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Tuesday, July 25, 2017

Pomegranate Yellowing and Leaf Drop

Q. A combination of overwatering and this heat caused my 9-year-old dwarf pomegranate leaves to yellow and drop on about 1/3 of the plant.  I turned off the water and hand watering it with small amounts of water. The only thing I did differently was give the plants a small dose of MiracleGro in the spring. Any suggestions? 
This pomegranate does not look all that healthy. The leaves should be much darker green. Probably watering too often caused it and the dieback. Use more water and apply it less often. Let those roots breathe!

A. This is not your common ordinary disease problem. It is humanitis! And the fertilizer did not cause it either.

Pomegranate is remarkably resilient in our climate if it’s not watered too often. Avoid watering these plants daily. Give it plenty of water when you irrigate and then hold off until the next irrigation. I water newly planted trees this spring every other day when temperatures are above 110° F.
Here's a pomegranate yellowing. Why? Because it was planted in a lawn that needs watering every day.

Watering once a week is enough in early spring and late fall. As it gets warmer, water more often. You should never have to water more than once every other day in the hottest weather!
            Leaf yellowing and drop can be a temporary problem with many fruit trees regarding water issues. Give the plant some time to respond if these branches are still supple and bend easily. 
            If these branches have dried and appeared dead, cut them off just above healthy growth. I have removed damaged parts during the summer months and the plant re-grew without problems.
            Use wood chip mulch on the soil surface to help preserve soil moisture during the heat. This gives me one extra day between waterings. I am giving new plants about 5 gallons, 3-year-old trees about 10 gallons, 5-year-old trees about 15 gallons and trees over 8 years old from 20 to 30 gallons depending on their size. A dwarf, 9-year-old tree is going to be in the range of 10 to 15 gallons each time you water.
            I have had no problems with loss of leaves during the summer but some of the 20+ varieties I have grown had winter cold damage. Some varieties of pomegranates, particularly those with Russian names, showed some winter cold damage. Older, common varieties sold for many years in the American market sailed through cold winters down to 10° F.

Shrub Dieback Due to Excessive Heat and Lack of Water

Q. I have several really tall thick pittosporum plants - some well over 7 feet tall and usually thick with foliage, but this year they seem to have suffered a LOT from the heat.  I checked at the base and the most damaged one -- down to a mere skeleton -- is getting water.  They are about 20 years old -- is there an "age limit" to plants like these?
Thats a good looking full-sized Pittosporum with good leaf color. Obviously healthy.

Are they THAT heat sensitive?  I'd hate to lose them all.  When, and how severely, should I prune?  Take the more damaged ones back down to sticks and hope for recovery?

Drought on Pittosporum due to high temperatures and wind.

A. That is what a full-sized Pittosporum is supposed to look like. I like the color in the form of the undamaged plant. 

The damage top and suckering from the base tells me the plant is putting on some new growth where it is easiest for it. When everything is optimum, the plant will always try to get larger and put new growth as high as it can. When conditions are not optimum, then it will try to put on growth in places where it spends the least amount of energy and trouble. 
Sprouting occurred due to the cuts made on the stems and the stem exposure to sunlight combined with...thats an easy place for the plant to put on new growth. You remove something and it will try to regrow in that spot to get that energy from the sun.

The damage at the top in the suckering at the base tell me the plant is not getting enough water when it is watered. Plus it was opened up with some pruning cuts at the base. I would add 2 or 3 more drip emitters to the base of that plant and try to cover at least half of the ground under its canopy with water. This means spread the drip emitters out about 12 to 18 inches apart under its spread. 

I would also put about one bag of compost under the large plants and water it in with the hose. Keep the area wet for the following 1 to 2 weeks. I think you will see a change in 2 to 3 weeks. Prune out the dead branches by cutting at a Y or joint between the dead branch and a living branch deep inside the canopy, 8 to 10 inches inside of it.

Monday, July 24, 2017

Fiddleleaf Fig Care Prevents Diseases

Q. My fiddleleaf fig houseplant has brown spots on some of the leaves. I'm watering it every other week. I have looked but can't find the cause of these brown leaf spots. I thought it might be a fungal issue, so I applied liquid copper but that didn't make any difference. Do you have any idea what causes these spots and what I can do to help this houseplant?

I really appreciate it when I am sent so many pictures. This helps a lot in diagnosing the problem.Fiddleleaf fig, Ficus lyrata
A. Fiddle leaf fig has made a comeback. It used to be very popular 40 to 50 years ago. Now it’s on the rebound for interior designers as a houseplant.
            Fiddle leaf fig in the wild starts its life as an epiphyte, similar to orchids. Eventually they root into tropical soils and live their life as a small understory tree, strangling the mother tree. Which means it likes filtered and indirect light. It can tolerate periods of time without soil moisture as well.
            Brown spots on leaves can be a disease problem, particularly if they are closely associated with leaf veins. Plant diseases on houseplants are not common in desert environments because of our low interior humidity. 
            Insects feeding on these plants are a bigger problem. Inspect the plant for spider mites, scale insects, mealy bugs and fungus gnats living in the soil which can cause problems similar to diseases.
            Plant diseases are closely associated with the health of the plant. To improve its health, and ability to ward off diseases, make sure it gets adequate light, water and fertilizer. If you need to stake this plant so it stands upright in a container, it is a good indicator it has not been getting enough light in the past.
            Lack of light is a common problem for houseplants because of our dark interiors. Larger houseplants slowly decline, beginning around 6 months after they are plunged into dark interiors. Smaller plants decline more quickly. If they are large plants, they have enough stored food to live for several months before they decline.
            This plant requires placement near a bright window but not in direct sunlight. Once a month turn the plant so that different sides of the plant receive light.
            When temperatures are pleasant outside, place this tree in a sheltered area on the north or east side of the home under a tree. During this time, it can start building up its food reserves for that long, dark haul inside the home during summer months. Never place it in direct sunlight which damages the leaves and causes them to drop.
           Lift the container. It is dangerous to water on a schedule unless you are confident this schedule fits the needs of the plant. Watering of this plant can be withheld until the soil is quite dry. Instead, lift or tip the container to judge its water content. Water is heavy. Potting soil containing water is much heavier than dry soil.
            Use a pencil. Sticking the pointed end of a pencil in the potting soil can help judge the moisture content. Pencils slide into moist soil much easier than dry soils.
            User soil moisture meter. They cost about 10 bucks at any nursery or garden center. They are good for judging relative amounts of water but not exact amounts of water. This moisture meter will tell you if the soil is dry enough to water or if it’s still wet and should not be watered.
            Avoid using straight tap water. Our tap water has lots of salts in it. Instead, use distilled or reverse osmosis water and blended with tap water 1:1 or more dilute. Give it enough water so that one 4th of the applied water comes out the bottom. This helps remove salts.
            Add fertilizer based on the growth of the plant. If the plant is growing rapidly, temperatures are warm and there’s lots of light, water and fertilize more often. Add a small amount of fertilizer to the irrigation water at every 3rd or 4th watering.
            Interior plants should be repotted every 3 to 4 years. This means gently lifting the plant from its container and shaving off a 1 to 2 inch layer of soil from the root ball on all sides. Use a sharp, sanitized knife. Disinfect the container and repot the plant using new potting soil.

Apricot Leaves Dried-Up in Midsummer

Q. A few days ago I noticed that most of the leaves on my apricot tree had withered and turned brown. The same thing, to a lesser degree and later in the season, happened last year. But in the spring it brought forth an abundance of blossoms and fresh, green and healthy looking leaves and produced lots of good fruit. I checked the soil, and it is not dry, but slightly moist. I am watering daily on a drip system for 35 minutes. So, wondering if you have any idea what is causing this and if I should be concerned.

This is most likely NOT borer damage. Borers typically ravage a single limb. This is over most of the tree. That most likely puts the cause in the trunk, roots or soil.
A. I looked at the pictures and 3 things come to mind right away. These center around daily watering which is a no no, the rock mulch I see around the tree and the possibility that not enough water is being distributed to serve all the roots. I don't know how much water you are giving the tree but I think the tree is running out of water before the next irrigation. I also think the rock mulch under the tree is terribly hot.

First, is the rock mulch. I like rock mulch when it is used around desert plants. I don't like rock mulch very much when it is used around non-desert plants such as fruit trees. I think you would help the tree a lot if you could rake back the rock a distance of about 3 or 4 feet from the tree and put a layer of 3 to 4 inches of wood chip mulch instead. You can get this free in North Las Vegas from the University Orchard or from Cooperative extension just south of the airport.

Daily watering of trees during the summer is not a good thing. If you can apply more water to the trees and then wait one day before your next irrigation it would be helpful. Tree roots begin to suffocate when water is present in the soil all the time. Giving the soil a chance to dry and admit some air to the roots can be quite helpful to the tree.

When the tree is watered, water should be applied to at least half the area under the canopy of the tree. This may require you to add more drip emitters then you have. A tree that size should have at least 5 to 6 drip emitters and would do better if there were more than that. These emitters should be placed about 2 feet apart under the canopy and about 18 inches from the trunk. 

A tree that size probably requires about 15 to 20 gallons every time you water. This means if you have 6 drip emitters, they should be 3 gallon per hour emitters if you are watering for one hour. If you are watering for 30 minutes, you should use 5 gallon per hour emitters.

The Perfect Apricot Storm. Borers.

Q. During the past month of high heat one limb on our apricot tree appears to have died.  All the leaves on this limb dried up while the other leaves on the tree stayed green. The limb is about 1-1/2 inches in diameter near the base.  In addition to rough discolored bark there are a couple of amber-orange blobs of sap in this area of the limb (photos attached).
This borer infested limb can be replaced in three years or less in our climate and in production in three to four.

Any hope the limb will survive and recover next season? Should the limb be cut off now?  Could this be a disease that will spread to other limbs?

A. Paul. You have described perfectly the symptoms of boring insects (borers) in fruit tree. One limb dies while the others are healthy and frequently there is sap coming from the limb in blobs or round balls.
There's the little varmint! Under the thumb.

Take a sharp knife and remove the bark where you see the sap. If you are confident the limb is dead, remove all the bark down to where the limb is still alive. Cut the limb off in this area and hopefully the remaining stub will resprout with some suckers yet this year that can, eventually, replace the dead limb. With some TLC that can happen in three years or less.

This winter select three or four of these suckers as possible candidates to replace the dead limb. Next growing season you will make your final selection of one or two to replace the dead one.

No insecticides will do much good on these. The insect is most likely gone and the limb is dead. Cut and replace the dead limb with new growth.