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Wednesday, December 6, 2017

Ants Not Good Guys in Fruit Production

Q. I searched your blog but could not discover if ants are good pollinators or not. I know bees are. I have over 2 acres in Sandy Valley and have seen 6 to 8 different types of ants scurrying about the property. Are ants beneficial or will they become a problem for fruit trees I am planting? 
Ants and aphids living and working together on apricot. The aphids suck plant juices and release sugary excrement. The ants use this sugary excrement as a food source and take it back to their nest in the ground. Ants move aphids to new locations in the tree or neighboring trees that are touching to expand their "herd" of aphids.
A. The best pollinators for fruit trees, hands-down, are honeybees. More specifically Italian honeybees, the type that produce honey collected by beekeepers. They are workhorses when it comes to pollinating fruit trees and vegetable gardens.
Female leaf cutter bees cut nearly perfect circles in the leaves of many plants including grapes and fruit trees. These leaf circles are used by the bees for raising their young.Leaf cutter bees are good pollinators of late season flowering plants.
            Other types of bees, solitary bees like the leafcutter which cuts near perfect circles in the leaves of roses, grapes and basil, are strong workers later in the year and important pollinators for late spring and summer bloomers like alfalfa and clover.
Rosemary is a good winter and early spring flowering plant to encourage pollinators for spring pollination of fruit trees.
            Ants don’t contribute anything to pollination of fruit trees in my opinion. I consider them mostly nuisance insects that contribute to insect problems in fruit trees in a secondary way. How? They love aphids and will defend them to their death against anything or anyone that threatens aphid populations.
This short video is taken at our family farm in the Philippines. It shows Weaver ants, that create their nests in the canopies of trees, protecting some scale insects they have moved and are now farming on the branches of tropical fruit trees. Ants do the same thing in temperate environments but most of our ants have nests in the ground.
            In fact, ants distribute aphids throughout a fruit tree canopy similar to how we move cattle to new pastures. Aphids are common in the spring of the year feeding on new growth of fruit trees. Their feeding causes leaves to become sticky, roll and curl. Ants move mother aphids around to increase populations and their own food supply for subterranean nests.
            While feeding on plant leaf juices, aphids drip sugary excrement that ants use for food inside their colony. Next time you find an aphid problem in fruit trees, look at the ground nearby. You will see an “ant mound”, an opening to a subterranean ant nest. There is a good reason for their close association to aphids.
            For this reason, I don’t like ants in orchards and I make a point of eliminating ant colonies when I see them near fruit trees. Several methods can be used to eliminate them but I find ant baits, taken back inside colony, to be among the most effective. Seldom are ants beneficial when growing plants for human food.

Can't Get My Trashcan Compost Started

Q. I’m composting in plastic trash cans with holes. It’s taking a very long time to make compost despite adding carbon to my grass clippings and kitchen waste. I water and turn it every few days. What am I doing wrong? 
Compost piles need to be a certain size for them to be efficient enough to generate the heat needed for weed free and pathogen free compost.

A. Compost ingredients are divided into two categories; “brown” ingredients which are loaded with carbon, and “green” ingredients which have much more nitrogen in them. Typical “brown” ingredients might be things like shredded paper, cardboard, sawdust and pulverized woodchips.

Commercial composts generate high enough temperatures to kill all weed seeds and human and plant pathogens. Compost thermometers like this one are used to measure the compost temperature before turning it. Turning it cools the compost, aerates it and mixes microorganisms on the cooler surface back into the entire mix.
            Typical “green” ingredients can be scraps from fruits and vegetables, green parts of plants including leaves and soft stems. Brown and green ingredients must be in proper balance to achieve a ratio of carbon to nitrogen between 20:1 to 40:1.
Machines like this compost turner move down a row of compost called a windrow and mixes it by turning it over thus aerating it.
            Composting is controlled “rotting” of a mixture of these ingredients. Brown and green ingredients are finely shredded and mixed together, some water is added, a small amount of soil or fresh compost and it is turned, or aerated, when the center of the compost gets hot. If heat isn’t produced by a compost pile, then one of the necessary ingredients is missing or in short supply.
            Ideally, microorganisms from soil or fresh compost feast on moist carbon and nitrogen found in the compost ingredients, heat is produced and the entire mixture “rots” in a few months if these “rotting” microorganisms also get air. Air is provided by turning this mixture periodically or injecting air into the pile.
            Commercial composters turn large compost piles when temperatures are about 160°F toward the center of the pile. These high temperatures are needed to destroy human and plant pathogens and weed seeds.
            Small amounts of compost are more difficult to start than large piles because of our desert environment. In our desert environment, place small composters like trash cans out of the wind and protect them from the sun.
            Make sure microorganisms are in the mixture. Add a couple scoops of fresh compost or a pound of garden soil to this mixture. Add extra nitrogen such as high nitrogen fertilizer or blood meal if you think too much “brown” ingredients are in the mixture.

Summer Water Needs of Lantana, Honeysuckle and Oleander

Q. How much water does oleander, lantana and honeysuckle need during summer months? 

Lantana's are always a favorite with desert residents because of their low level of maintenance and reliability for color.

A. Whenever talking irrigation, two important considerations should be made; how much water to apply and how often to apply it. How often refers to which valve or station they are on. How much water refers to the minutes of operation of that station AND the size and number of drip emitters around each plant.
Oleander is famous for being "drought tolerant". That has nothing to do with its water use. For its footprint in the landscape, it has very high water use and it's needed in order for it to stay and look good. Otherwise, when not given enough water, even though it survives and considered drought tolerant, it can look pretty shabby.
            Deeper rooted plants like oleander should be watered less often (but with more water) than shallower rooted plants like lantana and honeysuckle. Ideally, oleander should be on a station (valve) that waters other trees and large shrubs not desert adapted. The lantana and honeysuckle would be fine on the same valve.
            Next is size. Larger plants should receive more water spread over a larger area than smaller plants. Some oleanders get quite large while others, petite are dwarf varieties, would do fine with a smaller amount.
            Larger oleanders should probably get somewhere around 15 gallons or so each time they are watered. Smaller, petite oleander probably between five and 10 gallons. If using drip irrigation, the size of the drip emitters used (gallons per hour) depends on the minutes allocated for that station.
            Lantana needs one or 2 gallons every time it’s watered. The honeysuckle, probably 3 to 4. If watered the same number of minutes, double the number or size of the emitters used on the honeysuckle.

Palm Roots Less Likely to Damage

Q. We have a large Mexican fan Palm in our courtyard which is now about 15 feet tall. About 5 to 6 feet from the tree is a “Pebblestone” plastic divider which is slightly raised. The Pebblestone representative said it is likely root problems from the palm tree. A gardening company told me the palm tree roots are not likely the problem. Which is it?
A number of people asked me about the damage from Palm roots two different types of hardscapes. Here is the skinny on this topic. This picture is not from the reader but someone else.

A. Palms are a different type of plant altogether from ornamental trees. They are monocots while most ornamental trees are dicots. The internal physiology and anatomy is very different between the two.
Palm trunks are much different from the trunks of other types of trees. It's full of these long fibers. The inside is more similar to the inside of a grass plant on steroids.
            Palm trees grow differently and have roots that are very different from ornamental trees.
Basically, palm roots grow closer to the trunk while ornamental tree roots can, if water is available, grow a distance horizontally twice their vertical height.
In Las Vegas resident asked me to intercede regarding the claim by an HOA that palm tree roots were damaging a wall that needed to be repaired. As you can see, this palm tree was growing right next to the wall and causing very little damage, if any. That's the good news. The bad news, oleanders growing in the same area were probably the culprit.
            Ornamental tree roots are larger in diameter closer to the trunk and smaller in diameter with more distance from the trunk. Palm tree roots don’t get bigger with length as like ornamental tree roots. Palm tree roots don’t increase much in diameter their entire length.
Many tree roots increase in diameter as they grow away from the trunk of the tree. Palm roots, more similar to grass roots than tree roots, do not.

          This increase in diameter of ornamental tree roots is very powerful. Heaving of sidewalks, patios, driveways, foundations, footers of walls are frequently caused by ornamental tree roots increasing in diameter if planted too close to them.
            Water and where it is applied also controls where roots grow in desert soils. If you want plant roots to grow in a specific direction and not another, apply water to the soil where you want roots to grow.
            I would not plant palms closer than 4 feet from anything that might be damaged. Apply water in the area where you want root growth. Do not apply it close to other areas where damage could result.
            Installing root barriers to add more protection to these areas is another option.