not have to be around the roots of the pup. You just want some of that soil from around the roots to “inoculate” the hole you are putting it into in case there are some beneficial organisms in it.             Make sure the new spot drains easily of water. Water it thoroughly once after you plant it and don’t water it again until next spring and water it deeply again. Water two or three times a year from that point forward. Collecting any Joshua from the wild is illegal and can result in a very stiff penalty.

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What Makes a Good Compost?

Leave a Comment / compost test reports, compost testing, desert, good compost, Las Vegas, Mohave Desert, Mojave Desert, nevada /

Compost quality can be hard to judge. Part of the quality is what you see and what you feel and smell. It should smell good. A good quality compost should smell good. It should not have any off odors. No smell of rotten eggs, no smell of ammonia. Compost should look and smell good. It should look good. It should be dark brown when moist. It should be ALL brown and not some of it brown and some of it not. It should be consistently brown throughout. You should not be able to discern or see any of the products used to make the compost. Leaves and stems should not be discernable. It should be screened so that larger materials have been filtered out. Some composts are screened with multiple screens to include 1/2 inch and smaller particles (1/2 inch minus). Some are screened even smaller than that… 3/8 inch minus or even 1/4 inch. Screening depends on its use. If it is used on let’s say a golf course on greens then large paricles of compost will interfere with the roll of a golf ball when grass is cut at 3/8 or 1/4 inch. It should be cool. Good quality compost has matured to the point where it no longer produces alot of heat. Compost that is still hot has not finished composting and is immature. Part of the compost process is setting it aside to “cure” after the composting process has completed. Compost also has qualities that you cannot see. Pathogens. Generally speaking, commercial composts usually have fewer pathogens that can affect human health than homemade composts. Commercial operations can spend time monitoring and managing a compost pile more effectively than a gardener. Good commercial operations monitor the temperature and moisture contents (and even the oxygen and carbon dioxide levels) so they know when to turn the pile for better aeration, better temperature control and more even processing of the compost. Techniques like in-vessel composting and windrows can generally make a product that has fewer human pathogens in it than static piles that are not monitored carefully. Chemistry. Even though not considered a fertilizer by law, composts contain plant nutrients. They will add “fertilizer” to a garden. They add lots of other things as well. Trace minerals are present along with organic acids that improve soil chemistry. It is always a good idea to ask for compost test results. All commercial compost operations have them. They should provide a copy if you ask them about it. There are potentially some things in compost that we need to take a close look at. Salts. All composts will have salt in them. Fertilizers are salts. Some salts are good and some are not as good. Major salts that can be problems for us in our soils are salts of sodium, chloride, sulfates and boron. Salt levels should not be excessive and the salts that concern us should be minimized. I will give more information on these in future postings. Composts that come from large urban centers can contain heavy metals. In commercial composts the level of heavy metals allowed in commercial composts is highly regulated and monitored. They are not in non commercial composts. Biosolids. Some composts contain biosolids. Biosolids is the preferred name to sludge. This is becoming more and more common as our federal and municipal governments are trying to find an alternative to placing them in landfills. This will become even more common in the future. The use of biosolids is highly regulated in the commercial compost industry with federal limits established by the federal government. I will be discussing this important issue in future postings. In short, you should and must know what is in your compost before applying it to your gardens. Ask for reports on what is in the compost you are purchasing. Make sure that the facility is submitting samples regularly to compost testing facilities.

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Figs Dropping From Tree

Leave a Comment / desert, falling off, fig fruit, green, irrigation, Las Vegas, Mohave Desert, Mojave Desert, mulch, nevada, not mature, small /

Q. We planted a fig tree a couple of years ago. Year before last it produced a couple of figs. Last year there were perhaps a dozen figs which never got larger than a small grape. These did not emerge until November and never grew to full size. The tree was fertilized with 16-16-16 commercial fertilizer, and had plenty of water. Can you tell us why the fruit did not mature and what we might do to have a better result this next season? A. The usual problem is not watering at the right time and keeping the soil moist during production of fruit. We can get two good crops of figs here. The first one is called the Briba crop and is borne on last year’s wood (2013 growth). This is the Briba crop. Notice how the figs are developing on older, brown wood from last year. You can see the new growth pushing from the terminal bud, is green and about two inches long.             The second crop is the Main crop and grows on the current season wood (2014 growth). If the tree is pruned or last years wood is killed by freezing weather, you will only get a main crop. This picture shows you the larger Briba crop still developing at the bottom on older wood. Above these fruit are smaller fruit still developing on this years growth, the main crop. The Briba crop will be harvested while the main crop is still developing.             The main crop occurs when it gets hot and if the tree is not getting enough water the figs will get button sized, get hard and drop off. There is a potential third crop in about September and October but the weather does not stay warm enough in the fall for it to mature.             This third crop will get button sized and will fail to develop due to winter weather coming in. That third crop may form without the summer crop if the tree is not getting enough water. Then in the fall it is getting enough and tries to set fruit but it is too late and fails. Although this is another readers picture, this is what this reader is probably talking about. Late season figs never get to ripen. However, if you keep the soil moist during the summer months, the first two crops will ripen.             I would mulch around the tree with about four inches of wood mulch and cover the soil to a distance of about six feet from the trunk. Water in a basin around the trunk about six feet in diameter.             The basin should be able to hold at least two inches of water but four would be better. Fill the basin with water each time you irrigate. Water once a week now, twice a week in May, three times a week in June, drop it to twice a week in September and once a week mid October.             Once the leaves fall off in winter you can water about every 10 to 14 days. Fertilize once in February with a fruit tree fertilizer or four fertilizer stakes per tree, one in each quadrant of the irrigation basin.

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What To Do to Fruit Trees Now

2 Comments / desert, how much to water fruit trees, Las Vegas, Mohave Desert, Mojave Desert, nevada, when to fertilize, when to prune /

Q. What should we be doing to our fruit trees right now? A. You should be finishing your winter pruning now. Bloom on some fruit trees started early this year and if you haven’t finished it you can still go ahead while it is in bloom. Be careful of the bees.             Hold off on pruning grapes until later in February when the chance of freezing temperatures has passed.             Fertilize your fruit trees now if you haven’t. Use a balanced fruit tree fertilizer high in phosphorus. If you miss this application you can use three or four liquid applications to the leaves (spray) a week apart in the coming weeks.             If you suspect you will have yellowing due to an iron deficiency, apply the iron chelate EDDHA to the base of the tree with your irrigation water. Trees susceptible to iron problems include peach, nectarine, plums, apricots, almonds, apples and pears.             Before or immediately after bloom, but not during bloom, apply dormant oil to limbs and trunk making sure you spray the undersides of the leaves, not just the tops.             Irrigations should be once a week as soon as you see new growth. Newly planted trees can receive 5 to 10 gallons. Trees that are up to ten years old should receive 20 to 30 gallons each time you irrigate. Irrigations should be applied to at least half of the area under the canopy.             Prepare for thinning fruit trees of excess fruit in about a month. Summer pruning will occur in about April. Watch for my postings on future activities and when to do them.

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