Xtremehorticulture

Xtremehorticulture of the Desert

Correction of Cycad (Sago Palm) of Yellow Fronds

Leave a Comment / iron chelate, yellow fronds, yellow leaves /

Q. My sago palms (actually cycads) planted in my yard are turning yellow. Can you tell from this picture what they need? Yellow fronds of sago palm can arise because of its planted location, poor soil used for planting, and watering. A. You have three choices about why the fronds are yellowing: their location (landscape exposure), needed soil amendments (including fertilizers), and improper watering. It is up to you to figure which one (or several at the same time) might be responsible.             Judging from the pushing of new growth from the plants center, I think they are getting enough water during the week. Water this plant three times a week, not more often than that. Don’t reduce the weekly amount of water it is getting! Notice the artificial grass that was installed. Removal of a lawn and replacing it with nothing that adds to the soil can cause yellowing of fronds due to a slow decline of organic matter in the soil.             When you are watering, apply it to a depth of 12 to 18 inches. This will mean that you need to apply in a single application anywhere from 5 to 8 gallons of water. Apply this water through three emitters, located 12 inches from its trunk, to get a good distribution of water. Don’t split the application of water in the morning and another in the afternoon. That’s silly unless you see an enormous puddle of water when you irrigate. If water puddles on the soil surface, split the application of water into two applications an hour or less apart. Rooting depth and how deep to water varies with the size of the plant. Taller plants need deeper (and less frequent) watering.             This plant is originally from the richer soils of northern India. It evolved with these types of soils. It doesn’t like the extremely low organics of desert soils! Iron fertilizers should be added to the soil in the early spring but now is okay to do it. Be sure to add this composted soil where the soil gets wet. If the compost you are adding comes in a bag without a description, then it is probably low in fertilizers as well. Mix in the appropriate fertilizers to the compost before mixing it with the soil. Late in the growing season requires spraying iron on the foliage several times about a week apart to be effective.             Make sure any surface mulch is at least two inches deep. Using mulch adds one or two days of extra water! Mulch can be crushed rock or wood chips. Wood chips are better because they decompose in wet soil adding organics to it as the wood chips decompose. Crushed rock doesn’t add any organics back to the soil. You should add organics to the soil (compost) every two years if the mulch is crushed rock. Rock surface mulch adds minerals to the soil as it breaks down, not organics.  Plants have to handle that.             If a lawn was removed in the past three to five years this might explain the yellowing as lawn adds “organics” back to the soil. Removing the lawn also removes the “organics” added by lawns. Lawns add organics back to the soil from its root growth and lawn clippings left to decompose.             I don’t think this cycad will be better in a different location’ but cycads grow best on the north and east sides of a home. They prefer to grow with morning sun and afternoon shade.

Correction of Cycad (Sago Palm) of Yellow Fronds Read More »

Privet Thin Canopy and What to Do

Leave a Comment / ligustrum, privet, thin canopy, yellow leaves /

Q. What is wrong with this bush or tree? What can I do to make it look healthy? Not the tree reader is talking about but it does have a “thin” canopy. It is not dense. How to thicken it? More water and applied to a wider area and add fertilizer once a year. If it is yellow like this, add chelated iron (I prefer iron EDDHA) to the fertilizer in very early spring. It may need compost added to the soil top as well. A. What I am seeing is a thin canopy and some leaves that have brown tips (leaf scorch). I think this is a ligustrum or privet. When I see a thin canopy, it usually means the soil has “run out’ of organics. Rake the rock on top of the soil back about two feet in all directions and apply a thin layer of compost. This compost will “dissolve” into the soil with water and increase the “organics”. Japanese privet in particular has a difficult time holding leaves when grass is removed. Leaf scorch or tip burn revealing the plant is not getting enough water, it is planted in a place that is too hot, or plant nutrition is bad. Increase the water to the plant, consider moving it to a new spot, or improve its nutrition with fertilizers or compost or both.             This time of year (beginning of October) we are transitioning from watering three times a week to two times a week. Each application should be about 5 to ten gallons of water applied to this area via three to four emitters. This can be calculated with the number of minutes you are applying water combined with the size and number of drip emitters. To change the amount of water, do not alter the minutes but instead increase the size of the emitters, or increase number of drip emitters.             The other option is to replace the surface rock with a layer of fine woodchips over this same area. For faster results apply a thin layer of compost to the soil surface and water it in. Then cover this area with woodchips.

Privet Thin Canopy and What to Do Read More »

Leaves Yellowing on Calamondin Citrus Tree

1 Comment / calamansi, citrus, yellow leaves /

Q. What causes leaves to yellow and black spots to develop on leaves of my calamondin citrus tree? I had them for seven years and they just now developed these yellow leaves with black spots. Nursery information desk advised picking off all affected leaves (but there are too, too many) then spray with cooper fungicide. A. Combined with leaf yellowing, it sounds like either a nutrient or watering problem or both, not a disease problem. Copper sprays like Bordeaux Sprays, are usually recommended for disease control but I don’t think that is it. This is photinia but you get the leaf yellow idea from this pisture. Try this:     1. Cover the soil with 1/4 inch of rich compost or compost plus some fertilizer high in nitrogen     2. Then cover the compost or compost/fertilizer with woodchips     3. Apply a citrus fertilizer in January     4. Try adding an iron fertilizer (I suggest an iron chelate called 133 or iron EDDHA) This is the most effective iron treatment (EDDHA chelate) but it is more expensive than other iron chelates. Apply it in the spring (February) or no later than early summer (April/May) for best results. If these citrus trees are in rock mulch, then it’s a nutrient and drainage problem. Auger four or five holes into the ground, 2 feet deep and 1 to 2 feet from the trunk, to improve drainage. Fill these holes with soil mixed 50/50 with compost and an iron fertilizer. Citrus fertilizers contain plant nutrients in higher concentrations than other plant nutrients particularly when these fertilizers are formulated for the desert Southwest like Arizona’s Best and Grow Well brands.              Mix iron chelate with the compost before using it to fill the augured holes. Water once a week through the augured holes, filling them with a hose. Also, try spraying the leaves with an iron chelate solution four or five times, a few days apart. If this is an iron problem, even though it’s caused by poor drainage, the leaves should begin to get darker in color. Put about four of these holes about 18 to 24 inches from the tree trunk  and 2 to 3 feet deep to improve drainage. If they are filled with gravel or woodchips they will stay open. They act as drainage sumps (French drains) around trees (vertical mulching). Nutrient problems can be caused by poor drainage. That’s why I’m giving a recommendation to improve the drainage using vertically augured holes and combining it with a compost and iron application at the same time.

Leaves Yellowing on Calamondin Citrus Tree Read More »

Multiple Reasons for Spring Yellow Leaves

Leave a Comment / asian pear, fruit trees, yellow leaves /

Q. My Asian pears look sickly again this year with yellow leaves. Last year after their planted the new growth was yellow and again it’s happening this year. New growth on Asian pear is light colored or yellow. This can be for many reasons. A. There are several possibilities why plants have yellow leaves when they’re young. Some plants have light colored leaves when they are young and get darker as they get older. If this is the case, don’t worry about it.  Chojiro Asian pear growing in the Las Vegas Valley in the Eastern Mojave Desert. Planted too deep The first is rather simple. Their planted too deep. Fruit trees must be planted the same depth they were when growing in the nursery. Those fruit trees that are grafted or budded must have the dogleg above ground.             If the hole is dug too deeply and the soil is amended, it’s possible the tree will sink deeper after it’s planted and soil will fall around its trunk. Wet soil around the trunk can rot it. This is the reason it is best not to dig the hole deeper than is needed for the roots unless there is a drainage problem. This pomegranate was planted in a depression in a lawn. Are the roots staying too wet? No way to know until you check the soil  and see how wet it is just before the next irrigation. Soil doesnt drain water  The first sign there is wet soil around the trunk and it’s starting to rot are yellow leaves. If not corrected, it can kill the tree. If the bud union is below the soil, water can rot the union and it will die. In milder climates the top part of the tree can grow roots and you will lose the benefit of the rootstock. This is an apple tree growing in an orchard in the mountains of Lebanon on terraces. The soil was kept too wet near the trunk the tree developed collar rot. Borers Another reason for yellow leaves are borers. You would think that trees coming from a nursery wouldn’t have insect problems but they do. After supervising the planting of hundreds of fruit trees, I would estimate there are borers in two out of every 100. Trees most susceptible include peach, nectarine and apple. Others are also susceptible but less so in my experience. Borers in ornamental plum             Water drainage through the soil can also be a problem. If watering too often and the roots stay wet, they will begin to rot. Rotting roots decrease the plants health and this shows up as yellow leaves in the top. Check the soil moisture and make sure the soil is not watered daily. Soil improvement             Sometimes the soil is not improved enough at the time of planting. I like to see about 50% of the volume of the soil used for planting amended with compost if this is desert soil. Less compost is needed in other soils but it’s still a good idea.             Compost improves water drainage through the soil but it also helps the soil hold water. I know it sounds crazy but the soil structure where air is contained is improved while also the channels for draining water are improved at the same time. It is either drainage/water problem, planted too deep, borers or lack of fertilizer. If this lack of color continues, spray the leaves with a liquid fertilizer spray.  Mixing a liquid fertilizer and spraying the leaves. Use either a Fertilome, Grow More or even Miracle Grow product with high nitrogen. A lawn-type fertilizer would be good for young trees. You will need: Distilled water (tap water in Las Vegas is pretty bad quality) Water soluble fertilizer Use liquid spreader (baby soap or Castile soap liquid or  EZ wet from Viragrow) to help fertilizer get inside the leaves and. Add what it recommends on the label or ½ tbs per gallon. Steps Add water to the sprayer so it is half full Add water soluble fertilizer at rate on label. Finish adding water to the spray so that it mixes all well. Add spreader (EZ Wet) to the mix and stir. Spray leaves to runoff, top and bottom. You should see a change in leaf color in 48 hrs

Multiple Reasons for Spring Yellow Leaves Read More »

Star Jasmine Problems Mostly Soil, Mulch and Cold Related

14 Comments / bronzing of leaves, Las Vegas, leaf drop, Mohave Desert, Mojave Desert, nevada, scorching leaves, yellow leaves /

Q. What can I do to correct all the issues afflicting the star jasmine this winter? Problems with star jasmine. Most of these are caused by poor soil conditions and winter cold. Perhaps it might be not watered with enough water. A. The easiest is to not plant it. Hard to say exactly but generally I would call the problems in general, stress. The stress could have come from freezing temperatures, lack of water, poor soil or poor soil amendments such as high salts and lack of organic matter. Great place to put a star jasmine for aroma and welcome greetings to visitors.             The plant is some eastern and southern China and which means it is not from a desert and not really a desert plant. We have to adjust everything around it for that reason. It is not going to like desert soils or rock mulch for that reason. Star jasmine used as groundcover in rock mulch. I guarantee that plant HATES it there. Developed iron chlorosis due to rock mulch and poor soils.             Soils must have lots of rich soil amendment (compost) and it will really appreciate wood mulches. It does well as a groundcover but I think it is best as a north or east-facing trellised vine. Particularly near a window that can be opened in the Spring. When star jasmine is growing well and in good health the leaves should be a vibrant green.             The flowers are very fragrant so it should be planted in locations where the fragrance can be appreciated. It is an old-fashioned plant. Southerners might know it by the name “Confederate jasmine”.             It handles the cold winters well if it is not in rock mulch. At real low temperatures the leaves may get that bronzy, yellowish color that plant leaves can get when it is cold but will handle temperatures to 10F pretty easily. Citrus leaves will bronze in winter the same way.             Flood the soil with water to remove possible salts and let it drain. Add compost to the soil surface around it and water it in. Replace rock mulch with wood mulch but keep the mulch away from the stems to prevent collar rot.             Fertilize in the spring with a good quality fertilizer for flowering plants like roses. Shear off the old growth and let it regrow in good health. One time I had to cut a star jasmine used as a vine way back to get it to flower for me in a north exposure.

Star Jasmine Problems Mostly Soil, Mulch and Cold Related Read More »

Is My Photinia Over or Under Watered?

Leave a Comment / red spots on photinia, scorching, yellow leaves /

Q. I have no idea if I am over watering or under watering. My red tip photina plants are all brown and dropping leaves left and right. My sago is turning yellow. I have a drip system and it is set for twice a day ever other day for 10 minutes. Is that enough? Photinia growing in rock mulch A. Usually drip irrigation is measured in gallons per hour, not in the number of minutes it was operating. Each emitter operates in a specific number of gallons, or fraction of a gallon or liters, it will deliver in one hour.  Problem photinia Drip irrigation does not need to come on twice a day unless the drip emitters are those emitters I don’t like very much, the kind you can twist open and get some unknown volume of water. Under the right conditions those will put out so much water that it can run all over the place. Then you might need to have it come on several times just to keep the water in one spot. With drip irrigation you should apply all of the water it requires in one application.  If your drip irrigation is operating at the same time as your lawn is being watered then this is a big no- no. This is frequently why drip is operating in that ten to fifteen minute range. Lawns should be irrigated separately from trees and shrubs.  In your case, If your drip system is applying 2 gallons per hour through the emitters then the plant is getting 1/3 gallon each time you water which is 2/3 gallon total every other day.  The larger the plant, the more water should be applied to it.  For a one foot tall plant try and give it about 1 gallon of water each time you irrigate.  If your plant is 2 feet tall then try giving it to a gallons of water each time you irrigate.  If plants are 5 feet tall, give them about five gallons of water at each irrigation.  This is a very rough estimate.  My sense is that you may be under irrigating. Photinia after corrective action was taken Photinia have another big a problem if they are growing in rock mulch.  In rock mulch, they tend to yellow and begin to scorch around five years after they have been planted.  The soil under the rock mulch has become mineralized and they can not take up enough nutrients to satisfy their needs.  You can try to supplement these mineral requirements by adding a good fertilizer once or twice a year and an iron chelate to the soil in about late January or February.  Try using a good quality fertilizer for trees and shrubs like miracle grow and add an iron chelate to the soil such as iron EDDHA.  It is hard to find and expensive but usually Plant World Nursery on Charleston boulevard carries it. If a Sago palm is planted in a very hot location with lots of reflected light it can begin to yellow.  It can also begin to yellow if we have a very low winter temperatures.  You will see yellowing due to very cold low temperatures very early in the spring or late winter.  If it is yellowing because of a lack of iron then the iron chelate mentioned above will correct it.  If the yellowing is because of watering too often then you may correct it by correcting your irrigation and not watering twice each day but watering only once on the irrigation day but applying more water.  

Is My Photinia Over or Under Watered? Read More »

Kumquat Yellowing in Landscape Planting

Leave a Comment / iron chlorosis, rock mulch, yellow leaves, yellow plants /

Q. Here is one of two kumquat trees that I am trying to grow. As you can see it is not working.  I feed and water them what is the problem? Can you help?  Or should I discard?   A. The issues on the other picture could be related to a mineral fertilizer problem. This one could be the same but with the leaves gone it is hard to tell. It also might be related to whatever soil amendments you put in the ground when you planted the trees. But I am pretty confident it has to do with the soil, fertilizer issue or irrigation. It does not help much that they are surrounded by rock mulch. Let’s handle one at a time. Make sure the tree was planted in your soil at the same depth it was in the container. If there was some extreme cold weather, it might also be cold weather damage if you did not see this before it got real cold. Irrigation. Irrigations should be generous but not frequent. A tree that small can get by with ten gallons of water at each application. If these are on drip emitters you should have enough emitters or run the minutes long enough to deliver ten gallons at this size in its life. This time of the year once a week is often enough. When you start to see new growth, bump it up to twice a week with the same volume of water each time. Fertilizer. Go down to Plant World Nursery on Charleston (they are the only nursery I know of in town that carries this) and buy a one pound container of iron chelate fertilizer. If you ask for Doug, Brian or any of the main staff they will direct you to the right one since I recommend it a lot. They even have my name on the label now so people will believe them when they direct them to this product.   For each tree mix about two or three tbs in a one gallon container, stir it and distribute it around the base of the tree where the drip emitters are. Water it in with another gallon since it is sensitive to light. Get some rose fertilizer (like Miracle Gro type) and use it on the kumquat or get some fruit tree fertilizer stakes and put the fertilizer under the rocks or drive two stakes close to the emitters. I think the Miracle Gro is better. Fertilizers are salts. Keep all fertilizers at least 12 inches from the trunk when applied. Mulch. If this were me, I would pull the rock mulch back a couple of feet and put down some good compost (don’t buy cheap stuff) and lightly dig it around the trees from the trunk to a distance of about two feet from the trunk. I would cover the area around the tree in wood mulch but not bark. Keep wood mulch six inches away from the trunk so that it does not cause the trunk to rot if it gets wet. Older trees it doesn’t matter. Lets see if this works for you.

Kumquat Yellowing in Landscape Planting Read More »

Fertilizer Formula for Keeping Crepe Myrtle Healthy in Desert Landscape

Leave a Comment / crape myrtle, crepe myrtle, desert landscape, scorched leaves, yellow leaves /

Q. We have a crape myrtle tree in our southwest back yard. It gets plenty of water and I fertilized it last month with some Miracle Grow flowering fertilizer. At the time there were some burned edges on some of the leaves and some yellowing. Now it is really burned on the edges of all of the leaves with yellowing. HELP! Crape myrtle growing at Center for Urban Horticulture for 20 Years on Formula Mentioned Here A. A couple of things on your crape myrtle. I have kept crape myrtle growing in raw desert soil in good shape for 20 years at the Center for Urban Horticulture and Water Conservation in North Las Vegas. I used a combination of a general purpose tree and shrub fertilizer (16-16-16) plus an iron application combined with foliar sprays of Miracle Gro.             I don’t really endorse products but Miracle Gro is the one I used and have found to work just fine. You could just as easily use a different good quality foliar fertilizer for flowering woody plants. I apply the granular 16-16-16 in late January or early February using about 2 lbs. of fertilizer applied to the surface of the soil and watered into the roots without it washing against the trunk.             You can make some shallow holes in multiple places under the canopy and water it in thoroughly. At the same time, I also apply an iron chelate, iron EDDHA at the rate of a tablespoon or two scattered in the same holes and watered in so that none of it remains on the soil surface. It is light sensitive.             After about one month of new growth I then foliar fertilize the tree with a Miracle Gro spray or comparable product. I do both of these annually. You can do the same thing (except for the iron) by using a fairly large quantity of good quality compost annually. My guess is you either are missing the iron application, watering too often or not watering deeply when you do water.

Fertilizer Formula for Keeping Crepe Myrtle Healthy in Desert Landscape Read More »