Q. Respectfully, au contraire, Mr. Morris regarding your advice to not water daily. I rescued my beautiful, full-grown pomegranate several years ago from certain death by daily watering, continuing to date. Pomegranate rescued by watering every day A. I realize your comment is not really a question but I want a chance to discuss it here. Yours is an exception. It depends on the soil, its drainage and how much water is applied. Daily watering can work under some circumstances and under these circumstances it might be the right thing to do. However, it can be dangerous to recommend it for plants particularly in our environment.             Pomegranate is a drought tolerant fruit tree compared to most other fruit trees. You can search any posting on irrigation and pomegranate and all posts from knowledgeable growers will say the same. I would hate to tell people who to irrigate pomegranate based upon one person’s success.             It is well known that shallow, frequent irrigation of woody plants, trees, shrubs and fruit trees for instance, cause the roots of plants to grow close to the surface of the soil where there is a good mixture of water and air. When plant roots grow close to the soil surface, they lose their potential tolerance to dry conditions or drought.             If the soil surface is dry, the roots of plants will grow best at depths in the soil where roots find a happy balance between water and air. Allowing the soil surface to dry discourages roots from growing there but encourages them to grow deeper in the soil.             Deep root growth provides a “buffer” during times of “drought stress” when water is not freely available. Deep root growth also provides a more stable plant during high winds or when they have a heavy fruit load.             Sometimes watering this way does not seem to “pan out” but homeowners find that watering daily with shallow irrigations is easier for them. I agree that under rare circumstances, such as very sandy soils, shallow frequent irrigations are needed. But most of landscapes should not be watered this way.

Q. We are considering planting Sissoo or Raywood Ash in our front patio which is covered with pavers. Are root problems a concern for Sissoo? I have concerns about dieback in Raywood ash because of diseases described in Northern California and Europe. Does our climate reduce the chances of disease problems?  A. To me, the choice between Sissoo or Raywood ash is like picking between an apple and an orange; they don’t do the same job in the landscape. People choose Sissoo as a fast-growing personal shade tree while the Raywood ash is not fast-growing and is not much of a personal shade tree.             Sissoo is much more likely to freeze during the winter here than Raywood ash. Because of their mature size, I don’t consider either one of them as good choices for a single-story residence in a desert climate.             I observed a few Sissoo planted at homes in Las Vegas but most of what I know about this tree’s performance after planting is from homeowners in Arizona. The major complaints are its large size, limb breakage in strong winds, heaving of sidewalks and patios by its roots, general litter from leaves and fruit and root suckering throughout the landscape.             Love it or hate it. There seems to be two opinions about this tree; people love it and others hate it. Not much in between. Homeowners who planted it in Las Vegas were surprised by its size and considered removing them after a few years.             Raywood ash is not fast-growing like Sissoo but easily handles our winter temperatures without damage. But the trunk can be damaged by intense summer sunlight. It does not produce root suckers. Raywood ash is more “ornamental” with its beautiful fall color.             Raywood ash is susceptible to a disorder, disease if you want to call it that, called Ash Decline. This disorder has been a problem in Las Vegas since the 1980s beginning with Modesto ash and later with Raywood ash. I generally don’t recommend planting ash trees susceptible to this disorder in the Las Vegas Valley.             Both trees should not be planted in a desert landscape surrounded by rock. You’re asking for trouble if you do. Instead, plant them in lawns or surrounded by other plants that require moderate to high amounts of water.

Q. Your advice has helped me get a couple of dozen figs off my relatively young trees this year.  However, the attached photos show where there were two figs a few days ago and now they are entirely eaten.  I have a net over them so I don’t think it’s birds and I cannot see bugs anywhere on the plant. Figs eaten, possibly rats A. Any animal that is an omnivore will eat figs. Birds usually peck at the fruit and it is obvious the remaining fruit was pecked apart by a bird. Birds get under netting unless it is tightly pinned to the ground. You can visualize where the bird landed on the branch and did its damage.             June beetles are flying now and they will also devour figs. They seem to prefer yellow or white figs. However, the bird netting should keep them out. These insects will be gone in a couple of weeks and your tree will continue to produce fruit. Pomegranate fruit definitely by rat             Other critters, like rats, eat them ripe or unripe and leave exactly what you are seeing; the fruit entirely gone except it’s stem still attached to the tree. Look at where the fruit was eaten and ask yourself the question, “Is the branch strong enough to support the weight of a rat?” If the answer is yes, you know rats are in the area, it looks like a rat ate it then it probably did.             Other possibilities include ground squirrels. They like to steal grapes when they are ripe and can climb trees as easily as rats. Ground squirrels will completely clean out almond trees overnight.

Q. I changed my drippers to adjustable types and have problems with them working in my backyard. I fix them either by adjusting or removing the heads. Now they work fine. This happens throughout the year but I have never seen so many fail at the same time. My front yard also uses adjustables but don’t have the same problems. I was thinking about going back to drippers for reliability.  Variable flow or adjustable drip emitter above and below.Do you like to play Whack a Mole? If you do, then you will love adjustable chip emitters. Close-up of an adjustable or variable drip emitter. I don’t hate them but I don’t like them very much and give precision drip irrigation a bad name. These are precision drip emitters that met or release water at specific volumes over a given time, usually one hour. They are color-coded by the manufacturer to indicate how many liters or gallons per hour they release. The pointed end is pushed through a hole created by a punch specifically meant for drip tubing. Do not use a nail or Phillips screw driver to make these holes. Spend four dollars and buy a punch.I call these types of emitters “precision drip emitters” to differentiate them from variable drip emitters which are extremely imprecise in their delivery of water. This is a flag-type precision drip emitter called so because of the triangular flag. The flag has a stem attached and can be removed from emitter for easy cleaning. I like them because they are so simple to use, inexpensive and easy to clean if they get plugged. A. I call “dippers”, “drip emitters” or “emitters” but I think we are talking about the same thing. I work with drip irrigation all over the world. The major reason drip systems fail is because the system is not cleaned and “flushed” regularly. Flushing and cleaning drip systems must be part of a regular maintenance schedule.             When cleaning and flushing a drip system, the primary filter or screen must be cleaned Screen filter called a “Y-filter” because it’s at an angle like the letter “Y”.This black housing can be twisted open and inside there will be a screen filter which should be washed and flushed to remove sediment and debris. There is a round On the top which can be opened for flushing the inside of the screen but it does not remove everything. thoroughly, every “dead end” must be opened and flushed with several gallons of water and emitters should be inspected for plugging when they are operating. If emitters are plugged, they must be cleaned or replaced if they cannot be cleaned. The ends of polyethylene tubing or drip tubing can be bent over and this double ring device can be slipped over the end. This double ring keeps the tubing bent over to stop water flow but also allows the end of the tubing to be opened quickly and flushed to remove debris and sediment.Some people have used electrical tape to do the same thing but these are inexpensive and fast. This is auto flush for drip irrigation. The double ring above must be open manually. This can be inserted inside the drip tubing and flushes the polyethylene pipe every time the valve comes on. I would still recommend flushing the lines manually periodically and after repairs but this helps reduce some of the labor.             A major problem is created when drip systems are repaired and but not flushed afterwards to remove dirt that enters the drip lines. If drip irrigation lines are cut and repaired, I guarantee dirt entered these drip lines. It is mandatory that the “dead ends” associated with the repair are flushed immediately afterwards.             Drip system filters are cleaned and the system flushed because dirt or sediment in the water collects inside the filters and eventually plug drip emitters. Flushing the irrigation lines removes algae and bacteria that plug emitters as well.             How frequently to clean and flush a drip system depends on the quality of the water and how much water flows through the system. Irrigation systems should be flushed more often in summer than winter.             How long it takes to flush and clean depends on the design of the system. Poorly designed drip systems take longer to flush and clean. When designing drip irrigation systems, minimize the number of “dead ends” so that flushing the system takes less time and there are fewer places that accumulate “dirt” and slime.             Most drip irrigation systems attached to municipal water are flushed once a month if the municipal water delivered is clean. Sometimes it is, sometimes it isn’t, depending on the age of the municipal system.             Even though filters must be installed as part of every drip system, small amounts of sediment pass through these filters and eventually become a problem if the system is not flushed and cleaned regularly. Failure of drip systems is gradual, not like an “on and off” switch.             Drip systems attached to well water should be flushed more often because this water is “dirtier”. How often depends on the quality of the well water which varies from well to well. Typical cleaning and flushing might vary from weekly to biweekly during the summer months.             Algae and bacteria (you might call it “slime”) grow inside every irrigation system. Algae and bacteria are not problems with most sprinkler systems but can be problems with drip emitters because the “emitter” holes are so small.             In my opinion, drip irrigation systems must be flushed and filters cleaned on a regular basis depending on the quality of the water and the gallons used. The drip emitters used should be easy to clean and inexpensive. Variable drip emitters are inaccurate in their delivery of water but are subject to the same plugging as all other drip emitters.

Q. I have a 5-year-old orange tree and this year it has produced quite a bit of fruit. Many hang at the very end of branches and some are in clusters. I’ve read somewhere to prune these fruits However, I am not sure when to do that.  Do I prune them now? A. Removing the fruit so that other fruit can become larger is a type of pruning called “thinning”. It is also done if the amount of fruit could break limbs or cause other fruit to be pushed off the tree.             Thinning or removal of fruit from the limbs of fruit trees with a focus on increasing the size of the remaining fruit is done when the fruit is still very small. Usually about the size of your thumbnail. If the fruit becomes large before it is thinned not much benefit will be passed on to the remaining fruit.             Some fruit trees are not thinned because removing fruit doesn’t seem to make much difference and increasing the size of the remaining fruit. This is the case with most nut trees, figs, pomegranates and citrus.             Most citrus is not thinned so the remaining fruit becomes large. However, if the weight of this fruit threatens breakage of the limbs, then, of course fruit is removed to eliminate that possibility. It is best to remove the fruit early but if that is not done, remove the fruit as soon as you see the threat of limb breakage.Otherwise, support the limbs so they don’t break and do some light pruning after harvest.

Q. Why does your list of recommended fruit trees have no citrus? I understand the problem with freezing during the winter but nurseries and garden centers here sell citrus. If I could provide some sort of wind block from cold winter winds and some frost protection, would lemons or oranges have a chance or are they just generally doomed?  A. Generally, I do not recommend growing citrus in the Las Vegas Valley. Is citrus grown here? Yes, it is growing successfully in many backyards. So why don’t I recommend growing citrus? Because many planted in our Valley die during freezing winter temperatures. Some don’t.             Successfully growing citrus is better than a crapshoot. The overall climate of the Las Vegas Valley is too cold during the winter to recommend citrus. However, there are protected nooks and crannies in people’s backyards that allow for citrus to be grown. These protected nooks and crannies are called microclimates.             The major limitation for citrus here is cold winter temperatures. Cold winter temperatures are made more lethal when accompanied by strong winds. Remove these two obstacles and citrus does well.             After an ideal microclimate is found, citrus must be healthy to survive our extremes of heat and cold. Amend the soil with compost at planting time. Do not apply citrus fertilizers after August 1. For long-term health of the tree, avoid surrounding it with rock and desert landscaping.             And finally, choose fruit that you want combined with tolerance to freezing temperatures in your microclimate. Tolerance to winter temperatures is best with kumquat followed by mandarin orange, Myers lemon (only Myers) and grapefruit. Least tolerant to cold are the limes, true lemons like Ponderosa or Eureka and some of the specialty oranges.             Planting citrus here is not for everyone. Proceed with caution and look at it as a fun experiment in gardening.