"Fluffy" Soil a Problem When Reseeding a Lawn?

Q. Preparing to reseed a few bad spots in my lawn. I was surprised to find the ground completely infested with a spidery web of roots. The soil itself seems to have been changed to a fluffy, powdery texture. I’m thinking I should remove and replace the soil before seeding these spots but am concerned these crazy roots will grow back. Any ideas as to what they are and what I should do about them?

When Bermudagrass has a chance to grow rampant it can produce a thick mat of roots, similar to a spiderweb, that can cause the soil to be "fluffy" or "puffy".

A. I am guessing this "fluffy soil" you're talking about may be the Bermudagrass rhizomes mixed with soil. That's what your picture looks like. To repair it requires removing all these rhizomes all the way down to solid bare soil. Once you have done that, the soil should be about at the right height for seeding. I don't think the soil will be lower than it needs to be. Since you are right next to a sidewalk, the soil should not be more than about 3/8 inch lower than the sidewalk. If it's lower than this, you can add some soil to the area but I kind of doubt you will need to.

What bothers me, and I'm right it is Bermudagrass, is why it's there in the first place. Bermudagrass invades spots in the lawn that are drier than other areas. It out competes fescue where its dry. Sidewalks and driveways are hotter than other areas, so the lawn uses more water in these areas. Adjust your lawn sprinklers so this area gets more water.  You may have to water the entire lawn more often or with more water just to compensate for this dry area unless you fix the irrigation problem.

Bermudagrass thrives where it's hot and dry. It will outcompete fescue in a lawn where it's dry. Putting one sprinkler to cover an area that's triangular-shaped will cause Bermuda grass to invade that dry area.

Bermudagrass is even more aggressive if the lawn is mown short. Make sure the lawn is mown as high as possible during the months of April through October when Bermudagrass is most aggressive and no bevel cuts when you edge the lawn!

When to Use Woodchips and When to Use Rock?

The relationship between amending the soil at planting time, the choice of using woodchips as a surface mulch, or applying crushed rock instead, also relates to the types of plants found in your landscape. Of course, I like compost best to amend the soil at planting time, but other amendments will also work. Adding amendments to the soil does two things: it makes the soil “fluffy” (changes the soil structure by making the soil more porous) and adds whatever plant nutrients to the soil that it contains.

Chinese photinia is from where??? You guessed it, China. Plants not coming from the desert Southwest should be planted in wood chips and soil amended with compost.

What are rich composts?

Some composts are rich and full of nutrients, i.e., made from sources of manure. Other times they are not so rich, and the addition of a fertilizer might be needed. Some of the chemicals in the compost are “tied up” inside the compost and released slowly as it “rots” in the soil. Others are quickly washed into the soil with the first few applications of water. Some of these chemical additions can be good and some are not. It depends on what was used to make the compost. The only real way of knowing its chemistry is testing the soil through a certified laboratory or trusting the compost supplier.

This is an example of a "rich" compost, Viragrow's 166. It is full of plant nutrients, about $150 worth of plant nutrients in every cubic yard, but also contains biosolids. It's a tradeoff. Do you want to recycle your poop? You made it.

 

Planting amendments mixed with soil

Planting amendments like compost mixed with the soil at planting time, and then covering the soil with rock mulch, gives many plants somewhere between three and five years before the plant has problems (it doesn’t add the right kind of plant nutrients when it decomposes). By that time the soil amendment(s) used at planting time are gone. Plants sensitive to the loss of amendments respond by the leaves first turning yellow and scorching, followed by leaf drop, and finally followed by branch dieback.

This is also a compost from Viragrow. It is plant based and "organic"; it does not contain one iota of biosolids. But it is lighter in color, more coarse in texture and not as "rich" in plant nutrients. A fertilizer should be applied to the plants along with this compost.

Sometimes this process weakens the plants enough for insects like borers to finish the job. This is particularly true of plants like Photinia, Nandina/heavenly bamboo, Sago Palm, Japanese blueberry, Carolina Cherry Laurel, and most fruit trees.

Applying compost to rock landscapes.

There is a trick you can use if your landscape is already covered by rock. Rake back the rock to bare soil three feet away from these plants and apply a rich compost (or compost plus fertilizer) to the soil surface (even better if you lightly “scratch it” into the soil), water it in, and put everything back including the rock and irrigation. If the landscape area has rocks bigger than one inch, the rich compost can be applied on top of the rock and wash it in without raking the rock! It’s easier that way. If you have had yellow plants in the past, count on using this method every three years. You might consider adding your favorite iron to this application if it’s applied in the spring and these are iron critical plants.

General Rule of Thumb

When planting with plants from the desert Southwest, they can tolerate rock. When planting with plants not from the desert Southwest, use wood chips.

Mexican and California Palms are Not That Easy to Tell Apart. Or Are They?

Q. My husband and I are snowbirds from Canada. We try to have our yards as low maintenance as possible. The Mexican fan palms in our backyard are bulging up, pushed and broke the bricks on the ground again. How often are these pruned? Will they get much bigger?

Mexican fan palm, Washingtonia robusta, is known for its height and the narrow trunk. California fan palm, Washingtonia filifera or desert palm (palm on the bottom), is known for its broad trunk and shorter stature.

A. Two most common palms considered for home landscapes are the Mexican and California fan palms. The difference between the two is that Mexican fan palm has a narrow trunk while the California fan palm has a very wide trunk. These palms interbreed with each other so it's very difficult to know exactly what you have even though you bought supposedly a narrow trunked "Mexican fan palm".

So, unfortunately, it's hard to predict how wide across your fan palm will get even though it's called "Mexican fan palm". When these fan palms grow about 10 feet tall, the width of the trunk probably won't change a whole lot. Palms grow differently than trees and they don't get much wider with age due to a lack of secondary growth after a few years.

Even the so-called experts have trouble telling them apart!

Is this W. filifera?

Which is which? Or are they both the same?

Mexican and California fan palms gets 60 (California fan palm) to 100 feet tall (Mexican fan palm). There are other palms that stay smaller than this and are better suited to residential landscapes. These palms produce seed from the flowers in about April. If you have your palm pruned at that time of year you can have the flower stalks removed as well as the palm fronds. This eliminates seeds from being spit and germinating everywhere or landing in your pool.

Palm seedlings like this one start easily when water is present.

It's best to prune these palms every year but you could get by with pruning the fronds off every two years. Ideally you want the palms pruned so that the head of it is a half-circle. This means only removing fronds below horizontal. I would discourage you from having it pruned as a "feather duster" with only a wisp of palm fronds at the very tip. Landscape maintenance companies encourage homeowners to do that so that you can get an extra year before pruning again. I wouldn't recommend this as it weakens the palm.

Mostly Mexican fan palms pruned improperly like a feather duster.

            Personally, I think these palms are too large for residential landscapes and it's best to have them removed when they're young. It's expensive to remove them when they're older.

            By the way, they won't produce shade of any amount as they get taller, and they are water guzzlers compared to the shade they produce.

How to Prune Texas Rangers the Right Way!

Q. I am new to my home and inherited several Texas ranger bushes. Two of them are on long stems with bushiness only at the top. If I cut these way down, will they bush out, filling around the bottoms of the plant or will I kill it?

Timely Texas ranger pruning allows flowering.

A. I am sure you are not alone with this problem. The short answer is yes, they will grow from the base if cut back. But Texas rangers are slow to grow back after they have been pruned. They are not like oleanders which can grow back quickly as suckers. They don’t sucker well from the base. Instead, they prefer to force their growth on existing stems just below the cuts. It may be necessary to prune all the growth back close to the ground. Leave about 2 inches above the soil or rock for new growth to sucker from the stems.

Pruning Texas ranger with a hedge shears results

            This is a common pruning practice by landscape companies that don’t know what they’re doing. They use hedge shears about twice a year to “shape” these bushes instead of pruning them. Shaping works, but only on hedges. That’s why they are called “hedge shears”.

            If you want to do it yourself then use a sharp lopper or reciprocating saw and cut these big stems back 2 inches above the soil surface and let them sprout from the sides. If there are too many sprouts, pull them off so that only the ones you like remain. It speeds up the growth if you do that. The best time to pull them off is in the spring otherwise you must prune them off. About every second or third year, prune two or three of the largest stems close to the soil surface and let the stems regrow from side sprouts.

Will Vertical Farming Feed the World?

            Vertical farms have become one of the buzzwords at USDA for a new type of modern farming. It can allow for the growing of an acre of crops in about 300 square feet, about the same area as a shipping container. 

Freight Farms Leafy Green Machine 

It is in an enclosed environment, oftentimes super insulated, for the purpose of growing of plants. The structures for the growing of crops for vertical farms can range from retrofitted buildings to modified shipping containers. The “inputs” for a normal farm (light, air, water, fertilizer) now becomes the farmer’s responsibility, not Mother Nature because the farm is disconnected from Mother Nature. Hence the need for automation.

One method of vertical farming is using horizontal growing areas for the plants.

If you were to live inside of a vertical farm the temperature would be constant year-round, LED lights would go off and on at predetermined times, plants would be stacked upon each other, pulses of fertilizers would come and go, and irrigation might be hydroponic, aeroponic, or traditional. All these factors sensed and controlled by an electronic “brain” that controls the entire system.

Another method of vertical farming is to grow plants vertically.

But is vertical farming the boon to “feeding the world” that it claims? Is vertical farming economically viable? A lot of these answers are still up in the air because the concept is so new and what we call “vertical farms” can be so variable. Vertical farming is in its infancy.

            Ten years ago, vertical farms successfully grew many types of leafy green vegetables like lettuce, spinach, and arugula. Just as in home gardens, fruiting crops like tomatoes, squash, and raspberries were more difficult to grow. There is some discussion in academic circles whether crops grown in vertical farms aimed at “feeding the world” should be the higher-value horticultural crops or staple crops like multiple crops of wheat but with 70-to-80-day turnovers.

Most vertical farms employ hydroponics (growing in water with a substrate) much like cannabis is grown inside buildings. Hydroponic growing of vegetables may present a quality problem IMHO.

In vertical farms all the “inputs” (light, water, fertilizer) must be supplied to the plants rather than taking them for free from good old Mother Nature. Once a vertical farm is installed, these previously free “inputs” are considered “operating costs”.

Vertical farming has a future, but what that future is remains to be seen.

Problems with Rat-Tailing Pine Trees

 Rat-tailing a pine tree is removing all of the inside branches from limbs but leaving the newest branches at the end of branches. The short term advantage is that it does allow better air flow through the tree and helps prevent the tree from blowing over. 

However, shallow roots might not support the tree. Shallow roots are because of frequent watering and/or poor soil preparation at the time of planting.

Rat-tailed pine tree. It allows wind to blow through the canopy more easily and helps prevent tree blowover but it causes numerous other problems resulting in limb breakage.

Other problems may result from rat-tailing pine trees.  

Removing interior branches can result in weaker limbs because the branches that were "feeding" these limbs are removed. The branches remaining, those that the ends, continue to feed the limbs resulting in limbs that have less taper and are structurally "weaker" and subject to breakage. Several years may be needed before this is happens. Rat-tailing pine trees may result in less blow over in the short run but eventually it might also result in more limb breakage.

Loss of Pine Limbs May Be Light or Water

Q. I have a large pine tree in a natural area losing limbs from the bottom up. It’s needles are browning and dropping. I don't water the tree much at all, but I have a water channel flowing 3 feet away on one side of the tree. The channel is mostly filled with moving water and is about 1 foot wide.

A. It's probably either water or light issue. Not enough light because trees are planted too close together will also cause lower limbs to die and drop. Sometimes light is not considered.  Pine trees planted four to six feet apart are too close together and lower limbs will die as they age.

An open canopy pine tree signaling that maybe the tree was either not receiving enough water OR it cannot get the applied water to the needles due to trunk damage.

            My guess is that it's water related; not enough. An easy way to find out is to put a sprinkler on the end of a hose and give the tree one to two hours of water once every three weeks to a month. I would use a non-oscillating sprinkler and adjust it to about 8 feet wide. Use a four foot long piece of rebar to adjust how many minutes to water.

Hose-end sprinkler.

            There are two ways that I use to tell if a pine tree isn’t getting enough water; 1) I look at the amount of new growth and 2) its canopy density. On well-watered, fertilized smaller pine trees to about 20 feet tall, I like to see about 18 inches of new growth and a solid canopy density. On older well-watered pine trees 40 to 60 feet tall the growth will be a lesser amount, perhaps 8 to 12 inches, but the trees still have a dense canopy.

If growth is 2 to 4 inches when the pine tree is older then growth is not enough. Measure growth at the end of May after spring growth is finished.

            Pine trees with drought problems usually grow 2 to 4 inches in length each year. This small amount of growth translates into a very open canopy. Because pine trees can have other problems as well such as borers and woodpeckers (sapsuckers), I inspect the trunk for this kind of damage as well. A tree trunk with extensive damage by borers or woodpeckers may also show signs of drought. Pine trees with only a few inches of new growth each year and an open canopy usually suggests drought.

Get the Power of a Phone Weather App and Recording Max/Min Thermometer

Q. You suggested buying a waterproof, battery-operated recording maximum minimum thermometer for about $15. I’m having trouble locating what you’re talking about.

Taylor instruments recording maximum and minimum thermometer.

A. I suggested buying a recording maximum/minimum thermometer and placing it in your gardening area so that you could track temperatures during the late summer, fall, winter and spring. This thermometer, combined with a weather app on your phone, makes a powerful and inexpensive combination that predicts the future weather and weather that already passed. Use this information to determine tree fruit losses and the best time to prepare the soil for planting either cool or warm season vegetables.

            Placing it as close as possible to the gardening area helps you decide the low temperatures you received during the night. Watching these low temperatures tells you how cold your microclimate got in your backyard so you can accurately compare yours to other microclimates.

            Look for manufacturers with well-known names in the weather or instrument categories such as Taylor and AcuRite. Make sure the thermometer records minimum and maximum temperatures over a time period such as 10 days. Accuweather and the National Weather Service are popular phone apps.

Oak Tree Dropping Leaves Continuously

Q. We have a 10-year-old live oak tree (I think it's live oak) that was established when we moved into our home last year. I noticed that it sheds leaves seemingly all year long which didn't seem right to me. It is happening very fast now and I'm really worried.

This evergreen oak has been dropping its leaves. Look for aphids in the cool spring.

A. Yes, judging from your pictures it is southern live oak and probably Texas southern live oak; maybe ‘Heritage’.

            Let's get something out of the way quickly. That's irrigation. I know it doesn't seem logical but irrigation can, and notice I said can, be the source of a lot of problems in the desert. Live oak from Texas is not a “desert tree” but for a large tree (40 to 50 feet tall) it can use much less water than some other trees around the same height, such as mulberry. It will survive in a lawn and it will survive in rock landscapes if given enough water.

Water larger plants like large trees deeper than smaller trees and shrubs. To wet the soil deeper and NOT adjust the number of minutes, add more emitters.

            Whereas mulberry might require between five and 6 feet of water under its canopy each year, Texas Live Oak can still look good with 3 to 4 feet of water applied to the same area. Watering too often, not watering often enough, giving the tree not enough water all at once, and not distributing the water over a wide enough area under the tree can cause leaf drop. When water is applied to Texas live oak, it should be applied to at least half the area under the canopy and to a depth of 2 ½ feet. It is watered again when the upper six to 12 inches starts drying.

            The usual spring problem on live oak are aphids. If heavily infested the leaves will fall or drop. Aphids becomes a lesser problem when it gets hot. Trees with leaves infested with aphids are easy to spot because aphids leave a sticky residue on the leaf surface and can cause leaf drop when they feed on plant sap. The sticky residue glistens in the sunlight. An application to the soil in the spring of a systemic insecticide like imidacloprid or a rose systemic insecticide will take care of the aphids and stop the excessive leaf drop.

Sick Oak Tree and Its Spring Recovery

Q. I have a sick oak tree in our backyard. It is an older tree and but not growing well. Our gardener suggested hiring an arborist to treat the tree and help it recover. Can we purchase something to correct this? Would an arborist be able to save it? Your thoughts.

Sick Oak tree trunk in the backyard. 'Heritage' live oak is a good tree choice for two-story homes in Las Vegas.

A. From the picture you sent it looks like a southern live oak such as 'Heritage'. It looks like the trunk of the tree is slow to recover and has some pretty old wounds. Getting it to recover depends on how far “gone” it is. You will not know that until the summer hits. Even though it's a 30 to 40 foot tree (size-wise think of it as a bit larger than European olive). This particular oak is classified in between xeric and mesic and a native to southern Texas and into the Chihuahuan desert. It does well where there is a bit more water and also into the drier locations. The "cons" of this tree

       All oaks like amended soil and don’t like the soil “mineralized” by rock mulch over time. Rake the rock back three feet from the trunk. Change this area over to a layer of organics that can rot on top of the soil. Add a thin layer of finely screened compost to the soil. Water the tree two feet deep once a week right now. This can be done with a sprinkler on the end of a hose. This may be increased to twice a week if it gets hot and windy.

            Oaks in general dont like rock up to the trunk but prefer growing in soils getting organics periodically. Rocks cause the soil to become “mineralized” over time (organics in the soil are lost to decomposition). This is the reason for adding compost and wood chips to the top of the soil.

Tree roots require deeper irrigation. The bigger the plant, the deeper the roots. Use a length of rebar to judge how to deep to water. To get water deeper with the same amount of time, add more drip emitters!

            Secondly, this tree needs additional water each time its irrigated; 15 to 20 gallons during the first few years but now may be 30 to 40 gallons each time. Instead of increasing or decreasing the minutes, add more and larger drip emitters to the area under the tree. Put sprinkler hose water into a 6 to 8 foot wide area under the tree for about one hour and encourage the roots to “chase” the water into this newly wetted area. This will increase the trees vigor and cause it to heal fast. No need for additional fertilizer if the compost is rich with nutrients.

            If you see evidence of borer activity from previous years, it probably was reinfested each year since that time. Soil drench the area under the tree with a borer systemic insecticide. Apply it as a soil drench after the tree finishes flowering.

Soil Iron Fertilizer Applications End About April-May

As I mentioned before, we are nearing the end of any soil applications of iron fertilizers that work. You can still do it now but don’t expect glorious results like you would see when you apply it at the beginning of new growth (spring). 

Soil applied iron applications will end about April-May as new growth slows down and finishes.

These iron fertilizers and include Kerex, EDDHA iron chelates and any other iron fertilizers meant to be applied to the soil. 

Kerex iron application was made to the soil near this plum in April of 2015. Didnt work. Should have used EDDHA iron chelate or more of the Kerex or added compost AND then applied Kerex.

If there is not enough soil "organics" to decompose then any iron fertilizer will work. Decomposition of organics in the soil lowers its alkalinity and makes just about any iron fertilizer work. Bottom line, be careful greening up plants that have been growing in rock mulch more than three or four years.

Once early spring through early summer has passed, the only thing that cures leaf yellowing are the leaf sprays applied directly to yellowing leaves. 

This chelate is iron EDTA, not EDDHA. EDTA chelated iron works well IF the soil alkalinity (pH) is 7.6 or below. For any iron to work well also requires that nitrogen fertilizer is present. Always apply iron chelates with a well fertilized plant OR include a nitrogen fertilizer at the same time.

Iron sprays like this one are less expensive but you MUST adjust the water chemistry either by adding

 a cup of vinegar (acetic acid) to a gallon of water or use distilled/deionized water.

That’s a poor substitute for soil applications of iron, best done earlier in the season (late January- March) but sometimes the yellowing is so severe it must be done when it’s seen.

Sometimes the yellowing of plants is so severe that an iron application, either applied to the soil or sprayed on the leaves (or both), is necessary to prevent death or injury to the plant.

            Just remember the alkalinity of our tap water is very, very important to a spray’s effectiveness so either adjust the alkalinity of tap water with a cup of vinegar for each gallon or use distilled water for your iron spray.

            Regarding applications of fertilizer, do the trees really need it? It’s best to apply plant growth fertilizers in the spring but applying it now, if desperate, is still better than nothing. Applying fertilizers when trees don’t need it is a waste of fertilizer, a waste of money and unhealthy for the trees.

New growth in apricot. Excessive. Should be an average of about 18 inches.

 Look in several locations at the color of the leaves and the amount of new growth. If the leaves are a very dark green and new growth is exploding, your trees don’t need a fertilizer application. Save the fertilizer application for next February or, least wise, the November coming up.

Dense canopy of a fruit tree. Add no fertilizer this year.

Desert Horticulture: Iron Applications Differ in Timing and Product Used

 Iron applications are applied to the soil earlier in the year and sprayed on leaves later in the year. Learn why and how on this episode of Desert Horticulture.

Interveinal chlorosis (yellowing) on apricot growing on a desert soil.

Desert Horticulture: Fireblight Disease on Fruit Trees and Other Landscape Plants

Learn how to discover if your landscape plants and fruit trees have Fire Blight Disease or not.All this and more on this episode of Desert Horticulture.

Fire Blight disease, bacterial in nature, occurs in orchards and landscape plants after strong blowing winds.