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Fertilize oleanders to help them thrive

Q: I have two pink dwarf oleanders planted in 18-inch clay pots that have very healthy-looking foliage but very few blossoms. One of my gardener friends says oleanders don’t like pots. Another says I’m watering too much. Do you have any suggestions that might get some me some blossoms?

A: We have dwarf oleanders at the Cooperative Extension Research Center in containers and they bloom just fine. Dwarf oleanders such as yours are a better selection for containers and they are most commonly either pink or salmon-colored.

You could try a couple of things. If the container is small, you might have to water more often to compensate for the small soil volume. Oleander produces flowers on new growth. Prune in the winter and not during the summer if you want flowers.

Plants in containers need to be repotted every two or three years. Small containers, every year. Large containers might make it up to five years.

Oleanders that aren’t getting enough water will look normal but have an open canopy and won’t bloom well. Oleanders are high water users and love fertilizer. They do not like to be watered daily and do their best if the soil does not dry excessively between waterings.

Use a complete fertilizer such as Peters or Miracle-Gro for flowering plants and water it into the soil about once every six to eight weeks.

Cover the soil in the container with mulch to help keep the soil moist. About 2 inches would be enough.

Q: I have been working compost into my soil and mulching the soil surface trying to improve it. Much of my compost is kind of raw and mulchlike, but I use it quickly so I have space to compost leaves and grass. Does incompletely composted material draw fertilizer components away from plants?

A: The finer the compost, the faster it will decompose in the garden. I don’t like compost that looks “mulchy” because it decomposes slowly and it can interfere with soil preparation and planting.

Compost for vegetable gardens should be screened, fine, dark brown or black, smell good and earthy. “Mulchy” composts can be used to prepare soil for planting trees and shrubs, but not for vegetables.

If compost is not completely broken down, it can draw nitrogen out of the soil. But this will depend on the carbon-to-nitrogen ratio, or the nitrogen content, of the compost.

I do not worry too much about using compost that is not totally decomposed growing vegetables but I lightly fertilize vegetables once a month. These additional nitrogen applications keep this kind of problem at bay.

Q: We have a small fig tree, about 2 years old. It has figs but we do not know how to determine when they are ripe for picking.

A: Figs are ready when the neck on the fig, the narrow part of the fruit attached to the stem, starts to bend and the fruit is no longer held upright. Figs do not ripen any more once they are picked. You get exactly what you pick, so they must be picked fully ripe.

Once bent, you must pick right away. Once they are ready, you will pick nearly daily. Birds are a big problem with tree-ripened figs.

Q: What is the best attack for those pesky, scary-looking creatures on pomegranate? We had them last year. Haven’t seen them yet this season. Is there something to keep them away?

A: Prevention should start during the winter months when they can be seen in the landscape as overwintering adults ready to lay eggs in the spring.

I have seen adults on bottlebrush and other trees and shrubs in home landscapes in Southern Nevada. I am sure they overwinter on a number of evergreen plants during the winter. Since the adults can fly, they move from plant to plant in search of food.

This means they come into your yard from neighbors during the growing season. Even if you control them once during the season, you always run the chance of having them again as long as there is food in your yard.

What do we know about leaf-footed plant bugs? They like to feed on pomegranates, almonds, pistachios, tomatoes, peppers, cucumbers, squash, corn, peaches, nectarines and I am sure some others.

They are closely related to stinkbugs and squash bugs, feed and reproduce like them and confused with them because they look similar from a distance.

They overwinter from year to year in the landscapes. It takes about 50 or 60 days to produce adults from eggs laid in the spring as new growth is produced.

They feed with a long hypodermic- needlelike mouth that is inserted into soft plant tissue like leaves and fruit. Their feeding on developing fruit can cause threads of sap to ooze from the fruit’s skin.

The bugs’ feeding causes misshapen fruit or fruits or nuts to drop off of the tree. Their feeding can also cause rot diseases to enter the fruit. The bugs are difficult to control because they hide unless they are swarming and reproducing near the fruit.

Hard or conventional pesticides such as Sevin or synthetic pyrethrins are the most effective for rapid kill. These can be found as ingredients in some common vegetable or fruit sprays in nurseries or garden centers.

These same ingredients are used commercially where leaf-footed plant bugs are a problem. These types of chemicals leave behind a residue that offers some later protection after they are applied.

The chemicals, though, present some safety concerns for homeowners. They must be used with caution in home landscapes, so make sure you read the label thoroughly if you choose to go this route.

Organic control is harder because these chemicals are short-lived and don’t leave behind much residue for later protection.

Organic methods will require you to inspect the tree and fruit more often and spray more frequently.

Soap sprays like Safers insecticidal soap will give good control if the spray lands on the insects. Oils like neem have been reported to give good control used in this way. Other oils include horticultural oils and canola oil.

Another possibility are pyrethrin sprays, which may give you good knockdown when sprayed on the insects directly. Organic sprays like Bt or Spinosad will not work on this insect.

A common misunderstanding is to think that organic sprays will not hurt anything except the enemy insect. This is not true. Organic sprays will kill many different insects, good and bad. So directing the sprays at the enemy insects is important.

It is also important to spray very early in the morning or near sundown. Spray when there is no wind and cover both the upper and lower sides of the leaves.

Do not use one spray repeatedly. Use several sprays in rotation with one another so you don’t end up with an uncontrolled population explosion of insects or boost insect immunity to a single spray.

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

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