When to Plant Pomegranate in the Fall

Q. I would like to plant a pomegranate tree this Fall but I am worried that the weather is going to be cooling down soon. Do you think I missed my opportunity for planting, and should I wait for Spring?

Young pomegranate trees vary in cold hardiness but most like to be planted with woodchips rather than rock as a mulch.

A. Just because it is getting colder doesn’t mean you can’t plant. Ideally you want a few weeks of root growth in the Fall after planting. The timing may not be optimum for root growth when soil temperatures are cold, but it will still work out. If you find a variety you like, get it in the ground.

            Temperate plant roots (like pomegranate) grow best when soil temperatures are between 60 to 75F but they still grow even when soil temperatures are as low as 45F. They just don’t grow as fast. Try to plant early enough so that there are 4 to 5 weeks of warm soil temperatures before the soil gets cold.

            How to estimate the soil temperature? The best way is to buy a soil thermometer for about $15 and measure for yourself but otherwise you can make a rough approximation. Surface mulch, rock or woodchips, conserve soil warmth in the Fall and insulate soil from heat in the Spring and Summer months.

            In my experience, using your sense of touch is accurate to within about 5 degrees F of temperatures ranging from the refrigerator (40F) to the spa (105F).

            Fall planting (early) is always superior to Spring planting (late) of winter hardy plants.

Is Xtremehorticulture Advice Transferrable to St. George?

Q. I live in the St. George Utah area and use your horticulture advice regarding many of the plants in my yard. Three small questions if I may ask?

1) Is your advice, on the broad list of subjects flower-plants-shrubs- trees, ok to follow for this area?

2) I have never raised vegetables before and would the Moapa publication be a good guide for this area for a beginner grower?

3) I have two Arizona Ash on my South West side of the yard. 15 ft apart on a drip line. One had aphids this year which I watched closely and removed them with chemical spray.  However, the lower limbs continued to have leaf curl all summer with no bugs and no real damage to the leaf other than the curl.

A1. I view your climate similar to Kingman AZ and Pahrump NV. It doesn’t get as hot as LV and it can get a bit colder. You have an excellent extension guy in Rick Hefflebower located on the way to Hurricane. By all means use my information as best you can but if you aren’t sure about something run it by Rick and get his take on it. I think your soils are better than LV and you may or may not need as much soil amendment as we do in LV. The color of your soil should tell you. Certainly if you are growing vegetables or annual flowers you ALWAYS will need to add it.

A2. I attached his pamphlet for you and my planting calendar. whenever you can get local information is usually better.  You have some excellent gardeners in Washington county. I think Dr. Wittwer has some excellent info in his Moapa Valley vegetable guide but just tailor it to your climate. I think you are colder than our 3000 ft elevation I have on my calendar. I could be wrong but that is my take on it.

A.3. I think you may be more isolated in St George regarding ash decline but that is always my concern in the LV area. I saw this ash disease active in the LV community in the late 1980s so it is coming if you don’t have it.

The use of chemicals or not is a personal choice. I don’t support one side or the other. I use chemicals when all else fails. I don’t believe in throwing out the baby with the bath water.

Probably the biggest factor is wind. If its windy then irrigate that day and throw out the one day between irrigations rule. Listen to my podcast on heat and plants and it will apply to St George I think.

 

Desert Horticulture Podcast: What To Do in the Fall

 Fall months are busy in desert residential landscapes. Learn what you should be doing this fall in your home landscape.

When to Harvest European Pear

Q. I have a ten-year-old Bartlett pear tree and the pears are kind of small, about 3 inches long. The label says they ripen in August but mine are not ripe until end of October. November. I pick them, leave them out in kitchen and they become juicy and ripe. I water the trees heavily once a week and the fruit improve. Is there any way to make tree produce larger fruit?

Comice pear growing in southern Nevada.

A. Bartlett pear has the potential here for getting the same size as in the stores with the same or better quality. It is a matter of how many fruit there are compared to the number of leaves. If there are a lot of fruit and not enough leaves to support the fruit, the fruit will be smaller. 

Harvested Bartlett pear in southern Nevada.

            For Bartlett pear you should have about 45 to 50 leaves for each piece of fruit so that they can get larger. The fruit is produced on spurs that form an average of five fruit per cluster. Remove all but one fruit per cluster when the fruit has recently set and is still very small. This may be hard to judge when the fruit is just starting out in the spring but try removing all but one of the fruit in each cluster. If you want the fruit larger, next year remove more. Do it when they are small. Don’t wait. The remaining fruit will get larger. This is called “thinning the crop” or just plain “thinning”.

            Fruit also needs water present to expand and get big when its growing. Make sure the tree gets adequate water while the fruit is enlarging. If the tree doesn’t, the fruit will not grow as much. I don’t know if your watering is often enough or not. But in midsummer I would guess the trees should be watered deeply two or three times a week. Once a week is good in the Fall when it cools off.

Bartlett pear ready for harvesting, still immature yet for fresh eating.

            Pick Bartlett pears when they are still green, but the green has changed from dark green to light green. Your label is wrong. Harvesting should be in about late September or early October, not August. If you aren’t sure, pick one and cut it open to look at the seeds. The seeds should be all brown then go ahead and pick them. Picking may last two weeks as they don’t all get ready to pick at once.

    Pick the fruit before they turn yellow because this keeps the fruit texture buttery instead of gritty. Then let them ripen in a cool place out of the sun until they are ready to eat in a few days. When you get them from the store they are sometimes green. Ripen them like that before eating them.

Controlling Whiteflies on Pomegranate

Q. This past year our pomegranate bush had a lot of whiteflies. I know they do damage to the bush and so I want to control them organically and naturally. How would you suggest doing that?

Whiteflies on this pomegranate were diagnosed to be Ash whitefly by a USDA entomologist.

A. Whiteflies are a bad insect problem for any plant. I would rank them with the “hard to control” list of insects. In small numbers they can be tolerated but their populations grow so quickly that small numbers lead to large numbers very fast. For this reason, it’s important to get them under control early, as soon as you see them, in late spring and early summer. Don’t wait.

            Damage is associated with their feeding. Their feeding supports a quick growth in their population as summer temperatures get hotter. They love the heat and so they’re not seen around much until June or July. Once you see them and it’s hot, watch out! You are behind the curve and they are way ahead of you!

            In late May begin weekly inspections of the leaf undersides for whitefly adults. The adults look like living dandruff. You probably won’t see the eggs or immature forms because they are so small, but you will see the adult females preparing to lay eggs or protecting their young so that they can build their populations as quickly as possible. Pull these leaves off when you see them infested and dispose of them or vacuum them with a Dust Buster. This practice slows their populations way down.

            Control is two-pronged. First, spray pomegranate bushes on a warm day in December and then again in January with a dormant oil. You can use the commercial brands of dormant oils and horticultural oils or you can use soybean oil, canola oil, rosemary oil or cinnamon oil. 

Horticultural oil aka dormant oil are used for fall, winter, spring and early summer insect control.

Spray all the branches after pruning, top to bottom, and spray a little extra shot at the base of each tree. This spray suffocates insects that might be hiding out during the winter months. It is the most important spray for controlling insects that will be problems in 2020.

            At the beginning of June, hang bright yellow or bright blue thick construction paper in the tree smeared with Vaseline. Whiteflies fly toward bright yellow and bright blue objects and the Vaseline causes them to get stuck. As these traps begin to fill, replace them with new ones. It might look a little funny, but light reflected from aluminum foil repels them.

            If populations are totally out of control, spray with an insecticide to get their populations back under control. As a homeowner, use pesticides when all other attempts fail. Spraying with insecticides, however, have other consequences and should be a last resort.

What are Whiteflies and What Do They Look Like?

Q. In a previous post you talked about whiteflies. 

https://xtremehorticulture.blogspot.com/2015/02/how-to-control-whiteflies-on-tomato.html

https://xtremehorticulture.blogspot.com/2015/06/the-whiteflies-are-coming-whiteflies.html

What do they look like and how do I know if my plants have them?

Whiteflies on pomegranate

A. Whiteflies are commonly found on many different vegetables during summer months, like tomatoes, squash and melons. But they are not as common to ornamental trees and shrubs. As far as ornamentals go, they can be a problem for ash trees, citrus, pomegranate, gardenia, hibiscus, iris, flowering annuals, gladiolus and some others. Whiteflies are small insects, brilliant white in color as winged adults, that suck plant juices from leaves and young stems much like aphids and leafhoppers.

            If you are observant and constantly tinkering around your plants, you will notice them during the heat of the summer swarming in the air when disturbed from plant leaves like white “dandruff”. This is an indicator to look at the undersides of leaves where you will find a massive number of unwinged young’uns sucking “juice” from the plants.

            If you are not as observant, you might notice sticky, sugary sap dropping on plant leaves from the feeding just above it. Or you might see columns of ants attracted to this sugary sap, going back and forth to their underground nest carrying this sugary food. Sometimes a black mold will grow on this sugary sap in more humid climates, just like it will with aphids. This black mold is called “sooty mold” which can cause lots of plant damage if left unchecked.

            The adults can fly while the young-uns can’t.  So that swarm of white adults you see flying are adults only and a sure sign that feeding damage is underway.

            It’s winter now so you will not see whiteflies on plants unless they are on plants in warm spots like greenhouses. They are tough to control because they are resistant to  many chemical controls. If you find them early enough, removing infested leaves might keep them in check. Repeated soap and water sprays will kill them. Winter applications of dormant oil to woody trees and shrubs in January will help suppress their numbers in the summer from overwintering adults.

Dont Dig Deep Hole for Fruit Trees

Q. I am planting a 15-gallon ‘Wonderful’ pomegranate and suspicious if the plant would benefit from a deeper hole amended with washed sand to help with drainage.

A. Unless there is a drainage problem, 99% of the time there is no benefit from digging a hole deeper. There is even less benefit when adding sand to the hole in any form and this practice is likely to make drainage worse! When drainage is a problem, the simplest method is to plant on mounds.

            The majority of small tree or la
rge shrub roots are about 18 inches deep. That’s all. But the soil they are planted in must drain water or the roots will suffocate or “drown”. To check for drainage, dig a hole to the same depth as the 15-gallon planting container. Fill the hole with water and let it drain. Fill the hole a second time and watch how fast it drains. Filling this whole a second time is very important because the first filling only measures how fast water enters the soil or its “infiltration rate”. Filling the same hole a second time, when the soil is still wet, measures true drainage or its “percolation rate”.

12 year old fruit tree removed and showing the depth of its roots. Most fruit tree roots are about 18 inches deep. So wet the roots to 18 inches on fruit trees like pomegranate.

            If the water in the hole drains overnight, its drainage is acceptable. Only very shallow rooted plants like lawns, vegetables and annual flowers are watered daily during the summer months. When watering trees and shrubs the soil should be drained for at least one day between irrigations. This gives they soil and roots a chance to “breathe” before the next irrigation.

            Take my word on this but adding sand to a planting hole, either as a layer or mixed with the existing soil, is a recipe for disaster. Adobe bricks are made from a mixture of soil, sand and organics. Keep that in mind.

 

How Long to Get Figs from New Fig Tree?

Q. We're considering planting a fig tree grove in our school garden this year. How long typically does it take for them to produce figs ready for harvest?

Main crop of figs growing on new growth.

A. Figs produce fruit very quickly after planting. You should start seeing fruit produced the year after planting in most varieties. Remember, figs produce fruit on the wood that grew last year as well as the wood actively growing.

First crop of figs (Briba crop) growing on older wood (right) while the younger crop of figs (Main crop and left) is alongside the older crop. Look at the age of the wood they are growing from.

            Figs can be very big trees if you allow them to grow. They can also be cut back to a much smaller size. You mentioned planting a grove of figs. Their planting distances apart should be the same as their maximum height. If you plant them 10 feet apart, don’t let them grow above 10 feet tall.

The main crop of figs (not the first crop) will dry up and get hard if you dont give the tree more water as it gets hotter!

            Remember that figs do great in desert climates, in desert soils, in the desert heat with low humidity. But they are heavy water users much like palm trees. Water them the same as you would any other fruit tree and don’t expect production if you don’t give them enough water. They will benefit from soil covered with woodchips simply because the woodchips keep the soil moist longer. As the main crop comes on, they may dry up. This is because they dont have enough water to fully develop!!!

 

Desert Horticulture Podcast: Desert Lawn Establishment and Maintenance

 Desert lawn establishment in the Las Vegas area is lucky (or unlucky) enough to be in the transition zone for establishing lawns; both cool season and warm season grasses can make lousy lawns. Come learn why on this episode of Desert Horticulture.