Q. What are your thoughts on mychorizae?  I bought some a while back from T&J Enterprises out of Washington state, and the chiles seemed to do really well.  Is it an aid or just my imagination? A. I have had some experience with mycrorrhizae in the past and if the soil is void of these critters then plants will definitely improve if some is added. But if the soil already contains the right kind of mycrorrhizae then it won’t do much. Mycorrhizae should not cost so much and they go a long way in your soil since they multiply under good growing conditions. These are fungi that live in and around plant roots. In the past they were normally associated with better uptake of phosphorus but now they have had many other things attributed to them as well. I always like to take a little bit of soil from where a plant was growing just for the mycorrhiza content. That little bit of soil will have enough mycrorrhizae to inoculate your soil.

Q. We have a Black Mission fig tree with about one hundred well-formed but still very green fruit. This will be the second crop for 2012. It is now the first week of November. We are afraid that the frost will come before these fruit mature. Do you have any suggestions on maximizing our yield from these trees? This is becoming an annual problem. Two different crops of figs on the same branch: early figs (briba) on the older, darker wood and the second crop (main crop) on the green new growth.   A. In our Las Vegas Valley climate it is very common to have two crops of figs each year. In fact, if we could maintain warm temperatures through November we would actually get a third crop of figs.             The first crop of figs in the summer comes from growth or wood that grew the previous year. In other words, the first crop of figs you should be getting the summer of 2013 will come from wood that grew in 2012. It is easy to see the difference between wood produced in 2012 from older wood because of the color difference.             The second crop of figs, as well as the late third crop which you are seeing now, comes from the current season wood. So this coming year the second and third crop will grow on wood produced in 2013.             There are the two things that you will most likely have to do this coming winter and the subsequent growing season. When you prune your fig tree this winter, leave some wood on the tree that grew this past season. Fig along fence after winter pruning at The Orchard             If you want an early crop, the first crop, you must leave some of last year’s wood on the tree. If you remove this wood by cutting everything back you will remove the early crop of figs. If this wood is excessively long, you can cut some of it back and it will still produce fruit. I would leave 2 to 3 feet of this wood remaining.             If this wood, last year’s wood, is not very long it means your tree is not getting enough water. Normally the wood produced last year could range from 2 to 6 feet or more in length. It varies with how much light it is getting, position on the tree, if it is upright or not, etc.             Two things that will give you more growth is water and surface mulch. Fig trees do very well with organic surface mulch or wood mulch on the surface of the soil. 3 to 4 inches or more would be great.             You would water a fig tree just like any other landscape tree that is not a desert plant. Figs are not really desert adapted. They are typical of more Mediterranean climates and they do like water for the production. I hope this helps. Watch my blog for this question and I will post pictures.

Poplar or cottonwood growing in desert landscape. It is difficult to water these types of trees in our climate due to their high water demand and our irrigation systems not intended for very large, high water-demand trees. Bob, I have 2 cottonwood trees that are about 15yrs old. They were doing very well until about 2 years ago. At that time I noticed a limb here and there dying. Now more and more are dying off. I cut off a limb that broke in the wind recently that was partially dead at the top. I saw bugs in the area that was dying. The bark turns brown and peels off the limbs that are dying. Also when I cut off limbs that are dead or dying the wood under the bark is turning a dark brown at the center. I found info on the internet that recommended using a pesticide applied to the soil along with a 10-10-10 fertilizer mix. I just did this last week so I don’t know if this will help. What do you recommend? What do you think is the problem? Am I doing the right thing? What do you suggest? I really appreciate your help. It would be a shame to lose these beautiful trees. Jim Jim Cottonwood trees require lots and lots of water. I hope these are not growing in a rock or desert landscape or you will have problems. If you will be successful they should be growing in a large turfgrass area with you supplying supplemental water to them deeply twice a month. This means not only are they receiving water from the lawn, but you would be watering them with extra water down to a depth of 18 to 24 inches twice a month during the growing season. The area that you are watering under the tree should be approximately the same area that is under the canopy or spread of the tree. It is hard to judge but my guess would be that you are getting branch dieback from a lack of total water applied to the tree. These trees will not survive for any length of time if they are in drip irrigation. I would highly recommend that these trees be watered with a bubbler that releases large amounts of water quickly into a basin beneath the tree. This basin should be the size I mentioned above. I don’t believe that there is anything wrong with this tree that lots of water applied under the canopy would not cure. Watering schedule during the summer months would be every 2 to 3 days. The frequency of applied water decreases in the cooler months but the volume of water applied remains the same… that water needs to travel in the soil to a depth of 18 to 24 inches beneath the tree.

Dear Bob I purchased this nectarine at the orchard in either Jan/Feb of this year.  Since I planted it on a slope, I cut the trunk to 30″ versus the 24″ recommended by the gardener.  Unfortunately, as you can see from the picture, it only put out one scaffold branch? I know you get hundreds of pruning questions, I read all of them on your blog, but I was wondering if, since it is still a young tree, if I should lower it another 6″ in the hope that it will put out  more than one scaffold branch.  Or, if I should just live with the existing scaffold and hope that others will develop? Any suggestions you could offer would be greatly appreciated. Sincerely, Scotty. Sotty That also happened to me on a peach once. These things do happen. When we make these dramatic cuts we sometimes don’t get pretty results. Peaches and nectarines both sometimes, depending on the variety and the size of the trunk, may respond by making one new shoot or several. However, the larger the trunk on peach or nectarine we cut the more chances we will have of getting fewer new shoots. Smaller trunks will give you more shoot development… typically. There are three things you could do. This might depend on what you want the tree to look like. For production purposes you are fine where you are…. A bit higher than I would have liked to see but you will get fruit. But it does look a bit odd when it is young. This will disappear over time and you can enjoy the fruit soon. You can recut the trunk (gulp). This is risky but what the heck. You will learn something one way or another. It might again send up one shoot. It might send up more than one shoot. It might not send up any new shoots. I can’t tell you what is going to happen but if I truly did not like the look of it I would recut the trunk and take a chance. If I don’t care about the looks so much then I would let it go. Next time, pick a younger tree with smaller diameter trunk and cut it at knee height to start your scaffold branches. In one season you will not have any difference in size between the two.

Hi Bob:  I understand you are in Afghanistan.  Stay Safe over there!  If you have time to address my rather insignificant problem compared to where you are right now I would appreciate it.    If not …no sweat! I have a large 12-15 year old Keiffer Pear Tree that always has literally hundreds of large pears on it each year.              I am just harvesting them and this year the pears look fantastic and are especially large but when one cuts them open all of them have rotten areas within the pear.   Perfect on the outside but ruined on the inside.   Last year they were perfect both inside and out…no problems but not so this year. I am sending a picture…hope you get this.   Any clue as to what’s going on with these pears?               The only issue I had with the tree early In the summer was a severe iron deficiency that I treated with an iron solution.  Don’t know if this caused the pear problem or not. I would appreciate any info you can give me.  Billy Keiffer pear at The Orchard Billy. This is a tough one but I do not believe your applications of iron had anything to do with it. From the picture I believe this is called brown core or pithy brown core. I could be wrong. But the brown area would be pithy, not wet or watery. If this is in fact what it is I do not have good news because no one seems to know what causes it. Let’s run down a list of possibilities. One suggestion is cool weather. Some suspect that unusually cool weather can cause this problem in fruit. Another suggests that if you leave the fruit on the tree too long the fruit can develop this problem. Another suggests if you harvest the fruit and do not cool it down soon after harvesting this problem can develop. Whatever caused it, from your description, it happened to all of the fruit this year. Look and see if the fruit on the South and West sides are harder hit than the ones on the North or North East side. Let’s rule out over heating of the fruit. If you don’t have good leaf cover on the tree this might be a problem because the fruit may not get enough for shade and cooling. Corky spot on Comice pear at The Orchard When harvesting the fruit, try harvesting the fruit a little earlier, maybe mid-October, and let them ripen a little bit off of the tree but inside the house. Make sure when they are harvested they do not sit in the sun for any length of time. There is another disorder called corky spot that cause the flesh to be brown and pithy just under the skin. This is due to a calcium deficiency and calcium sprays are recommended five times during the growing season to alleviate this problem. But this does not appear to be corky spot. That’s about all I have to offer. If it does not happen again next year and you have not done much different perhaps we can conclude it was due to weather.

 Granular sulfur remaining on the surface of a desert soil three years after its application. Arid soils and irrigation water in the desert southwest present numerous problems to nondesert plants that are brought in from other parts of the country and the world. These problems include high pH and high levels of sodium and bicarbonates. Sulfur, in one of its many forms, is commonly used to reclaim these soils and water and improve their quality so that a broader range of plants may be used in landscapes. Sulfur, in the form of sulfuric acid, is used for injection into irrigation water to combat pH and high bicarbonates.   In some parts of the country granulated or micronized sulfur is used as part of the fertilizer program when it has been found to be deficient through soil or tissue samples or when a lowering of soil pH is needed. The purpose of using sulfur in a maintenance plan, and which form to use, is often confusing to a landscape manager. This can lead to disappointment when the results from the use of sulfur containing materials don’t live up to the expectations of the landscape manager. In horticulture and agriculture, sulfur is used for two primary purposes: as a nutrient for plants growing in sulfur poor soils and to reclaim poor quality soils and irrigation waters. It should be noted here that all sulfurs and sulfur products are not the same. The form of sulfur that would be picked as a fertilizer is not necessarily the same form that would be picked for reclaiming poor quality soil and water. Sulfur is an essential plant nutrient. Fortunately it is plentiful in most soils and shortages are not common but they do occur. Plants take up sulfur from the soil in the form of sulfates. Fertilizers that contain sulfur usually contain it in the form of elemental sulfur (soil sulfur) or in the sulfate form such as ammonium sulfate. Sulfur is converted to sulfates through a process called oxidation. When applied to aerated, moist soils, elemental sulfur is oxidized by soil microorganisms to form sulfuric acid. This sulfuric acid in turn supplies the sulfate ion that is taken up by the plants. During this conversion from elemental sulfur to sulfates is when sulfur releases its acidifying power. When elemental sulfur is incorporated into soils the oxidation of sulfur to sulfates is what helps to temporarily lower soil pH. Sulfur containing fertilizers should be applied to soils when sulfur deficiency has been clearly established through soil tests or tissue analysis. The preferred sulfate fertilizer is ammonium sulfate due to its price, solubility in water and availability. Since the sulfur contained in sulfates has already been oxidized, the acidifying power possessed by sulfur has already been lost. The sulfates contained in fertilizers have little affect on the pH of a soil or water when added to it and so may not be a good choice if lowering the soil pH is desired. Elemental sulfur, sometimes called soil sulfur, is not a good choice to quickly correct a sulfur deficiency or quickly lower soil pH. To become available to plants and release its acidifying power it must be first converted to the sulfate form by microorganisms. Like all microorganisms they are most active and efficient under environmental conditions that promote their activity. The size of the sulfur particles, soil temperatures, moisture and oxygen levels must be in a range favoring their growth and activity. Peak oxidation levels, provided soils are well aerated, occur at soil temperatures of about 85 degrees F. This conversion from sulfur to sulfates in soil is a relatively slow process even under the best of conditions. Even though acidification around the sulfur particle may be relatively quick, the diffusion of sulfuric acid to the surrounding soil volume is generally slow. Generally speaking, given warm soil temperatures and good soil aeration, the smaller the sulfur particles the faster the release of acid and the formation of sulfates. This is why elemental sulfur is sometimes combined with bentonite clay to help in the physical breakdown of the sulfur particle. In water, a bentonite-sulfur particle swells, breaking it up into very fine particles. Once broken into small particles, the increased surface area allows soil bacteria to transform the sulfur to sulfate more quickly. However, even in the presence of small particles, transformation of sulfur to sulfate is a slow process often taking months. Elemental sulfur may be a good choice on a long-term management program provided the economics justify its use. Reasons for continued application to soils include the temporary, but long term lowering of soil pH and the reclamation of soils containing excess sodium. Elemental sulfur is often chosen to lower soil pH, but it must be used carefully since it can have a high potential to burn plant tissue under certain conditions. The amount of sulfur needed to decrease soil pH is determined from a soil test by the amount of lime contained in the soil. Each 10 pounds of elemental sulfur generates enough acidity to neutralize 30 pounds of lime. Applications are best made when temperatures are warm enough for the bacteria to oxidize the sulfur but not hot enough to burn leaf tissue. Since sulfur does not generally move in soil, surface applications may be tied up in the thatch layer and not move into plant root zones. Generally temperatures above 90 degrees F would be the upper limit for applications. Incorporation of sulfur into the soil just after coring is a good method for reducing burn, reducing contact with plant foliage, improving aeration and moisture conditions for the oxidation of sulfur and treating a greater volume of soil than just applying it to the surface. Published rates of application for turfgrass are less than 5 pounds of actual sulfur per thousand square feet for bermuda and less than 0.5 pounds for bentgrass per application. Reapplication would depend on soil pH tests. Sulfur is also used for reclaiming sodic soils

  Autumn Maple in rock landscape. Bad idea. Q. We have a young Maple tree in our yard that we planted last October. We may have messed up when we planted it to replace a shrub that was dead when we moved in. The tree is in full sun all day. Last year toward the end of summer it lost most of it’s leaves – they looked burned. However it re-leafed itself before going dormant, and survived the winter. So we figured it was because it was a young tree and might be okay this year.  Again this year it has done the same thing and is at present in it’s second bloom of leaves.              My question is, would it be better to move this young tree to a part of the yard that is not in full sun all day, and if so am I right in believing it would be better to wait until it goes dormant for the winter before doing so? Any advice will be much appreciated. A. Oh boy Bill. This is not going to be an easy tree to take care of. Maples is a huge category of trees. They range from the ornamental and shade trees common to the northern and eastern states to the highly ornamental Japanese maples and even our native maples. But unfortunately all of them will struggle.  Autumn Blaze maple in desert landscape in Summerlin Nevada             I have seen two instances of Japanese maples successfully grown in Las Vegas. They were in sheltered, shady parts of the landscape. The soil was highly modified with compost and other sources of organic matter. In one case many years ago it was growing in a lawn situation. The other was in a shrub border with lots of organic mulch. Another possible Maple you could play with are native maples such as Bigtooth Maple. If this is a Red Maple, Sugar Maple Or Silver Maple you will have some big problems down the road if you can get it to grow. I like to encourage people to try new things but if these are maples used for shade trees I would get a replacement and check it off as part of your education. I have one entry in my blog concerning maples that you might find interesting concerning Autumn Blaze Maple in Las Vegas. http://xtremehorticulture.blogspot.com/2011/10/autumn-blaze-maple-not-good-choice-for.html Yes, you should move it now so it has the remainder of the fault to reestablish the root system and a spring for more growth before it gets hot. Pick the North side or shadiest part of the yard. Dig the hole 3 feet wide. Amend this volume of soil with about 75% compost. Plant it at the same depth. Stake it solidly in the soil so the root system cannot move. It is okay for the top to move but the roots should be totally immobilized. Cover the surface of the soil with 4 to 6 inches of wood mulch, keeping the mulch away from the trunk 6 to 12 inches. The mulch should totally cover the surface of the soil and the hole that was dug. I hope this helps. Try to find out or remember the type of Maple it is. This makes a huge difference.