Plant Replacements in the Fall or Spring

Q. I removed two Italian Cypress trees (harder project than I imagined, especially the stumps). When is a good time to replace them, how big of a hole should I dig, and how should I prepare it? 

A. I can imagine that was a very difficult job removing Italian cypress. Probably the easiest way to do it, yes I know it's already done, is to cut it off and rent a stump grinder and grind out the stumps. The wood grinding's mixed with soil makes a fabulous mulch.

            The best time to replant is in the fall months but the problem is plant selection. There is usually not much to pick from. The best stuff is gone and the nurseries don't want to be stuck with anything through the winter and availability of plants from wholesalers is limited to stuff that didn't sell. But you can still find things if you're willing to look around.

            An alternative to Italian cypress is the Skyrocket Juniper. It is hard to find but stays narrow and smaller. They used to be popular 30 or 40 years ago. This is not a desert adapted tree so it will require soil improvement and I would mulch it with wood mulch at the base on top of the soil. I have never seen it planted in our hot desert climate but I don't see a reason it won't work with some soil preparation, decent irrigation and wood mulch.

 http://www.monrovia.com/plant-catalog/plants/1715/skyrocket-juniper/

You should not have a problem planting in the same holes if the Italian cypress he removed was healthy.

            Dig a hole 3 to 4 times the diameter of the container that the plant comes in. If these holes already have quite a bit of organic matter in them... You can tell by the color... Then don't add

anything. But otherwise mix the soil you take from the hole 50/50 with compost. The best compost out there locally for doing this is Viragrow compost in North Las Vegas.

Viragrow compost available in North Las Vegas

Arizona Rosewood Is True Desert Native and Does Not Require Frequent Watering

Q. We have an Arizona Rosewood tree in our back yard. It is about 8 years old, is a double trunk tree with 4 inch circumferences on each trunk.  It stands about 12 feet tall and is about 12 to 15 feet across. One water line presently waters it 3 times a day for a total of 30 minutes and is about 15 inches from the trunks. It has been fertilized with Miracle Grow tree and shrub fertilizer

and has been treated for possible infestation of insects or grubs. 

     We have noticed that some of the leaves have been turning brown and falling from the tree. 

     Can you give some info on how many water lines it should have, what their locations should be and about how much water the tree should receive or what other problems we may be able to look for? 

A. This is the wrong irrigation schedule for Arizona Rosewood. This plant originates from the Sonoran Desert so it is a true desert plant. This means that it doesn't like frequent amounts of water in small amounts as you are giving it.

            Normal for it would be watering not very often in the winter but giving it large amounts when you do and the same amount but more often in the summer. Yes, this is a bit vague but the watering schedule you have for it now is for nondesert plants.

            With this type of schedule it is possible that it is getting water too often. It is also possible it is not getting enough water when you do water. Hard to say.

            The problem now is that this tree is accustomed to frequent watering with small amounts. Its roots have grown to favor this method of watering. At this age, this tree may have some difficulty adjusting to a new watering schedule.

            One thing we can conclude is that it is a watering problem; either too often or not enough when you do water. It is definitely not a problem of watering too often AND too much combined. If you have never added drip emitters around this tree it may be time to do so.

            I am GUESSING it is not getting enough water when you are watering. Increase the amount of water by adding more drip emitters. This is better than increasing the minutes. If you increase the minutes then EVERYTHING on that cycle will get more water, whether they need it or not and it will waste water.

            It is less likely, but possible, that the roots of the tree are getting water too often. This can cause the roots to rot particularly for many desert plants.

            If I were there I would go out to Home Depot or Lowes and get an inexpensive moisture meter for houseplants. Bring it home and push it into the soil in several locations around the tree. Use this for deciding if the plant is getting enough water or not. 

Inexpensive houseplant moisture meter that you can use outside as well to see if the soil is moist or dry before watering.

I posted this information sheet from Andrea Meckley previously.

Bermudagrass Lawn Change of Color May Be Drought

Q. We have lived in the same house in Las Vegas for the last 42 years and every June my lawn has the same problem. The lawn is a mix of common and hybrid Bermudagrass. First the grass turns grayish (in patches) and then it turns brown. It slowly comes back by September. I water according to local recommendations, use Scott's Turf builder 3 to 4 times a year and use Ortho Bug-B-Gone insect granules twice a year.
 

A. If this were tall fescue I might be tempted to say this is a disease problem. However, since it is a mixture of Bermudagrasses I think this is an irrigation problem. This will be particularly true if these problem areas are in the same locations every year.

Turfgrass or lawns will turn a smoky or grayish green when they are not getting enough water. This is because the leaf blade either folds in half or roles depending on the grass. This creates a different color; smoky or grayish green

            Bermudagrass in our climate doesn’t develop many insect or disease problems.

            The success of lawns in our desert climate is directly tied to the quality of an irrigation system. In technical terms we say the irrigation system should provide head to head coverage; water from a sprinkler head should be thrown far enough to reach the head to its right and it’s left. If we don’t provide this kind of uniformity in the design and installation of an irrigation system it can result in brown patches that don’t receive enough water.

A close-up of the grayish green color where the lawn is not getting enough water

            The water pressure in the sprinkler system should fall within a range recommended by the sprinkler manufacturer. If the water pressure is too high or too low it will affect the distribution of water and create browning of the lawn in the same areas year after year. Otherwise, there are sprinklers now that will lower the water pressure before the water is applied to the lawn.

Another indicator of drought or lack of water in a lawn are footprints. If you walk across grass that needs water, look behind you. If your footprints remain in the grass does not spring back quickly, the grass needs water.

            You can correct this problem in the short run by increasing the number of minutes that you apply water. This delivers more water to the dry areas. Unfortunately, it also delivers more water to the wet areas resulting in overwatering of the green areas.

            It is also a good idea to punch holes in the lawn with an aerating machine in the spring, particularly in the brown areas. This helps water to move into the soil and not run off into low spots if there are any.

            Bermudagrass is notorious for building up “thatch”. Thatch is a buildup of old grass stems and debris under the surface of the lawn but on top of the soil. Years ago this thatch was burned off of the lawn with fire. We can’t do that anymore. We must do it mechanically now.

A core aerifier for lawns pulls plugs or cores out of the lawn that are about 4 inches deep. This type of verification provides better drainage and water penetration for lawns suffering from drought

            It is important to dethatch Bermudagrass each year. This is usually done in the fall when overseeding it with a cool season grass like ryegrass to maintain a green winter lawn. If the lawn is not overseeded in the fall then thatch can be a huge problem in Bermudagrass.

D thatching machines, sometimes called vertical mowers, pull debris from a lawn which allows water to better penetrate the soil and reduces runoff.

            Making changes to the irrigation system will correct some of this problem and reduce the amount of water needed to keep the lawn green. Increasing the number of minutes you apply water during the heat of the summer should solve this problem in the short run.

            But I would combine this with lawn aerification every three or four years and dethatching every year to improve the amount of water entering the soil in the dry areas.

Water Italian Cypress Less Often to Prevent Drooping

Q. Why are the lower libs on Cypress tree drooping?

Italian cypress side branches drooping because of watering too often

A.  I think what you mean by Cypress is Italian cypress. The other tree which people might call Cypress would be the Arizona Cypress which is a totally different tree. Arizona Cypress is used a lot in drier landscapes but is prone to a lot of borer problems, die back and loss of limbs.

            Italian cypress can “droop” a lot if they are not watered more carefully. The usual reason lower limbs drooping on Italian cypress is because the tree is watered too often. Watering frequently produces succulent growth that does not have the strength to remain upright.
     Managing irrigations so that they are less often, or smaller amounts more often, should slow the growth and make this growth more erect and less “floppy”.

Tomato Plants Can Be Pruned or Not, Your Choice

Q. You mentioned it is possible to cut back tomatoes for a fall harvest in hot climates. How far back do you trim them?

A. No cutting back of tomato is necessary but sometimes it can help invigorate a plant which has become too large and stimulate more production. Tomato is a perennial plant that can continue to grow larger and larger if there are no freezing temperatures.

Tomato sucker coming from a larger stem

            Tomatoes are annuals in temperate climates that have freezing weather because of the killing low temperatures. However, cutting or trimming back tomatoes to side shoots can control the size of the plant, keep it more compact, and encourage new growth that will flower and produce fruit.

Tomato smaller size after summer pruning

            The two key questions are when to cut them back and how. Cut them back at a time when new growth is produced during cooler temperatures that allow for fruit to set from the flowers. The magic temperature that allows fruit to set is between 90 and 95F and lower. 

Tomato fruits with sunburn because of intense sunlight after pruning

            These temperatures appear in the Fall, usually toward mid to late September. Therefore, cutting them back around the end of August to the first week in September should provide some new growth over 2 to 3 weeks as temperatures cool.

            Timing is always a bit of a gamble because we don't know what the temperatures will be. We can only predict them from historical fall temperatures and experience.

Summer pruning tomato for size control

            How to cut them back is more difficult to explain. It might be easier to tell you what you shouldn't do. Don't cut tomatoes back to a single stem with no side growth immediately below the cut.

            Reduce the size by cutting 1/4 inch above side growth. New growth will come from leaf axles, i.e. where a side shoot is attached to a main stem.

Tomato growing new side shoots or suckers lower on the stem after pruning

            When you are finished cutting back a tomato plant it should look like a smaller version of the original plant with lots of side shoots still remaining. If you cut back a plant dramatically you may need to throw some shade cloth or a light colored and lightweight breathable fabric to provide to some shade and prevent sunburn to the main stems.

            After cutting back a plant, lightly fertilize the soil or give it a liquid fertilizer applied to the leaves. Liquid fertilizers applied to the leaves should be done early in the morning or late in the day this time of year. It would be ideal to apply a surface mulch to the top of the soil such as straw, animal bedding, shredded newspaper or grass clippings to preserve soil moisture.

Tomato Plants Can Be Some Are Pruned or Not, Your Choice

Q. You mentioned it is possible to cut back tomatoes for a fall harvest in hot climates. How far back do you trim them?

A. No cutting back of tomato is necessary but sometimes it can help invigorate a plant which has become too large and stimulate more production. Tomato is a perennial plant that can continue to grow larger and larger if there are no freezing temperatures.

Tomato sucker coming from a larger stem

            Tomatoes are annuals in temperate climates that have freezing weather because of the killing low temperatures. However, cutting or trimming back tomatoes to side shoots can control the size of the plant, keep it more compact, and encourage new growth that will flower and produce fruit.

Tomato smaller size after summer pruning

            The two key questions are when to cut them back and how. Cut them back at a time when new growth is produced during cooler temperatures that allow for fruit to set from the flowers. The magic temperature that allows fruit to set is between 90 and 95F and lower. 

Tomato fruits with sunburn because of intense sunlight after pruning

            These temperatures appear in the Fall, usually toward mid to late September. Therefore, cutting them back around the end of August to the first week in September should provide some new growth over 2 to 3 weeks as temperatures cool.

            Timing is always a bit of a gamble because we don't know what the temperatures will be. We can only predict them from historical fall temperatures and experience.

Summer pruning tomato for size control

            How to cut them back is more difficult to explain. It might be easier to tell you what you shouldn't do. Don't cut tomatoes back to a single stem with no side growth immediately below the cut.

            Reduce the size by cutting 1/4 inch above side growth. New growth will come from leaf axles, i.e. where a side shoot is attached to a main stem.

Tomato growing new side shoots or suckers lower on the stem after pruning

            When you are finished cutting back a tomato plant it should look like a smaller version of the original plant with lots of side shoots still remaining. If you cut back a plant dramatically you may need to throw some shade cloth or a light colored and lightweight breathable fabric to provide to some shade and prevent sunburn to the main stems.

            After cutting back a plant, lightly fertilize the soil or give it a liquid fertilizer applied to the leaves. Liquid fertilizers applied to the leaves should be done early in the morning or late in the day this time of year. It would be ideal to apply a surface mulch to the top of the soil such as straw, animal bedding, shredded newspaper or grass clippings to preserve soil moisture.

Redbud Branches Dying Might Be Verticillium Wilt

Q. I live in northern New Mexico (summer highs ~90 and winter lows as cold as -10).  I have had this tree for three years. I mulch it heavily in he fall and so far it produces beautiful flowers in the early spring.  Now this.....

A. I received both emails. At -10 you are right at the edge of USDA 6 and Western Redbud is recommended for zones 6 to 9. Verticillium wilt is possible. However, this tree is fairly young and it is not common on young trees. It is more common on older trees and less vigorous older growth or very vigorous growth due to over fertilization. Cytospora may be a problem if the tree was damaged during winter cold weather.

Regardless the treatment is the same and that is prune out damaged wood. A good idea anyway. Make sure your pruners are cleaned and sterilized with alcohol, Pine Sol or 5% bleach solution. Oil them afterwards if you use bleach.

With Verticillium wilt the pruned limb should be cut off 12 inches below any signs of wilting. If this is not possible then remove what you can and hope for the best. I am not sure on Redbud but VW can usually be identified on most trees by what is called vascular streaking in the wood where the wilting is occurring. Dead wood you wont see any streaking..it is dead. On some trees like olive the streaking is not visible.

This is a disease found in soils. You should not plant any trees susceptible to VW in that hole. That includes most trees. Ornamental grasses are okay to plant there. Also pines, firs, juniper and spruce.

http://pnwhandbooks.org/plantdisease/redbud-cercis-spp-verticillium-wilt

Apricot Disease Seldom Occurs in the Desert

Q. My apricots were doing very well as they have for the last several years.  After thinning a large crop this year, they were growing very well and appeared to be getting ready to pick when I opened the cots, I found the insides to be rotting.  I've tried to do a little research without success. 

A. This may be ripe fruit rot, sometimes called Brown fruit rot. It can happen if there is rain near the time of harvest. We get other diseases on fruit as well if there are rainy periods at different stages of fruit development.

            There is not much you can do except hope that rain does not occur at that time. Here is some information from the University of California. See if this description matches your problem.

http://ipm.ucanr.edu/PMG/r5100211.html

They recommend fungicide applications earlier in the season to present it but we get such a little chance of rain here to me it doesn't make any sense to make these applications. Just figure this year you had some losses that come along very infrequently.

Citrus Help For the Land of Ice and Snow

Q. I live in Michigan, so our experience with citrus is non-existent, and there are no experts in our area, but you come recommended as someone who might be able to give me some advice. 
I have a small potted orange tree with a few leaves that have turned light colored along the edges.  They aren’t yellow or brittle as one might expect in the case of iron deficiency, but are shiny and flexible like the rest of the leaves.

I bought the tree on a lark, never expecting it to survive, but it thrives except for these few leaves.

The plant is outside, on the east side of the house when the temperatures will stay about 40ºF.  The rest of the time (about 7 months a year) it is inside, on an east facing but brightly lit porch.  It has never been frosted.

The tree has been potted for 2 ½ years.  I have not re-potted it.  It is about 14” tall.  It was originally potted in soil that was 50% commercially prepared potting soil and 50% composted leaves.

Our water is very alkaline, so during the winter I water with black tea, made with distilled water and fertilize at about half strength with Miracle Grow.  During the summer I water with rainwater and fertilize with the rest of my plants, again using Miracle Grow, this time at recommended strength.

Have you any suggestions for me?  Any advice would be appreciated.

A. It will be fun for you to grow a citrus in Michigan. I am originally from Wisconsin so I can understand your interest in having a citrus growing in Michigan. First of all make sure the container is large enough for your tree. It will need to be fairly large.

Secondly the tree should be removed from the container every 2 to 3 years and wash some of the soil away from the roots. Cut off some of the roots near the outer edges and repot the citrus in the container using new potting soil. In two or three years the organic matter content of the soil in a container will be gone. The soil would become more compact and the roots of the tree will begin to suffocate. Water will not flow through the container as easily as before. The air spaces around the roots collapse. Root rot begins to set in and this usually causes leaves to start scorching on the edges, yellowing and falling from the tree. Repotting the tree every 2 to 3 years and trimming off some of the excess roots helps to keep the tree young and vigorous. Using new soil increases the air spaces around the roots and helps keep them healthy. When you take the tree out of the container, look at the roots. Healthy roots are creamy white. Roots that are beginning to die turn brown.

When you repot the citrus also reduce the size of the canopy or top of the tree. Look at stems that are too close together or on top of each other and remove them totally. Avoid giving the tree a "Butch haircut". You will generally thin out the branches and open the canopy. If some of the limbs are too long, cut them back so they are shorter and reshape the tree.

Leave the citrus out in the container outside as many months as you possibly can during the spring, summer and fall. They can take reduced sunlight for maybe two or three months but no longer than this. It sounds like to me you are keeping them inside too long. If you have a warm spell during the winter when it's not freezing, put it outside and let it get lots of sunlight. The tree will store this energy inside of its trunk and limbs and live off of it for a time when light level is low and inside the home. If you can put a florescent light close to it, a few inches away, leave it on for 12 to 14 hours or longer each day when it's inside. This will help a lot.

A common problem on citrus are scale insects, usually brown scale. Look for these brown bumps on leaves and stems. If you find them, use a horticultural oil and spray the leaves and stems with it about once a month and you will start to see the populations of this insect decrease. Brown scale and root rot because of watering too often or poor drainage and a lack of sunlight are the worst problems.

Insects on Fruit Easy to Control Without Pesticides. Just Clean Up!

Q. Could you tell me what these little buggars are and how to eliminate them?

A.  This is not a common pest of fruit. It is an insect that just happened to be in the area and found something it could eat, had more of its own and decided you had a place it could set up residence. 

I am not an entomologist but know enough that I could identify it if it was a common pest. It is not. At first I thought it was a sap beetle but it is not. 

Regardless, the control is the same. Pick up and dispose of all damaged fruit on fruit trees and the ground. Compost them or get rid of them. Once you get rid of their food supply (damaged fruit) they will begin to disappear. 

From the look of them they do not have the ability to damage fruit themselves (their mouths cannot chew things) they look for already damaged fruit so they can feed and multiply.