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Tuesday, September 23, 2014

How Do I Keep Grubs Out Of Rose Bushes

Q. How do I keep grubs out of my rose bushes soil? I have used Bayer advanced complete insect killer for soil and turf. Active ingredients are Imidacloprid 0.15%   B-Cyfluthrin 0.05%   and other ingredients  99.80%. I don’t like using poisons as there are plenty of birds here. However, my roses end up with no roots and miniature leaves and blossoms as they try to survive. I ran out of wood mulch and have been using pinecones from the golf course as a temporary mulch. Could this be the problem? I don’t want to pull up the roses and toss them. They have been beautiful in the springs and falls of past. Every pinecone I turned over had 2 or 3 grubs under it, on top. Imagine what is down in the soil. Last year just one rosebush had them. I dug out all the soil and replaced it. I have used this product twice this year and still have a zillion gross grubs. Please help!!!

A. Take a look at my blog, in particular this one posting

Look at the first comment by a reader regarding grub control.  I knew about these beneficial nematodes but this person is reporting a significant reduction in them over time.

Controlling Grubs Is a Big Topic

Q. I have just been told that I have "Grubs" here in Las Vegas, NV.  What do I do to get rid of them?
Grubs from compost
A. You have two approaches to controlling grubs; conventional pesticides or organic controls. The conventional pesticides are usually much more effective and fast in getting rid of the problem.
Organic controls are slower to work and may not give you the same kind of control you can get with conventional pesticides. I would suggest purchasing a conventional insecticide in granular form and watering and in around the base of your plants.
There are several products on the market that will give you good control. You can also use a liquid but you would applied as a drench, diluting it as the label recommends and pouring it around the base of the plant where the irrigation water is applied. You would lightly water both of these products into the soil.
Do not over water or you can push the chemical beyond the depth where the grubs are feasting. Any of the conventional pesticides that are labeled for grub control will give you good control. Because these grubs are immature forms of flying insects, they may be back in future years and you will have to re-treat.

Organic controls rely on other living organisms to give you some measure of control.

There are three posts on my blog that refer to controlling grubs. The links should take you to these posts and you can read more about them if it fits your particular circumstances.

Jul 21, 2012
Q. I have discovered over 200 huge grubs in a 15 x 24 inch container that is about 2 ft deep. I had filled this container with a bag of garden soil from a garden center and planted strawberry plants. Of course the plants all died, ...

May 18, 2014
Q. I ran across an item called Grub Guard in the catalog. It contains beneficial nematodes. Would these be the same kind of nematodes that attacked my tomatoes last year? A. These are entirely different nematodes. These are ...

Aug 14, 2014

These are the immature of one of the scarab beetles such as June beetles, metallic June beetles, dung beetles and rose chafers which we have here. Another one that attacks lawn grasses is the "white grub" or sometimes just ...

My Strawberries Produce Great Leaves. Now What?

Q. My Ozark Beauty and Ogallala strawberry plants produced a few berries when first planted and now they want to propagate. This growth is filling my raised bed to my satisfaction.  I clip them down, water and watch them grow! Please provide your most welcome and appreciated advice.

A. You will want to give each individual plant its own space to grow. Space plants no closer than 1 foot apart and remove all of runners as you see them.
You can plant them further apart and propagate your own plants from the runners but you still want them no closer than 1 foot apart. All the rest of the runners you want to remove from the plants or they will get overcrowded, shade themselves, give you very low production and make it difficult to harvest.
Strawberries growing in Las Vegas in amended desert soil demonstrating good color and good health
Strawberries growing in Las Vegas soil amended with compost but showing the beginnings of iron chlorosis
The plants that you decide to keep and spaced far enough apart will last you about three years. These are the mother plants. So at the beginning of the third year begin to propagate new plants from the runners of the mother plant with the idea that these new plants will replace the mother plants at the end of the third year.
You can keep these new plants in place by just pegging or securing the new plants in a spot by holding down the runner and baby plant in its new location. When new roots begin to form you can cut it from the mother plant at cool times of the year such as March or September.
You can move them in the fall when they are young if they are not in the right place.
There are three types of strawberries classified on the time of year they produce. Main crop strawberries produce a single crop of fruit and then turn their energies to the production of runners, roots and leaves.
Strawberries with damage from the vine weevil
In my opinion you run the highest risk of not producing fruit by using main crop strawberries in our climate. Everbearing strawberries like Ogallala and Ozark Beauty are supposed to produce all during the spring, summer and fall months but usually tend to produce their fruit mostly in the spring with a trickle the rest of the year.
Then there are the day neutral varieties like Tri-Star which are supposed to produce more consistently all through the year but usually end up producing in the spring and fall when it is cooler. So expect to see fruit most likely in the spring months and some in the fall months. The rest of the time expect to see runners and leaves.
Like most vegetables and fruit trees they need at least six hours of sunlight every day. They prefer morning and early afternoon sun. They like soils with lots of compost added to it. They like to be mulched with straw or pine shavings such as animal bedding or even shredded newspaper.
Generally speaking strawberries stop producing fruit when temperatures are hot (85 to 90° F) so main crop strawberries, kind of like tomatoes, are hit and miss in our climate. We are better off with everbearing or day neutral types which you have.
However, yours are older varieties, very hardy with well-established names but there are better varieties out there. We are very limited here in what is available for home gardens so nurseries usually stay with varieties with names that are recognized. Some people plant all three types to improve their chances of getting some fruit.
Avoid fertilizing plants with nitrogen fertilizers in the early spring. Wait for them to finish producing fruit in the early summer and then fertilize them if they need it. You can tell if they need it by looking at the leaf color and size.
Fertilizing them at the beginning of summer you will be pushing new growth at a time when they normally don't produce any fruit.

The biggest problems with strawberries is iron chlorosis or yellowing leaves, keeping the soil to moist and developing root rot, Strawberry weevils, snails, slugs, pillbugs or sow bug damage to the fruits. 

Fertilizer Injectors Are Timesavers but Can Cause Problems

Q. We have a fertilizer tank attached to our watering system.  I've had it checked and it is working, as in past years.  However, this summer most of the plants in my perennial flower garden, yellow bells, and bougainvillea are green but few blooms.  Lantanas and purple rubella are blooming well.

A. Fertilizer tanks attached to an irrigation system can be a big plus for the overall landscape quality. However there are some things you should realize about using fertilizer tanks and fertilizer injectors. 

First of all plants receiving the most water, also received the most fertilizer. When we use fertilizer injectors it is best to have them inject fertilizer several minutes after the cycle begins and shut down several minutes before the cycle turns off. This gives a better fertilizer distribution to all of the plants on that circuit and cleans the irrigation lines out of any extra fertilizer. 

Water containing fertilizer sitting in irrigation lines will frequently contribute to plugging because of algae and bacterial growth that occurs in lines that contain water laden with fertilizer. If you don't have this luxury of flushing the lines with clean water, you can flush the lines yourself once a month with freshwater by turning off the injector for a few irrigations. You might want to consider not having the fertilizer tank on all of the time but using it periodically, perhaps once or twice a month, instead.

Air release valve for drip irrigation using a ball to close the valve
Air release valve for drip irrigation using a diaphragm to close the valve
Typically, plants at the beginning of an irrigation line receive more than those at the end of an irrigation line. You can eliminate some of this problem by installing an air release valve somewhere along the irrigation line. This allows trapped air to exit the irrigation line and speeds the delivery of water and fertilizer along the line to all of the plants. Otherwise air can be pushed ahead of the water and slow the delivery of water and fertilizer along the length of the irrigation line.

The type of fertilizer you are using may impact the plants as well. Try to use general purpose fertilizers with the ratio of 3-1-2 or 4-1-2 (nitrogen-phosphorus-potassium). We usually want to apply very low levels of phosphorus if we are feeding plants continually. Phosphorus can build up in the soil and become a problem if too much is applied. If particular plants require higher amounts of phosphorus than these plants can be sprayed on their foliage with a high phosphorus fertilizer or the fertilizer can be applied at their base and watered in.

From the sound of your email, you may be applying too much nitrogen. I would tend to use your injector once or twice a month if it is on continuously now. Let me know how this works for you.

Systemic Insecticide Questionable for Fruit Trees

Q. I have a mimosa silk tree that is covered in ants.  I assume they are herding aphids infesting the leaves.  I want to use a systemic ground-soak poison.  Star Nursery has a product to be used annually.  I will use it on my shade trees (eucalyptus, California Pepper, Texas Mountain Laurel, Chitalpa) if you say a systemic treatment is appropriate.
Can I also use it on my fruit trees (peach, nectarine, apricot, fig, Pink lady apple) and grape vines?  My pomegranate trees are not as infested with leaf footed hoppers as in the past, but they are there.  The kid at Star told me to just stop using the poison a few weeks before harvest, but that makes no sense to me, with an annual-use product.

I don't plan to use a systemic in my garden.

A. The product that was recommended to you was probably this one. Here is a posting on my blog regarding its use. I am never a big fan in using any kind of systemic pesticide where there are food crops. Hope this helps.

Curling and Twisted Growth of Citrus May Be Normal When It's Hot

Q. The new growth on my citrus trees (Lemon, oranges, and grapefruit) are starting to curl up at they grow. Attached are a few pictures. They are watered every three days, 12 gals per watering.   I fed them every six weeks starting at the end of Feb with a balanced citrus fertilizer.When I had a yellowing leaf problem I gave them iron and spayed the leaves with Epsom salt.  Last feeding was Sept 1. I checked some of your past blogs but could not find anything that mentioned this kind of problem. Any thoughts or suggestions.

A. In our climate this is nothing to be concerned about. We don't have a lot of citrus here so many of the insects that might cause curling or cupping of leaves are not commonly present here.
Most likely what you are seeing is growth of citrus in response to our heat. I think the outer edges of the leaves become damaged or their growth slows compared to the rest of the leaf and new growth begins to distort.

You should not see this in new growth in the spring. In other parts of the country where citrus is more common this could be an insect related problem or an irrigation problem. In our case here and because it's happening on so many of your citrus it is most likely heat related and a temporary problem.

I Have Not Been Impressed with Ambrosia Pomegranate

Q. I am very excited as I am about to plant 4 pomegranates - Ambrosia, Purple Heart, Hotuni-zigar, and Sirenvyi.  

Ambrosia pomegranate
A. Out of your four pomegranates I only have experience with Ambrosia. It is one of the earliest pomegranates but to be honest I am not a big fan of its flavor or appearance and neither were any of the chefs that I introduced it to. It did seem to improve a little bit in flavor after sitting in the refrigerator for a couple of weeks after harvest.

Perhaps some of the other readers of this blog might be able to comment on your other selections.

Using Nitrogen Fixing Plants To Fertilize My Fruit Trees

Q. I'd like to plant a few manageable nitrogen fixing plants and go about fertilization without chemicals, if possible.  Can you recommend any?  

A. There is a misunderstanding in the general horticulture community about what nitrogen fixing plants can and can't do. Nitrogen fixing plants, those plants which can take nitrogen from the air and convert it to nitrogen that a plant can use, do not produce enough nitrogen to support other plants nutritionally that most gardeners might be comfortable with.
If you are looking for a trickle of nitrogen to your trees, then perhaps selecting the right nitrogen fixing plant might provide some benefit to your trees. But most nitrogen fixing crops or plants actually require additional applications of nitrogen to perform at its higher levels of production.
Nitrogen fixing plants, in my opinion, give the greatest benefit in what we call it green manure crop. These are plants that are grown to a certain stage of maturity and then recycled back into the soil. These plants take nitrogen from the air and also nitrogen from the soil and put it into a form that can slowly decompose.
The decomposition of nitrogen fixing plants in soils allow the nitrogen that they have fixed from the air and the soil and converted into forms that slowly release this fertilizer over time. So another words, they take nitrogen that would otherwise might be lost in the environment and give crops a better chance of utilizing it.
If you are a permaculturist or a gardener who puts more value into sustainability than the appearance or total production of their garden, then you might be able to appreciate what some of these nitrogen fixing plants can do for trees.
But if you are expecting to have a level of production and visual quality of fruit that you could buy from a grocery store or a farmers market, you will probably be disappointed. This does not mean that the fruit will not taste good or it will have a decreased level of nutrients.
In fact, the opposite might occur in some fruits but you should not expect the level of production to compete with neighbors who are growing organically or conventionally.

I have attached a link from New Mexico State University that talks a little bit about this.

Kumquat Not Producing Fruit

Q. Attached is a picture of my Kumquat tree.  I apologize for the picture as there is a lot of other shrubs around the tree making it hard to get a good picture of the tree.  It has been planted for approximately three years and is 5-6 feet tall.  The picture is facing North.  Just within the last year we have had very little fruit whereas prior to that the tree was ample with fruit.  There has been no change to the water schedule (3 days per week for 45 min. each).  The tree appears to be healthy, just no fruit.   
Readers kumquat tree
The only difference I can think of is that in previous years I covered the tree whenever the temperature was below freezing; however, this past year I only covered it when the temperature fell to the upper 20s.  I think this tree is able to withstand these types of temperatures though.   Any advice you might have would be greatly appreciated.

A. Kumquat is a very winter hardy citrus and can survive most winter temperatures here without any problems provided it is in a sheltered spot. It is considered one of the more cold tolerant of the citrus. The key question you have to ask yourself is whether it produced any flowers are not this year.

The major reasons for fruit drop are temperature and irrigation problems. If we have freezing temperatures or if the plants become water stressed from not enough water, they tend to drop fruit if it was produced or even flowers. Flower buds and fruits are much less hardy to freezing temperatures than the plant itself.

Kumquat may produce fruit all through the year but tend to produce fruit in the spring and fall months and through the winter. If it does get some winter damage, you would've seen die back. The plant will regrow to the height it was before it had damage with very few flowers. Once it reestablishes the size of had before, it will then begin to flower again more profusely and produce fruit.

 If there were some spring freezes the flower buds would be killed before anything else would show any damage. This would tend to minimize fruit production. If the plant receives a lot of fertilizer, particularly nitrogen, it may tend to put on new growth with few flowers and of course very little if any fruit.

Peach Leaves Suffer from Black Spots

Q. Can you tell me what this is on one of our peach trees?
Picture from reader.
A. I am looking at your picture now of the peach leaf. It was hard to see what the problem might be with only one picture and that picture was low resolution. 

What I saw was one leaf inside the canopy in some shade with some black spots developing on the leaf margins. I couldn't be certain but it looked like there was a yellow halo around the black spots on the margins. 

I don't know if this is typical of all the leaves or just the leaves in the shade. For me there were two possibilities; irrigation or a disease called shot hole fungus or Coryneum Blight. 

If it was over the entire canopy and it involves leaves in full sunlight then I would tend to think it was irrigation related. It usually occurs if the tree is not getting enough water at the time of an irrigation or if you waited too long between irrigations. If the tree has gotten considerably larger in the last two years than I would add any emitter or two to the irrigation of the tree. I would also mulch the surface of the soil to conserve water and reduce water stress.

If this is Coryneum blight then you would spray the tree with a copper-based fungicide such as Bordeaux mixture immediately when the leaves fall from the tree this early winter. You would follow up with the spray in the spring as the leaves are coming out and new growth is emerging but after blooming has finished.

Solar Festival Event in Las Vegas

SOLARBRATION!  A free solar festival
Local group invites the community to the third annual solar festival

LAS VEGAS, Nev. – The Conservation District of Southern Nevada invites the community to attend the third Annual Solarbration solar festival which will be held Saturday, October 11, 2014 at the University of Nevada Cooperative Extension’s Lifelong Learning Center from noon to 4 p.m. The purpose of the festival is to blend art, technology and outreach to promote renewable energy, inspire conservation, and support sustainable communities. 

The Solarbration festival will offer the community the opportunity to enjoy solar-powered art, live music, food and fun.  Plus, there will be solar demonstrations and the latest information on sustainable energy.

“We promise to deliver a fun-filled family event that will be a one-stop location for everything related to going solar,” said Jon Wardlaw, Commission Chairman of the Conservation District of Southern Nevada.  “We will have all the latest information regarding energy rebates, tax credits, solar financing, and lots of hands-on activities for all ages.”

Like last year, the event will be “bike friendly” and promises to be even more fun and activity-packed than last year. The Lifelong Learning Center is located at 8050 Paradise Road, Las Vegas, Nev. (I-215 and Windmill Lane) right near the Clark County 215 trail.  Bike clubs are encouraged to make a ride out of the event. 

Solar Village
You won’t want to miss The Solar Village where visitors will have a chance to meet over 35 exhibitors, with selected presentations on solar living, electric cars and more plus have the opportunity to get answers to questions about solar energy, and find out how they can install solar on their home or business.

Plus there will be hands-on fun activities for children.  There will be solar art projects, fun in the sun games and make-and-take solar nightlights to name a few of the many and varied activities.  And the Food Trucks and live bands will be there so the evening will be complete with great food as well.

Whether you are looking for information on solar financing, the Solar Generations rebate program, Federal rebates, energy efficient home improvements, or energy star appliances, the Solar Festival will be your one-stop resource center. The wide range of exhibitors will include solar and renewable energy companies, green home builders, sustainable home products, and hybrid and electric vehicles.

The event will be free to the public and all ages are welcome.
Proceeds will go to commission a solar powered public art project to be enjoyed as our community continues to celebrate solar energy.  For more information visit http://www.cdsn.org/events/solarbration.html or like the Solar Festival – Las Vegas page on Facebook.

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Cut Back Amaryllis When Leaves Turn Brown

Q. What do I do with my 4 foot high amaryllis plants?  How much should I cut them back?
A.Amaryllis is a perennial flowering plant that comes from an underground bulb, much like a tulip. At 4 feet tall,yours is a large one. The size may vary with a variety and light exposure. If they are not getting enough light the leaves will be very succulent. With adequate light believes should be leathery and more durable. 
            Amaryllis is a fun plant to grow in the desert provided you amend the soil with compost and cover the soil surrounding it with an organic mulch such as wood chips that decompose and continue to improve the soil.Make sure you keep it away from late afternoon sun.
You have your amaryllis in good exposure it sounds like with it in the East side with some filtered light during part of the day. Amaryllis does well with half-day sunlight. As you've already expressed I'm sure that you amended your soil with compost the time of planting and mulched the bulbs.
Sometimes the flowers need staking because they can get a little top-heavy. They will die back at the first frost. At this time feel free to cut them back to the ground. Cover the bulbs with 4 to 6 inches of wood mulch through the coldest part of the winter.
When all danger of frost has passed go ahead and uncover them and let them warm up. I would fertilize lightly once a month.
You can buy Amaryllis in many of the stores like Home Depot and Lowe's while they are in bloom. Enjoy them in your home while they are blooming and then transfer them outside and plant them in the ground or in a container.
And planting them in the correct soil are both important with this plant. If you plant them in shade you might be disappointed when they don't bloom the way they are supposed to. They need light but they should receive light during the cooler parts of the day and protected from sunlight when it is very hot. This means the Eastern or northern exposures are best as long as they avoid the late afternoon sun. Planting under trees that provide filtered light, but not dense shade, will also work.
Soil improvement is extremely important. When you are planting make sure you add at least 50% compost to a desert soil. Soil amendments decides compost should include all meal or a high phosphorus fertilizer at the time of planting and mixed with the compost/soil mixture. You might need to stake the flower stalk at the time of planting if you fear wind damage. Use a thin bamboo stake and green nursery tape.
As with any flowering plants in the garden, fertilize this plant with a good fertilizer for flowering like you might use for roses or gardenias. Fertilize them once a month lightly during their growing season.
Amaryllis can also be used as a cut flower inside the home.
More information on Amaryllis from the National Arboretum You will have to adapt this information to our climate.