To stop fruit production, spray tree when flowers open

A: Mark your calendar because yours will flower within the same week, plus or minus, every year. You’ll have to spray the tree with a chemical every year to get the fruit to drop when it’s still small and prevent the messiness later. To get it to work, spray the entire canopy of the tree when as many of the flowers are open as possible.

You will find it under several different similar trade names such as Olive Stop, Fruit Eliminator, Fruit Be Gone or some similar name. What is important is the active ingredient listed on the front label in small letters. The most common active ingredient is Florel, but you might also find it listed as NAA, Fruitone, etc.

This concentrated spray is diluted with water and first sprayed when the flowers on the tree are fully open 20 to 30 percent. For best results, it is sprayed again at 80 percent of full bloom a couple of weeks later. Commercial applicators spray the tree a single time when it’s close to full bloom. It’s a good idea to include a wetting agent or surfactant before spraying to improve the spray’s coverage and penetration.

It’s important that the flowers are open and sprayed to the point where the inside is wet, and the flower starts dripping when you’re finished. The canopy of the tree is dripping with the spray when you’re done. This is called “to the point of runoff.” Spraying the open flowers above their reach is the usual problem for most homeowners because they don’t have a good way of spraying all the flowers.

The ornamental flowering plum is an actual fruit tree. Nothing wrong with the fruit. It’s naturally puckery.

Many people make jam and jelly with it when the fruit is not sprayed. I would not recommend making jam or jelly with it if it’s been sprayed.

Q: I want to replace all my chemical fertilizers with organic formulations. The problem is that I’m not finding any organic fertilizers for landscape trees and shrubs such as podocarpus and photinia. Is it possible to make my own? Please tell me what you recommend.

A: The definition of organic can be difficult. To some people organic means free from pesticides and mineral fertilizers. To others, it’s things like fish emulsion, kelp meal or bone meal guano. To others, it means strict adherence to the USDA definition of organic. In the United States, the term organic usually means it’s a listed product of OMRI (Organic Materials Review Institute) that recommends products for the USDA’s Organic Program.

There are fertilizers in bags listed as OMRI approved. I would look for the word “organic” mentioned somewhere on the bag. Technically, a product cannot mention the word organic unless it’s recommended for USDA’s organic program.

One that comes to mind is the OMRI-listed fertilizer called All Purpose manufactured by Grow More. It resembles a mineral fertilizer when you open the bag but it’s one of the organic types.

Q: What do I do with all the partially used chemical fertilizers in my garage?

A: Most mineral fertilizers can be applied as the fertilizer bag recommends. If you no longer want or need these types of fertilizers, give them to your nonorganic neighbors for application. It’s best to use them up as normal applications rather than put them out as garbage.

The mineral fertilizers considered hazardous waste usually have a weed killer that is no longer permitted to be applied by homeowners. These fertilizers should be considered hazardous waste and disposed of according to county regulations that are intended to protect our water supply. Other types of mineral fertilizers can legally be applied.

Q: I read somewhere that spreading crushed eggshells on soil is good for the garden, so I have been doing that. I also throw tea leaves and coffee grounds on the garden, which I know is good, but I was wondering about the eggshells. Are they helpful and I should continue or forget it and throw them out?

A: They do two things: Organics improve the structure and texture of the soil and add to its chemistry. Warm wet soil decomposes the smallest stuff first.

Put eggshells and tea leaves in a blender with some water before composting or adding them to the soil. Coffee grounds are already ground up so it’s not necessary to use a blender.

Any kind of organic material breaks down in the soil through the action of organisms that turn it into “black gold,” improving soil structure and slowly releasing the chemicals they contain. There is a lot of information available on the chemicals released by eggshells and coffee grounds. But get them small if you want them to be released quicker.

Q: Our backyard pool is surrounded by 14-year-old California pepper trees. This year, in particular, the fallout of leaves from the trees is excessive, exacerbated by daily winds, and is causing significant daily pool cleaning to be required. We are reluctant to remove the trees and start over with more pool-friendly plants.

A: California pepper trees are a better choice than Brazilian pepper trees. California pepper trees are fast growers reaching a height of nearly 40 feet and a comparable width. They are one of the few trees that resemble willows but are considered to be mesic in their water use. Because they are fast growers, they break easily in the wind.

Because these are evergreen trees, they drop their leaves continuously all season long in small numbers. You can discourage leaf drop through careful irrigation.

First, make sure the irrigation water applied is over a large area, wetting it 2 feet deep, under the tree. Water should be applied to an area equal to at least half the tree’s canopy size. The irrigation run time to apply enough water so that gets deep enough would be from one to two hours.

The best way to apply water to a large area under the tree is with drip tubing laid in a coil or spiral around the trunk. I think it’s better than having a lot of single drip emitters spaced under the tree and connected to the waterline with quarter-inch tubing.

The second thing to do is start watering the morning before windy weather begins. Windy weather forces the tree to use more water than normal. Don’t let the soil get too dry or leaf drop will be heavier.

How do you know when the wind is coming? Check your weather app on your phone. It makes you a better predictor of windy weather and when to start irrigating.

Q: Will a caper bush (Capparis spinosa) grow in Las Vegas? Where might I buy one? I called a local nursery and got nowhere.

A: Briny capers are the unripened flower buds from a wild spiny plant that grows in the Mediterranean region and parts of Asia. Immature flowers from these plants are dried and then put in a brine solution for preservation. Their lemony, floral hints might remind you slightly of green olives since they are added to food as a condiment.

The plants are usually started from seed, but I’m sure some entrepreneurial online nursery grows them as plants to sell. They are about 3 feet tall and wider than they are tall since the stems tend to lay down if given a lot of water. Try planting it on the eastern side of a building with soil improvement and additional water at the time of planting.

I’m no expert but if this plant grows in the dry, hot Mediterranean region, it has a good chance of surviving our desert climate as well. Think bay laurel, oleander, Italian cypress, and you’ll get an idea of the climate and soils they like.

The information I saw maintains they are good down to winter temperatures of about 20 degrees when they get older and larger. If temperatures get in the low 20s this plant suckers from its base.

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.