Wet soil or mulch against tree trunk can cause collar rot

Q: The leaves on my fig tree appear burned after this rain. I foliar sprayed it with neem oil and soap and fish protein isolate. These trees were planted last fall and mulched with 1 foot of woodchips and looked amazing until now. They are watered three times each week in the summer.

A: The leaves look like they are diseased. But I have a saying: “When the top looks bad, look at the ground.” Eliminate the easy problems before jumping to more difficult ones.

I wonder if that 12 inches of surface mulch is rotting the trunk of the tree. It is easy to kill young trees if they sink into the planting hole after planting. Or if woodchip mulch on the soil surface is piled against the trunk and kept wet.

In both cases, wet soil or wet mulch against the trunk can cause a disease called collar rot. The disease rots the trunk and chokes the top of the tree. When this happens, leaves look diseased or not getting enough water. This becomes very apparent during hot weather.

Start on your knees and pull the mulch away from the trunk. Keep it there permanently, 6 to 12 inches away. Next, carefully remove the soil from around the trunk until you find tree roots coming from the trunk growing horizontally.

If this small area of the trunk looks water-soaked, there might be a problem. I take a penknife and cut away a narrow strip of the trunk that was buried in soil and mulch. The wood under the strip should be white or greenish white.

If there is more than a half-inch of soil covering the trunk, or the trunk was buried in wet mulch, the tree may develop collar rot. All you can do is let the covered part of the trunk air dry and hope for the best.

I have seen collar rot develop on the lower trunk of young figs and pomegranate that are buried. Most figs and pomegranates are grown on their own roots. If the top of the tree dies, wait a couple of months and see if anything suckers from the roots or base of this tree. If it does, don’t replace the tree.

These basal suckers will grow very rapidly into a new tree because the tree already has established roots. When one of the suckers is 12 inches tall, remove the others for a single trunk tree or select three to five for a multitrunk tree.

It’s possible these leaf problems are related to a leaf disease, but I don’t recognize it. Sometimes when dead areas develop from disease pathogens, the dead area is bordered by yellow. This yellowing is where the plant tissue is still dying. Sometimes this yellowing doesn’t exist but only because the disease has stopped spreading.

The humidity in Las Vegas is unusually high right now because of the summer monsoon and rains. I expect diseases to pop up during this kind of weather. Having leaf diseases on fruit trees would not be uncommon during this time of year.

Instead of spraying, try using a passive approach toward controlling diseases. Remove extra leaves that might be blocking the movement of air and wind through the canopy. As you see leaf diseases, remove the infected leaves and dispose of them. The plant will grow new leaves in places where there is sunlight. Leaf diseases slow down or stop as the weather changes.

Q: The cycad I bought in a container a few years ago is turning yellow even though I moved it out of direct sun and into the dappled shade of a vitex tree. Can you advise whether I still need more shading to correct the yellowing? I’m afraid to plant it in the ground because it might freeze.

A: I don’t think the yellowing is a problem from intense sunlight. This plant can handle full sun in our Mojave Desert with no problems if the soil has been prepared adequately, organic amendments are added to the soil every year or two and water is available when needed. It’s easier to grow, however, on the east side of buildings where it gets some protection from the late afternoon sun.

From your picture, it seems it is growing in the same container that came from the nursery. If this is true, all the organics in that original soil are gone. Even if you are adding fertilizer to the container, the plant leaves yellow because the soil is worn out. Basically, the plant is growing in the container hydroponically (only water and whatever fertilizer it gets).

It is important to add organic amendments to all soils on a regular basis to maintain good plant health, improve its tolerance to our harsh desert climate and ensure plants are resistant to diseases.

Plants grow better and are healthier (they can withstand more problems) if they are grown in the ground and in a healthy manner. Your cycad is growing in old, tired soil that has not been amended in a container that’s too small, and who knows if it’s getting water when needed?

Pick a spot for it and get it planted. Plants growing in containers are difficult to manage. In the ground, it can grow in full sun if surrounded by other irrigated plants. This plant will be healthier if the soil is covered with woodchips rather than rock. It is not a desert plant for sure, so it needs to be planted and watered with other nondesert plants and cared for in a nondesert way.

These plants will tolerate temperatures as low as 20 degrees but may show some winter damage (bronzing) to the leaves at 25 degrees. Remember, winter cold is worse if the plant is growing in a windy location.

When planting it this fall, use a quality compost and mix it equally with soil taken from the planting hole. Use this amended soil and flood the hole with water as the soil is added. Make sure it’s planted at the proper depth — not too shallow nor too deep.

Cover the soil surrounding it with woodchips from local trees trimmings. These will degrade over time and add more organics to the soil. Your cycad will appreciate this.

Fertilize it lightly once a year with a tree, shrub or lawn fertilizer. Apply it under the leaves, not too close to the trunk, and water it in.

Leaves that are yellow will stay yellow until removed in a couple of years, when the plant gets older and bigger. But the new growth coming from the trunk should be dark green if planted correctly. This new growth eventually replaces yellow leaves as they are removed.

Water the same as you would other trees and shrubs in the landscape. Apply 5-10 gallons of water each time it is irrigated.

Q: I found many holes scattered in bare ground at one of the properties I maintain. The holes are small, perhaps the size of a penny. I hope you can help me identify what could be doing this. I don’t want to hurt any pollinators.

A: It’s mid-July now, and I have been hearing the buzz to attract females from male cicadas since around the first of the month. I think what you are seeing are emergence holes of cicadas. The immature cicada grub lives underground and feeds on tree roots such as ash.

Most people know the 17-year periodical cicadas, but there are other cicadas that emerge every year. The cicadas are nicknamed “dog day cicadas” or annual cicadas because they emerge every year during the heat of summer.

That buzzing noise is used to attract females for mating and eventual laying of eggs. The eggs of cicadas are inserted by females into slits cut into small tree branches. Sometimes the small branches die from the damage caused by an egg-laying combined with the heat of the summer.

The eggs hatch and the small young drop to the ground, where they dig deep into the soil to find plant roots, sometimes as much as 6 to 8 feet below the surface. They have powerful front legs modified for digging deeply into the soil to find roots for food and water.

You should be able to see their empty discarded skins split open on tree trunks, the sides of buildings and other structures. I wouldn’t worry about them, but I expect it’s important to remove cast skins when you see them because of aesthetics.

I have never heard of anyone controlling them because of plant damage.

Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.

New MLK freeway on-ramps
How to navigate the trio of new freeway on-ramps from Martin Luther King Boulevard. (Mick Akers/Las Vegas Review-Journal)
Extreme weather closes Scenic Loop in Red Rock Canyon
High winds and flooding closed the Scenic Loop in Red Rock Canyon National Conservation area Thursday. Minor flooding across Highway 159 caused drivers to slow, but didn't close the road. (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
Learning live-saving techniques in Stop the Bleed class
Leslie Shaffer, an AMR paramedic, shows how to control bleeding during a Stop the Bleed course at the Summerlin Library. The class is designed to teach anyone how to control and stop life-threatening bleeding. (Mia Sims/Las Vegas Review-Journal)
Mount Charleston Gets Heavy Snow, Fog
Mount Charleston saw heavy snow today, and fog in lower elevations as a cold front swept across the Las Vegas Valley. (Benjamin Hager/Las Vegas Review-Journal)
Tourists enjoy rain in downtown Las Vegas
Tourists break out the umbrellas. But Brian Herting of Lincoln, Nebraska, dons shorts and a T-shirt, as he makes his way through downtown Las Vegas. (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
Thick fog blanketed Las Vegas Valley on Tuesday
Thick fog blanketed Las Vegas Valley on Tuesday. The National Weather Service.forecast called for a 50 percent chance of rain. (Bizuayehu Tesfaye/Las Vegas Review-Journal) @bizutesfaye
Time lapse video of fog covering the Strip
The Las Vegas Strip is shrouded in fog Tuesday, Jan. 15, 2019. (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
Tony Spilotro's Las Vegas home for sale — VIDEO
The former Las Vegas home of Chicago mob enforcer, Tony Spilotro, is now for sale. Spilotro, who was portrayed by Joe Pesci in the film Casino, is the original owner of the home at 4675 Balfour Drive, built in 1974. (Samia DeCubas/Las Vegas Review-Journal)
Buffalo Drive And Mountains Edge Parkway Fatal
Las Vegas police and the Nevada Highway Patrol are investigating a fatal crash in the southwest valley on Saturday afternoon. (Richard Brian/Las Vegas Review-Journal)
UNLV's Joel Ntambwe on his play
UNLV forward Joel Ntambwe talks about his play at this point in the season. Video by Mark Anderson/Las Vegas Review-Journal
Sam Schmidt chats about hectic off-season
IndyCar team owner Sam Schmidt and lead driver James Hinchcliffe chat about the hectic off-season at the SpeedVegas high-performance driving facility outside of Las Vegas, Nevada, on January 10, 2018. (Ron Kantowski/Las Vegas Review-Journal)
R-J's Mark Anderson on UNLV's victory
Review-Journal sports reporter Mark Anderson recaps UNLV's victory at New Mexico. Video by Mark Anderson/Las Vegas Review-Journal
UNLV's Noah Robotham on the win at New Mexico
UNLV guard Noah Robotham talks about winning at New Mexico on Jan. 8, 2019. (Mark Anderson/Las Vegas Review-Journal)
UNLV's Kris Clyburn on big 3 vs. New Mexico
UNLV guard Kris Clyburn talks about his key 3-pointer against New Mexico. (Mark Anderson/Las Vegas Review-Journal)
Marvin Menzies on beating New Mexico
UNLV basketball coach Marvin Menzies talks about UNLV's win at New Mexico on January 8, 2019. (Mark Anderson/Las Vegas Review-Journal)
New HOV Ramp Scheduled to Open in March
New HOV ramp scheduled to open in March of 2019.
American Preparatory Academy part of charter school growth in Las Vegas
American Preparatory Academy in Las Vegas has a waiting list of students who want to attend. (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
Wheelchair tournament at UNLV
Cesar Robledo talks about wheelchair basketball and what it means for players to compete during the Wheelchair Basketball Division I-II Tournament at UNLV in Las Vegas, Sunday, Jan. 6, 2019.
Snow in Henderson on New Year's Eve morning
Light snow flurries in Anthem Highlands in Henderson on Monday morning, the last day of 2018.
Marvin Menzies on UNLV's trip to Hawaii
UNLV basketball coach Marvin Menzies talks about the upcoming trip to Hawaii. Video by Mark Anderson/Las Vegas Review-Journal
Raiders Stadium Timelapse
Construction on the new Raiders stadium continues in Las Vegas.
Pinecrest Academy Horizon principal wins Milken Educator Award
Tony Sanchez on UNLV's recruiting class
UNLV football coach Tony Sanchez talks about his early signing class. Video by Mark Anderson/Las Vegas Review-Journal
The Magical Forest at Opportunity Village
Opportunity Village's Magical Forest added 1 million lights and a synchronized music show visible from all over the forest this year. The holiday attraction, which began in 1991, has a train, rides, food and entertainment along with the light displays. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Siegel Cares delivers bagels to families in need
Since Thanksgiving, Mark Lenoir of Siegel Cares, has been delivering leftover Bagelmania bagels to families staying at the Siegel Suites.
Dan Barnson steps down
Arbor View football coach Dan Barnson stepped down Friday after 12 seasons at the helm. Under Barnson, the Aggies won 104 games and became one of the top programs in Las Vegas. The Aggies went 12-2 in 2018 and won a region championship for the first time in program history. Barnson loves Friday nights, but said the 12-month commitment was getting exhausting.
NFR 2018 Highlights
NFR 2018 highlights from every round of this years rodeo.
NFR 2018 Round 10 Highlights
NFR 2018 Round 10 Highlights of the 2018 Wrangler National Finals Rodeo from the Thomas & Mack in Las Vegas, Nevada. (CBS Sports Network/PRCA)
NFR- Joe Frost
NFR Bull Rider Joe Frost talks about the difference in bulls and his family legacy with Cassie Soto before the last round of the National Finals Rodeo.
Herm Edwards on LV Bowl loss
Arizona State coach Herm Edwards talks about the loss in the Las Vegas Bowl. Video by Mark Anderson/Las Vegas Review-Journal
Tony Sanchez wraps up the UNLV season
UNLV football coach Tony Sanchez wraps up the season. Video by Mark Anderson/Las Vegas Review-Journal
Barber sets up shop in grandfather’s old shop
Andres Dominguez’s new barber shop is filled with memories of his grandfather, who ran the El Cortez landmark for more than 30 years. (John Przybys/Las Vegas Review-Journal)
Life and times of a 90-year-old horse player
Leo Polito of Las Vegas describes meeting legendary jockey and trainer Johnny Longden on the beach at Del Mar. Mike Brunker/Las Vegas Review-Journal.
Learning the history of singing bowls
Presentation at Summerlin Library teaches residents about the history of singing bowls (Mia Sims/Las Vegas Review-Journal)
Learning live-saving techniques in Stop the Bleed class
Leslie Shaffer, an AMR paramedic, shows how to control bleeding during a Stop the Bleed course at the Summerlin Library. The class is designed to teach anyone how to control and stop life-threatening bleeding. (Mia Sims/Las Vegas Review-Journal)
Vicki Richardson speaks about on the power of art
Artist and arts advocate Vicki Richardson talks about the power of art to inspire and challenge. (John Przybys/Las Vegas Review-Journal)
DressCoders pairs tech with haute couture
DressCoders is a startup focused on haute couture garments. The company uses illuminated thread that is washable and can be sewn right into the fabric. (Mat Luschek/Las Vegas Review-Journal)
CES 2019: Brava infrared oven
In cooking with the Brava infrared oven,there’s no preheating. the bulbs can reach 500 degrees in less than a second. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Sinks Merge Style And Utility
Study could determine cause of Alzheimer’s, Parkinson’s diseases
Dr. Aaron Ritter, director of clinical trials at the Cleveland Clinic Lou Ruvo Center for Brain Health, discusses his research on how inflammation in the brain impacts Alzheimer’s and Parkinson’s diseases. (Jessie Bekker/Las Vegas Review-Journal)
Holocaust survivors talk about tragedy and friendship
Janos Strauss and Alexander Kuechel share their perspectives on life. (John Przybys/Las Vegas Review-Journal)
'Siegel Cares' Santa delivers toys to kids at Siegel Suites in Las Vegas
Siegel Cares, the charitable wing of The Siegel Group, delivered toys to families at their apartment complexes in Las Vegas. (K.M. Cannon/Las Vegas Review-Journal)
Revisiting “Christ the King” sculpture
A longtime admirer of the sculpture at Christ the King Catholic Community in Las Vegas shares her perspective. (Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye)
Henderson couple adds another school to their generosity
Bob and Sandy Ellis of Henderson, who donate to several Clark County School District schools, have added Matt Kelly Elementary in Las Vegas to their list of schools where every student gets new shoes, socks and a toy. (K.M. Cannon/Las Vegas Review-Journal)
Terry Fator Christmas House
Arguably better than a hotel holiday display, is Terry and Angie Fator's home located in southwest Las Vegas.
UNLV Winter Graduation Packs Thomas & Mack
UNLV's 55th winter commencement ceremony included approximately 2,146 undergraduate and graduate students who recently completed their studies. (Benjamin Hager/Las Vegas Review-Journal)
Build-A-Bear comes to Reed Elementary School
Students participated in a Build-A-Bear-Workshop at Doris Reed Elementary School in Las Vegas, Thursday, Dec. 13, 2018.
Rev. Father Seraphim Ramos talks about Greek Orthodox icons during an interview with the LVRJ
Rev. Father Seraphim Ramos talks about Greek Orthodox icons during an interview with the Las Vegas Review-Journal at St. John the Baptist Greek Orthodox Church. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Masjid Ibrahim Islamic Center art depicts names of God
Masjid Ibrahim Islamic Center founder Sharaf Haseebullah talks about new diamond-shaped art panels featuring some of the 99 names of Allah at the main entrance the Las Vegas mosque. (K.M. Cannon/Las Vegas Review-Journal)
Holiday poultry with Tim and Chemaine Jensen of Village Meat & Wine
Tim and Chemaine Jensen of Village Meat & Wine explain the different types of poultry available for the holidays. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Catholic Charities hosts early Christmas meal
Students from the Bishop Gorman High School football and cheerleader team helped to serve food at the Christmas meal sponsored by the Frank and Victoria Fertitta Foundation at Catholic Charities of Southern Nevada on Sunday. (Rachel Aston/Las Vegas Review-Journal)
Incarcerated Christmas
This is the fourth year HOPE for Prisoners has worked with the Nevada Department of Corrections to create a Christmas for prisoners to visit their families. (Rachel Aston/Las Vegas Review-Journal)
2018 Homeless Vigil
Straight From The Streets holds its 23rd annual vigil to remember the 179 homeless individuals who died in Clark County this year.
Getting through the Holiday blues
Psychologist Whitney Owens offers advice on keeping your mental health in check during the Holiday season in Henderson, Thursday, Dec. 13, 2018. (Caroline Brehman/Las Vegas Review-Journal)
Operation Homefront Holiday Meals for Military
Operation Homefront Holiday Meals for Military program gave meal kits to 200 families at Veterans of Foreign Wars Post 10047 in Las Vegas Wednesday, Dec. 12, 2018. It all started with a chance encounter in a supermarket in Utica, N.Y., near Fort Drum. A soldier, his wife and infant had a handful of grocery items they couldn't afford. A Beam Suntory employee picked up the $12 cost for the groceries. The program has grown from providing 500 meal kits to military families in 2009 to providing more than 7,000 nationally this holiday season.K.M. Cannon Las Vegas Review-Journal @KMCannonPhoto
An elegant Tea Party for substance abuse and homeless women
An elegant Tea Party for substance abuse and homeless women at WestCare Women Children Campus in Las Vegas. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Former 51s manager Wally Backman chats about new job
Former Las Vegas 51s manager Wally Backman talks about his new job with the independent league Long Island Ducks during the Baseball Winter Meetings in Las Vegas, Nevada, on Dec. 10, 2018. (Ron Kantowski/Las Vegas Review-Journal)
Inside the kitchen at Springs Preserve
The staff of Divine Events do party preparation in the kitchen at Divine Cafe at Springs Preserve. With nine parties the following day, this is a particularly busy time for the crew. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Pearl Harbor survivor Edward Hall talks about his memories of Dec. 7, 1941
U.S. Army Corps Edward Hall, a 95-year-old survivor of Pearl Harbor talks about his memories of that horrific day. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Roy Choi on cooking for Park MGM employees
As he prepares to open his new restaurant Best Friend later this month at Park MGM, celebrity chef Roy Choi took the time to cook for the resort’s employees Tuesday. (Al Mancini/Las Vegas Review-Journal)
Best Friend Menu Reveal Wednesday
Chef Roy Choi tells us what to expect from Wednesday’s Facebook Live Menu Reveal for his new Park MGM restaurant Best Friend. (Al Mancini/Las Vegas Review-Journal)
News Headlines
Home Front Page Footer Listing
You May Like

You May Like