Oleanders like moist soil, love fertilizer

Q: I have two pink dwarf oleanders planted in 18-inch clay pots that have healthy looking foliage but few blossoms.

One of my “expert” gardener friends says simply that “oleanders don’t like pots.” Another “expert” says that I’m watering too much.

Are either of these guys right or do you have any suggestions that might get some me some blossoms?

A: We have dwarf oleanders at the Research Center in containers and they bloom just fine. There might be a couple of things you could try. If the container is small you might have to water more often to compensate for the small soil volume.

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

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

You can try using a soil moisture meter sold for houseplants that you can buy from the nursery for about $7. Water when the dial is about half way between wet and dry, do not let it get totally dry. Next, use a fertilizer like Miracle Gro 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 3 inches would be enough. If oleanders are young or if they are pruned with a hedge shears, flowers will be delayed or produce very few.

Don’t prune with a hedge shears if possible. They should be pruned with pruning shears but not hedged or gimbaled.

Q: Will my eggplant plant continue to produce through the fall and winter?

A: They will produce all the way until later in the fall but produce fruit more slowly.

Although eggplants will keep growing and flowering, they are more productive if cut back and allowed to regrow during late summer. Cut plants to about 8 to 12 inches in early August, cutting them at a crotch and allowing them to regrow.

This will mean you need to fertilize after pruning and keep the soil moist to force them to regrow. The second crop will be ready to harvest in about six weeks after cutting back. In some parts of the country eggplants are sometimes trellised and sheared for increased yield and quality later in the season.

The ideal temperatures for eggplant will be 70 to 80 F during the day and nighttime temperatures between 65 to 70 F. Very few locations will give those exact types of temperatures. Obviously they will do well in temperatures higher and lower than this. Fruit abortion begins at about 95 F with some varieties even though the plant itself can handle heat.

As temperatures get lower than ideal in the fall, eggplant will still set fruit but fruit set is not as reliable and the development of fruit is slower. Eggplant is generally considered more sensitive to cooler temperatures than its cousins, tomatoes and peppers. Flowers will consistently set fruit down to 60 F nighttime temperatures.

Nighttime temperatures below 60 F will mean fewer fruit will be set as temperatures get lower. Eggplants begin to get chilling injury at temperatures below 50 F.

Staking may be necessary if plants get big and full of fruit. Fruit touching the ground will spoil.

Harvest fruit when they are one-third full size. Over-mature fruit will be spongy, the seeds begin to harden and the fruit surface becomes dull rather than shiny.

Fruit can be snapped off the plant but it will keep longer if it is cut at the spiny stem. Mulching plants will help to set fruit and improve fruit quality.

Q: I have a dwarf orange tree planted a little over a year ago. There have been no oranges on the tree. I have fertilized and I think I’ve been watering it correctly. The tree appears to be healthy, just no fruit. Any suggestions?

A: Dwarf orange is not much help to me. The subject of oranges is huge. I need to know what type of orange it is, whether it has produced flowers or not or if the flowers formed but failed to produce fruit.

Varieties vary from early ripening — about eight months from bloom up to 16 months from bloom.

There are three main groups: the normal fruited, without navels and with light orange-colored flesh; the navel oranges, with a distinct navel development at the end; and blood oranges, with red flesh and juice.

There are 73 varieties but U.S. production focuses on Valencia, Washington navel, Hamlin, Parson Brown, pineapple and Temple. For home gardening there are many more than these six available from nurseries.

Q: I contacted the Extension Service about my oleander. It sent me a great publication about it but my main concern is pruning. I purchased the dwarf plants two years ago in 5-gallon containers. They are doing fine but are about 4 feet high. It is my understanding the plants can be pruned. I need to know the best time to do so and how far down to go without harming them.

A: Pruning oleander is very simple, much simpler than many other plants. You can prune them any time of the year but the best time is in the winter. The incorrect way is to use hedge shears if you want flowers consistently.

You can prune them with hand pruners, preferably a type called a bypass shears. Corona makes good ones that are not expensive.

Count the number of main stems coming from the base of the plant. Identify the oldest (largest in diameter) stems. Remove one-third of these larger stems leaving 1 or 2 inches above ground. You are done.

You will do this about every two or three years. No hedge shears. It takes about 10 minutes and no mess to clean up. If there are some unusually long ones remove them from the base as well.

Having said this, the absolute best time to do this is February and March but you can do it any time.

Q: Our peach tree has sap coming out from the ground level to the top of one of the limbs. Not sure if it’s too much water, not enough water, too many bugs or what.

A: This is the time of year we start noticing borer damage in peach trees. Sap comes out from the limbs and possibly all along the trunk.

A clear indicator of borer damage will be that the bark around the sappy areas will peel off, leaving bare wood under it with clear feeding damage (looks like someone took a miniature sander to the wood with no clear pattern) and if you pull enough bark away you will see flattened, oval exit holes from the adult beetles.

You may even see some sawdust under the bark in these “sanded” areas from their feeding. Remove all loose bark all the way into good wood. You may even find a flattened, ugly larva of a borer just under the bark still feeding. Keep it for a pet if you want to.

If damage is more than 50 percent around the limb, cut it off. Do not paint with black tree wound paint.

Paint the trunk and remaining limbs with diluted white latex paint (50/50 with water) on the upper surface of all branches down to 1 inch in diameter and the trunk.

Borers like limbs and trunks exposed to the hot and intense sunlight. White paint keeps limbs and trunks several degrees cooler than brown limbs and trunks and helps to reduce damage to these parts by intense sunlight.

Make sure you fertilize in January and water appropriately to keep the canopy dense and shade the limbs and trunk as much as possible.

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.