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Tuesday, July 28, 2015

I Can't Find a Question on Your Newsletter!

Navigating My Blog. Blogs are a little tricky. When you go to my blog from a search engine or my newsletter you'll first end up on what's called the "Landing Page". The landing page has the logo and the most recent posts that have been submitted just below the logo.

Landing page with the logo at the top and the most recent post just below it. As you scroll down the page, posts are older.

I Can't Find the Post. The landing page can only hold a handful of posts. If there have been a lot of posts recently the post you're looking for can be buried. Scroll all the way down the landing page and see if you can find it. Scroll all the way down to the bottom of the landing page by using the wheel on your mouse. If there are a lot of recent posts, recent questions can get buried as "Older Posts". You can find older posts at the bottom of the landing page.

Click on "Older Posts" and go to the next page that will have older posts in reverse chronological order.

Go to Older Posts. Left click on "Older Posts" and it will take you to the next page of the blog and older posts. You can continue to scroll down the page and click on older posts for a long time. I have over 100 of these pages of "Older Posts".

How to Submit a Question

There are two ways to submit a question to be answered on this blog. Remember, pictures are extremely helpful when submitting questions. Close-ups of the problem are great and necessary but include a second picture further away so I can see the landscape environment.

Send Me an Email. The first way to send a question is to send me an email directly at Xtremehorticulture@gmail.com

Use My Blog to Send a Question. Another way is to send it on a new link I just put on the blog.

1. You don't have to type your name where the first arrow is but I do like to personalize my answers. I never used names if I publish a post.

2. Your email address at number two will be required because you will get a response from me. If your question is unique, it will most likely get posted on my blog unless you tell me not to.

3. Where the third arrow is please ask your question with as much detail as you can provide. I get readers from all over the world so tell me where the picture is from. This helps me to answer the question. My focus is desert horticulture but I will take a stab at it if it's not.

Fill in the boxes with your name (1), email address (2) and your question (3). Mention where your question is from so I can figure in your climate in the answer. That makes a huge difference. Pictures help!

How to Search Xtremehorticulture Blog

Q. Once on the Extremehort website, is there a way to search all the previous articles with one search attempt?

A. Just to clarify for some others out there so my answer does not cause confusion, I do not have a website. I have an Internet site that is a blog. You are on it right now. Unlike some other blogs, mine is not a personal blog but an informational blog. People write questions to me and (most of the time) I respond with some sort of answer. 

Searching My Blog. There are over 1400 questions on this blog that date back to 2010. You can search all of these questions in my blog through the use of "keywords" that you can type in the search box. Type keyword or keywords where you see the arrow pointing (1). Put your cursor there, left click in it and type. When you have entered your keyword then left click on Search (2).

Here is the search box for my blog. Enter in the keyword where you see the arrow and number 1. Tell it to search by clicking on the search button where you see an arrow and number 2. 

After you type in the keyword or keywords and tell it to search, all of the posts that contain that keyword will appear. In this example below, the keyword "tomato" was entered in the search box. After it was entered, the blog was told to search by left clicking on "Search".

I entered the keyword "tomato" in the search box and told it to search by clicking on the Search button.

The search results pop up right away. This is only the first page. There are eight pages of posts (2) that you can look at. You can go to more pages by left clicking on one of the numbers at the bottom of the search (2). You can left click on the title of a post (1) and the post will appear. 

This is the search that appears after I typed in "tomato" in the search box. The first post that came up, "Tomato Plants with No Fruit, What's Happening?' can be opened by clicking on the title (1). At the bottom of the search are the number of pages of posts that were brought up. Each page will contain several posts.
Here is the post that appears when we left clicked on the title of the first post on the first page, "Tomato Plants with No Fruit. What's Happening?" After reading this post, we can make it disappear and go back to our tomato search (2) by left clicking on the "x" of its tab located at the arrow (1). We can repeat this process of going back and forth between posts and the "tomato" search by opening and closing tabs. We can close the search by left clicking on the "x" on tab 2.

We can go back and forth between posts and the search by left clicking on tabs. Clicking on the "x" closes the tab (1). Clicking on the center of the tab (2) opens the tab.
I hope this helps a little bit in searching Xtremehorticulture of the Desert.

Get Alerts When Something New Is Posted

Q. How do I find out if you have posted something new on your blog?

A.  Some people want to know when there is something new posted on my blog. There are two ways to get notices about new posts; sign up for my newsletter or subscribe to posts and comments.

Sign up For My Weekly Newsletter.  I receive somewhere between 20,000 and 30,000 visitors to my blog every month. I have a weekly "newsletter" sent to about 1500 email addresses each week. This "newsletter" tells people the titles of new posts that were made during the week. You can look at the titles and see if you want to get the answers. The newsletter is sent out through Mail Chimp

This is how to subscribe to my "newsletter". Type in your email address in the box with the arrow pointing at it and left click on "Subscribe". You will be taken to Mail Chimp and you can subscribe. I NEVER share email addresses.

You can sign up for my weekly newsletter by typing your email address where the arrow is pointing.
Sign up for Posts or Comments or Both. You can get my posts on my blog as soon as I post them by signing up for posts. People can make comments to posts. In fact, I encourage it. The purpose of this blog is to share information. 

The only way to sign up for posts or comments is if you get the app for NetVibes, My Yahoo, or have an Atom processor (cell phone).

Comments to posts are screened by me but the only time I don't allow them is when they are strictly advertising and there's no educational content. You have a company or represent one? Go ahead and post a comment and I will approve it if it adds to the body of knowledge here.

Here is how to get alerts that a post or comment has been made on my blog. You will get alerts whenever a post is made or comment to a post. Here is how to sign up for posts or comments.If you want to receive an alert when a post is made, type in your email address where the arrow (1) is pointing. If you want to receive alerts when comments are made to a post, enter your email address where the arrow (2) is pointing.Follow the directions after you enter your email address.

You can sign up for my posts on the blog or comments to a post if you subscribe. You must download or have an app for Netvibes, My Yahoo or an Atom processor on your cell phone.

Sunday, July 26, 2015

What is This Groundcover With Pretty Pink Flowers?

Q, There's this flower in the neighborhood that looks delicate but doesn't seem to be affected by the wind.  Would you know what it is?

A, Yes, this is Mexican evening primrose. Oenethera spp. It is available locally and common in desert landscapes. Used in informal landscapes. It can be invasive where there is water available.

It looks pretty but the usual question I get is how to get rid of it. It tends to look not as pretty after a couple of seasons of growth. Most weed killers will not touch it. Contain it and don't let it spread everywhere. Cut it to the ground after it finishes blooming. Proceed with caution.

Some information from New Mexico State University

Long-Winded Explanation on How to Irrigate Landscapes

Q. I read your piece in the LV Review/Journal regarding the subject.  You recommended not increasing the length of watering time when it get hotter, but increasing the number of days one waters. How much time or number of days is adequate? 

I have:  Heavenly Bamboo, Gold Spot Euonymus and Golden Euonymus, Box leaf Euonymus, Pinkie Hawthorne, Med Fan Palms, Variegated Mock Orange, Pineapple Guava and more.  I live in a newer neighborhood where our plants are 1-3 years old and the landscaper put our drips on for 10 minutes twice per day when they were installed.  I can understand this when the roots are shallow, but 3 years later I’d think that is too much. Presently, I have two drips systems and have both on for 15 minutes 3 times per week for all plants.

A. These are very difficult questions to answer for a specific person because they are site-specific. The difficulty in giving you precise watering information is because of the soil at your site and how your irrigation system was designed. Whenever you have a site that has a number of different types of plants growing in the same location, it's difficult to answer with any kind of precision. I will try to answer your email as specifically as I can and in general terms.

Distribution of water. When we water plants we fill the soil with water that surrounds their roots. The water should be distributed beneath the plant so that the area receiving water is about half of the area under the canopy of the plant. In very general terms, this means spacing drip emitters usually about 18 inches apart from most soils. If irrigation basins surround the plant, the basins must be level even if the soil is not.

In soils with a lot of clay we can space emitters much farther apart. In soils that are mostly sand, the emitters must be placed closer together. So we strike a happy medium at about 18 inches apart.
Make sure you have enough emitters for plants and make sure they are spaced far enough apart to spread the water applied to the soil more evenly and over a greater distance.

Emitters can be located from six to 18 inches from the base of the plant. So for instance a 1 gallon plant would only require one drip emitter about 6 inches away. A 5 gallon plant would require 2 to 3 emitters about 12 inches away. A 15 gallon plant might require 3 to 4 emitters about 12 to 18 inches away. A 24 inch box plant might require 6 to 8 emitters scattered 18 inches apart under the canopy. 

Basically we want the water delivered to the plant so that it spreads as evenly as possible over the roots.

How many minutes. As I said above, when we water plants we fill the soil with water that surrounds their roots. The number of minutes to run the cycle depends on how deep the roots are and how fast the soil fills with water from the emitters. 

We generally figure that lawn roots are watered 10 to 12 inches deep, most annual vegetables and annual flowers are watered to the same depth as a lawn at 10 to 12 inches deep. There are exceptions in the vegetables such as onions, garlic at 6 inches deep. Small shrubs we figure have roots 12 to 18 inches deep and need water delivered to this depth. Big trees and shrubs we figure have roots 18 to 24 inches deep and need water delivered this deep. 
Depth of root system of different plants and depth of watering based upon their size

We set the minutes on our irrigation clock after we find out how many minutes it takes to get water to these depths. The only real way to determine the number of minutes needed is to run the irrigation for a certain number of minutes and "see" how deep the water goes. We can "see" how deep the water goes after a certain number of minutes using a little trick. This is the trick: "Sharp objects pushed into wet soil are pushed in much easier than the same sharp object pushed into dry soil." So we run the cycle for, let's say, 10 minutes. We wait another 10 minutes so the water finishes draining and push along sharp object into the soil next to the drip emitters in several locations. By "feeling" the resistance it takes to push these objects into the soil gives us the approximate depth that 10 minutes of water delivered. If the irrigation is not deep enough, we increase the number of minutes until we get the depth we want. 

This sounds complicated but once we do this we seldom need to change the number of minutes on the irrigation clock. This is because irrigating plants is like filling the gas tank on a car. If we drive the car until half of the gas tank is empty, we will fill the gas tank to the brim. I am willing to bet that if we fill that gas tank at the same pump each time, it will take the same number of minutes to fill half the gas tank every single time. This is the reason we can leave the minutes unchanged when we irrigate provided we use half of the water that we put into the soil each and every time before the next irrigation.

How often? This refers to the number of days we irrigate each week or every two weeks or every month. The unit of measurement (week, two weeks, monthly) depends on the irrigation clock. For simplicity let's use weekly.
I know this looks complicated. This is the general water requirement for plants on a daily basis for different months of the year in Las Vegas Nevada.

We know that plants use more water in the summer than they do the winter. Remember we are filling a gas tank so we need to let the water in that soil get "used up" before we fill it again. In the winter, that might take a week or two. In the summer, that might take one day to several days depending on the "gas tank" or the soil reservoir that we filled. Soil reservoirs that are deep and wide (large trees and shrubs) hold more water than smaller reservoirs (lawns, annual flowers, vegetables). Large trees and shrubs require more emitters and they require more minutes to fill their "gas tank". We water the shallow rooted plants more often than the deeply rooted plants but we water shallow rooted plants with fewer minutes and fewer emitters. 
Make sure basins that collect water for plants are level when these plants are growing on slopes.

For most woody plants that are not from the desert, we let them use up about 50% of the water in their "gas tank" before we irrigate again. For desert trees and shrubs, trees and shrubs that originate from deserts, we water them less often because they can tolerate soils with less water in them for longer periods of time. 

Basically, we run the "gas tank" down to 30 or 40% before we irrigate desert plants again. The way that desert plants conserve water is by surviving longer between irrigations when there is less water. When water becomes available to them, they respond quickly with new growth. Plants that are not from the desert don't respond this same way.

What is reality? The reality is there is no perfect irrigation system. Residential or commercial landscapes with lots of different types of plants are going to "waste" water. An ideal irrigation system would irrigate desert plants separately from non-desert plants. A perfect irrigation system would irrigate trees and shrubs separately from lawns, flowerbeds and vegetable gardens. An ideal irrigation system would irrigate the South and West exposures differently from the North and East exposures. 

Probably the closest to an ideal landscape and irrigation design is to follow the mini oasis concept developed out of Arizona which has evolved into what is now more commonly called "hydrozones".
Minioasis Landscape design concept from Prof. Warren Jones at the University of Arizona featured in Sunset Magazine a number of years ago

To get to your specific question, landscapers irrigate plants twice a day, daily, to 1) flush salts from the soil, 2) keep the soil wet so that any salts in the soil are "diluted" and cause less damage, 3) prevent callbacks by customers and 4) promote establishment of the plants. Certainly after a week or two they should no longer be irrigated this way. It is at this point the landscape maintenance company or manager or homeowner should take over the irrigation system and apply an appropriate schedule.

This is the reason I encourage people to determine the number of minutes for each irrigation valve using a long screwdriver or a piece of 3/8 inch rebar ground to a point at one end and bent over for a handle. Once they determine the number of minutes needed, they should seldom have to change it. Instead, I would like to see them change the number of days they irrigate each week as the seasons change from winter, spring, summer and fall.

I know this is long-winded but I hope it answers some of your questions. I will post it on my blog as well because you are not alone concerning these questions.

Summer Tomatoes: Prune Tomatoes Back or Start New Ones from Seed

Q. All the tomatoes are harvested.  What do I do with the vines? Trim them back for fall? Pull them up and buy new in the fall?  Your suggestions please.

Comment: in the hot desert we have two seasons of tomato production; spring production until July and late summer until the late fall. Here, desert tomatoes stop producing during the summer months until temperatures dropped back down to the 90s again and produce until late in the fall, usually mid December.

A. I will try to make a short video and some pictures to describe this. If your tomatoes look healthy, I would cut them back after you have finished picking the fruit. How you cut them back will determine how they will perform for the rest of the summer and into the fall. By leaving healthy tomato plants that we like intact and pruning them back we save a lot of time trying to reestablish new transplants or starting them from seed. Transplants are difficult to find this time of year. It makes more sense to start new plants from seed directly in the garden.

Pruning tomatoes. When you cut tomato plants back, always cut them to a strong side shoot. Be careful about cutting back the tops of the plants too drastically. If the plants were very bushy or if there is still fruit on the interior of the plant, cutting them back too hard can cause sunburn to the interior stems and any fruit remaining. Sunburn to the fruit will ruin them of course and sunburn to older stems will cause a lot of problems and the plants may die in our hot summers. When you cut the tops back, make sure their is enough leaf cover to shade the interior stems and of course the fruit as well. Cutting the tomato plant back at the sides is less damaging. Always make sure any cutting tools are sharp and sanitized. Fertilize the plants right after cutting them back.
Sunburn on tomato fruits

Learn a new word: imbibition. Now is an excellent time to start tomatoes from seed directly in the garden for a fall crop. Soak the seed in water-soaked paper towels overnight before you plant them. This is called pre-germination. Pre-germination helps bypass the first obstacle in seed germination and that is keeping the seed moist. If the seed is kept moist, the first stage in germination called imbibition can occur quickly.The biggest problem in planting seed this time of year is the soil drying out quickly and preventing imbibition or killing a young emerging seedling. Pre-germinating the seed, or making sure the seed has imbibed water, gives the seed a jumpstart.

See a seed imbibition video

Plant directly in the garden. Plant pre-germinated tomato seeds 1/4 inch below the surface of the soil or lay the seed on top of the soil and cover with a 1/4 inch layer of topsoil. Soak the area with water and cover the seeded area with a very light mulch of pine shavings, finely shredded newspaper, vermiculite or peat moss. This very light surface mulch will keep the soil moist between irrigations and encourage germination without suffocating the seedlings. Shredded newspaper is probably the most problematic of the group. Soil temperatures are great for germination during the summer months if the soil is lightly shaded with a mulch. Once they have germinated and produced their first set of true leaves, you can move them to a new location and pamper them.

Will Clematis Grow in the Mojave Desert?

Q. I recently moved to Pahrump and would like to grow some vines to cover the east facing side of my home.  I am considering Clematis which the nursery says will grow in my zone but I am concerned that it is too hot here.  Will they grow? Do you have suggestions for vines other than trumpet vines?
Trumpet vine

A. Clematis will grow in Las Vegas as well as Pahrump. However, it is one of those plants that struggles in our desert soils and our desert climate. It will handle our desert climate as long as it has a good growing environment and not planted in a real hot location. It will perform best facing east or north. If on the South or West side, do not plant it close to anything that reflects heat during the summer. It will require a little bit more gardening knowledge on your part to grow this plant.

Amend the soil thoroughly where you are planting it. Dig the hole wide but only deep enough to accommodate the roots of the plant. Use a good quality compost or soil mix in the backfill surrounding the roots. Cover the soil surrounding the vine with 3 to 4 inches of wood chip mulch. Stake the plant the first season of growth. Fertilize only in the early spring with the general fertilizer. Prune the vine to accommodate whatever growth you're trying to achieve.

Water it deeply and infrequently as you would any tree or shrub which does not originate from a desert. The key to growing this plant is planting it in the right location, amending the soil properly at the time of planting and the use of wood chip mulch on top of the soil.
 Star Jasmine trellis at a front entry

Other vines to consider include American Ivy which is also called Virginia creeper, Australian Pea-Vine, Banksia Rose, Carolina Jasmine, Cat’s Claw, Coral Vine, English Ivy, Euonymus, Grape, Honeysuckle, Japanese Ivy, Star Jasmine and Chinese Wisteria.

Green Metallic June Beetle Flying Now

Q. We have a black mission fig tree and there is a large green bug that is eating the figs.  At first I thought the birds were eating the figs so I covered the tree with netting.  However, when I checked the tree today, I saw 4 or 5 large green bugs inside the netting eating the figs.  See the attached picture of one of the bugs.  What are these bugs, and how can they be controlled?  They are eating the figs right before the figs are ready to pick.  Any help would be greatly appreciated.
Green metallic June beetle

A. This can happen every single year on figs. This pest is the green metallic June beetle and they seem to love white figs more than dark figs. The immature form or larva of this beetle is the white grub we see eating the roots of plants like lantana and in compost piles feeding on decaying plant life. Here they are feasting on Kadota fig at the University Orchard when I was there. The larva feed on anything below ground soft that is living or recently dead.

Green metallic June beetle on Kadota fig

They will eat any soft fruit not just figs. They will go after ripe peaches or nectarines left on the tree if they are soft. The key is they must be soft fruit or they can't eat them. Peaches you can pick them a little early and let them soften and ripen in the kitchen. You can't do that with figs. They must be picked fully ripe so this is a problem with this fruit and this insect.

This insect emerges over a period of a two or three weeks during the summer and then it is gone. You can wait it out or protect the fruit with a barrier of some sort. This could be bird netting or paper bags but I realize this sounds like a lot of work to protect them for two or three weeks. I usually just let them have them during this time period. It is not worth spraying anything.

By the way, they love the sound of line trimmers and if you hold one up in the air they will fly a suicide mission directly into the ripping, flying fishing line. Disgusting.

What to Do about Leggy Lantana

Q. Would you have any advice for me concerning my Lantanas?  They are sure leggy while the ones I see out on the highways are very thick.  Could it be lack of fertilizer or water?  I do give them a lot of water.  Also, my friend's have half the plant's leaves green and beautiful but about a third are yellow? This heat seems to make it difficult to keep things alive. 

A. There are several things that complicate my response to you. It may or may not be simply a question of water. The factors you should consider which can cause plants to be leggy or the amount of full sun they receive, the variety of lantana planted, water and fertilizer.

The two driving factors here are sunlight and the variety. If these plants are receiving different amounts of sunlight it will cause one to be leggy over another one. If they are different varieties, one may be leggy over another. If we put lantana in a semi-shaded area and give it a lot of nitrogen fertilizer and water, it will become leggy compared to the same plants grown in full sun and receiving the same fertilizer and the same water.

When we grow plants in semi shade they will require less water and fertilizer than plants growing in full sun. They may grow fast in semi shade if fertilized with nitrogen fertilizers and given plenty of water but the distances between their leaves will be much greater, the leaves will be larger and thinner. They will also tend to lose their older leaves. Leaves attached to older parts of stems will turn yellow and fall from them.
Herbs getting leggy because of too much shade and not enough water

Plants grown in full sun tend to be more compact with shorter distances between leaves, smaller and thicker leaves and dark green if they are receiving enough nitrogen fertilizer. When nitrogen fertilizer in the soil is running low, leaf color will change to a lighter green and the older leaves will begin to yellow and may drop from the stems.

What to do? You can manage these plants with some pruning and the type of fertilizer you are applying. Plants growing in full sun should receive the most fertilizer. Plants growing in semi shade should receive half the amount of those growing in full sun.

Shift your fertilizer from a high nitrogen to a low nitrogen high phosphorus fertilizer. Fertilizers that are labeled for roses or tomatoes should be lower in nitrogen and higher in phosphorus and you could use these. 

Remove the long leggy stems with a sharp pruning shears all the way to the base leaving about 1 inch of stem remaining for regrowth. If removing these long stems are not aesthetically pleasing, select two or three of the longest ones and cut them back first. In two or three weeks when new growth is occurring start removing a few more until you get the look you want.

Why Are My Palm Fronds Brown?

Q.  I have had this palm for 10 years now.  It seems like every time I try to add additional water with a hose or bucket I lose more fronds. Every year I have to cut higher on the palm and get rid of the dead fronds. I don't cut anything with green on it.   I tried driving a metal stake down 18 inches but did not pick up any visible moisture in 3 different places.   Any ideas on how I can go about this from a more scientific method?

Readers palm tree with Aptenia
A. I did not see a whole lot wrong with your palm in the picture. It is pretty normal for the fronds to begin to brown out and start to die once they hit horizontal. In our climate it is also pretty common to have some tip burn on the leaves along the fronds, particularly as they get older and drop closer to horizontal. I would guess a palm tree that size might require 10 or 15 gallons each time you water.

Companion plant may be a problem. Looks like you've got Aptenia growing at the base of the palm. This plant is not complementary to a palm that has a deep root system. Aptenia has a very shallow root system. Trying to irrigate Aptenia and a palm at the same time does not work very well. If you are going to plant something at the base of a palm, you want to plant something that has a similar watering schedule.

Irrigation is different. To keep Aptenia alive you have to irrigate probably daily. Palms do not like that. They like to be watered more deeply and less often. You can squeak by this year but next year I would replant at the base of the Palm with something that is more deep-rooted that can give you some color. By the way, Aptenia might not be a good selection anyway at that location. The flowers are small at that distance so you don't get much impact from the color.

Pick something with larger flowers and a deeper root system. Look at woody perennials that can give you season-long color in that spot. Woody perennials that are repeat bloomers and I can handle the direct sunlight in that location would be a good choice. Roses come to mind.

Thursday, July 23, 2015

Suckers from a Removed Peach Tree Should Not Be Encouraged

Q. I had a old peach tree of about 30 years die, sadly. We cut it down and had it removed. Last year several suckers sprouted from below the ground. Different leaves so I know it is not peach. What are they?   Should I leave them alone and allow them to grow?
Sucker growth from the rootstock of ornamental plum. Notice the different color of leaves from the rootstock versus the top of the tree which is red

A. 30 year old peach tree is quite an accomplishment! They are normally very short-lived as far as fruit trees go. Peach is hit very hard by borers and starts to decline around 12 years of age or a bit older. A 20 year old tree is really getting up there in age.
When you purchase a peach tree from a nursery or commercially they are grafted (budded) onto a rootstock or a second tree that is growing in the ground. This is because the rootstock part of the tree has certain attributes that the peach tree does not. This can be some tolerance of wet soils, soils containing a higher amount of clay than normal, some resistance to soil salts, diseases and nematodes.
As far as peach goes, some even cause the top of the tree to be slightly smaller than it would if it grew on its own roots. There are a number of different rootstocks available for these purposes.

This may be a “plum” rootstock that you are seeing. It will produce fruit that you will probably not enjoy. Remove it and plant a peach variety that appeals to you.

What Is the Best Groundcover for Fruit Trees?

Q. What's the best groundcover under fruit trees?

A. It kind of depends on how much water costs. If water is expensive, a living groundcover might not be the best idea.
Farmer intercropping with sesame between fruit trees in Tajikistan
Also, living groundcovers like alfalfa or clovers don't return as much nitrogen to the plant as people think. In fact, they usually compete with the plant for water and nutrients and don't return the benefits that people think they should.
In our arid and desert West, surface mulches are usually the best option. I like to see woodchips from local arborists or tree trimmers used around the base of the trees to a depth of 4 inches or more.
I have seen some inter-cropping when fruit trees are young with things like melons planted beneath them. This way at least you can get double duty in food production from the water that's being applied.
Remember that intercropping increases the amount of care required because you are growing crops you have to tend. Fruit trees that may not require visits more than once every two or three weeks now have melons planted beneath them that require visits of 2 to 3 times per week.

So if it were me, I would use a nonliving groundcover such as woodchips from local tree trimmers.

Why Did My Desert Marigolds Die?

Why Did My Desert Marigolds Die?: Q. I have several Desert Marigolds in a sunny area of my yard. They are on a drip emitters, 2 gph, set to run every other day for 10 minu...

Viragrow Delivers!

Ornamental Pear Requires Deep Watering to Prevent Leaf Drop

Q. We are renting and we have a tree in our front yard that is not that old.  We have been noticing that the leaves are turning a brown on the ends and not sure if it's due to a watering issue, disease or pest problem.  I have enclosed pictures of the leaves and would appreciate any help so that we can correct the issue.

A. From the pictures, it looks like may be an ornamental pear tree. The leaves that I could see certain appear to be browning due to a lack of water. Ornamental pear can do so-so in rock mulch but it doesn’t prefer it.
My initial guess is the tree is not receiving enough water every time it is irrigated. What can be confusing is that we can see similar symptoms to trees that are also receiving too much water in this case I think it is not enough.
I am assuming the tree is on drip irrigation and I am also assuming it is in a rock landscape. We can increase watering by increasing the number of drip emitters surrounding the tree and making sure that these emitters are 12 to 18 inches from the trunk.
We can also increase the amount of water by increasing the number of minutes on the irrigation controller. The problem when we do this is that everything else that is watered will also get an increase in water when it may not be necessary.
Also, this will increase your water bill perhaps unnecessarily. It is best to increase the number of emitters that way only this particular tree will get the increase in water.
Another possibility (I don't want you to do this) is to increase the number of days the tree is receiving water during the week. This is frequently not a good solution to a lack of water.
Trees need to receive deep irrigations with lots of water, then arrest of a couple of days during the summer with no additional water, and then watered again deeply. You do not want to water trees daily if it is at all possible or unless they are in containers.

In the meantime, take a hose and give that tree a lot of water at its base very slowly. Do this once a week and I think you will see an improvement in the number of leaves produced and the overall quality of the tree.

Recommended Vines for a Very High Backyard Wall

Q. I'm looking for a vine to cover an extremely high backyard wall, approx. 10ft.  Backyard has southern exposure and the wall faces east.    I would prefer an evergreen.

A. I don’t like to answer questions about recommended plantss for specific applications. So I handed this question off to Andrea Meckley who loves these kinds of questions.

Bob Morris forwarded your question to me.  For an east facing wall, I suggest the following evergreen vines,
1.  Banks Rose (Rosa Banksea)-semi-evergreen
     yellow or white flowers are nice yet produce debris in spring, needs maintenance once in a while with wayward limbs and suckers
2.  Firethorn  Pyracantha (Pyracantha 'Graberi')
     red berries after spring white flowers may attract birds
3.  Star Jasmine (Trachelospermum jasminoides)
     fragrant white spring flowers
if you have a shady wall :
1.  Creeping Fig (Ficus pumilla)
     no flower, may damage stucco when you remove it, no flower
2.  Algerian Ivy (Hedera canariensis)
     VERY aggressive root system, may damage stucco when you remove it, no flower

    All plants will need support to stay on wall.  One place for more information on above plants is SNWA.com under 'plant search'.  Hope this helps with your decision.  Contact me with any other questions or comments.

Andrea Meckley, Certified Horticulturist


Cutting down Cotton or Poplar Will Produce Suckers That Need to Be Controlled

Q. Is anything that can be done about cottonwood suckering from the roots after you cut the tree down, I poured stump killer onto it only to find later little cottonwood trees sprouting up around the stump and the lawn. A local expert said to pull out the sprouts until they start to go away.

A. The basic idea of exhausting the root system by removing the suckers is correct. Nearly all of the poplars, including cottonwood, sucker from the roots when they are cut down.
The mature tree acts like an energy sink for new growth. As long as the mother tree is alive, healthy and growing, it helps suppress growth from the roots. Once the mother tree is removed, the suppression of sucker growth is also removed. Suckers begin to grow from the roots as a survival mechanism for the tree.
These suckers will not pull easily because they are coming from roots. The usual term by “know-it-alls” is to "exhaust" the energy reserves in the roots by constantly removing sucker growth.
Lawn dandelion killer containing dicamba in the ingredients
The tree "invests" stored energy into sucker growth in a last ditch attempt to survive after it is cut down. In Mother Nature, this usually works. In a home situation with a diligent homeowner, removal of these suckers slowly but surely, exhausts the energy supply in the roots until finally the entire tree, roots and all, expires.
What to do? Remove the suckers as soon as you see them. This is no easy task even for the young at heart. Chemicals can help us remove or kill new sucker growth. By spending some money and purchasing products such as Glyphosate or a dandelion killer that contains dicamba or triclopyr in the ingredients makes this job much easier.
I have been quite happy with my red Dragon flame weeder that is worked quite well
If a lawn is present, dandelion killer that will also kill clover or tough to control lawn weeds would be a better choice than Glyphosate. If this is a desert landscape with rock mulch everywhere, then Glyphosate would be a good and possibly better choice.
Another possibility is to use a propane flame weeder such as Red Dragon. It will not work in a lawn very well but in a desert landscape it works quite well to burn down sprouts rather than to kill them with chemicals.

Spraying must be done when the sprouts are still young and immature to get good kill. They have to stay on top of this sucker growth and not let it get out of hand and spray probably once a month during the growing season as soon as new growth appears. 

Summer Leaf Scorch and Leaf Drop Can Signal a Lack of Water

Q. All developing yellow leaves plus other things going on indicate some trouble is brewing. Are these problems related to watering, bugs or both or something else?
Peach is notorious for borer problems. The scorching on the edges of peach leaves is a good indicator they are not getting enough water. They also will drop their leaves if water stressed. In the case of peach, I would look for borer problems in the limbs and interrupting the flow of water.
The reason these apricot leaves were damaged could be from a while back since the surrounding leaves appear to be healthy.
Citrus leaves will turn yellow from strong sunlight and a lack of water. This does not appear to be a fertilizer problem.
A. In the pictures you sent I see some leaves of peach that have brown or scorched edges and some apricot leaves that look damaged. With the apricot, leaves that are surrounding the damaged leaves appear to be just fine. Your citrus leaves are yellowing as well.

None of this appears to be a lack of iron or fertilizer.

Most of this looks like a lack of water to the leaves. Look at the newest growth and compare it to the oldest growth. If the older leaves are damaged and the newer leaves are not, then this tells me the problem occurred earlier in the season. Healthy new growth tells me the problem has been corrected.

If leaves have turned brown all over the tree or all over one limb and the new growth doesn’t look like it’s improving, then this tells me the problem is still going on and something needs to be done. 

Water travels from roots to the tops. Reasons for a lack of water may not be because not enough water is applied. If water is not reaching the upper branches even though enough water was applied to the tree, it can be from damage to the roots, trunk or limbs.

Damage to the trunk or limbs can also interrupt the flow of water to leaves. This becomes evident during the heat of the summer when the leaves require more water.

Look for borer damage in the limbs, particularly to the peach. Borer damage usually occurs on the upper surfaces of major limbs that are exposed to bright sunlight.

Apply wood chip surface mulches to the soil surface to cool the soil, reduce weed problems and slow the loss of water from the soil. 

Skeletonizers Still a Problem on Grape Even If You Spray

Q. My grapevine has been overtaken by these worms/insects and at least 25% or more of the leaves have been eaten and/or turning brown. Are the grapes safe to eat?  I've attached some pics.  Early in the season I was spraying the vine with BT but maybe I didn't apply it often enough?  Could the netting that I put over the vines have made it easier for them to multiply like they did?  I know it made it difficult for me to get to the undersides of a lot of the leaves, but it was that or feed the birds!  I think I will forgo the netting going forward now that the grapevine is more established.

Midseason attack of grape leaves by grape leaf skeletonizer larva

A. I don’t think the netting had anything to do with skeletonizer. The only thing I can think of is that birds might not have been able to get in to get the adult moths. They will not touch the larvae as they have stinging hairs near their heads which keep birds from eating them.

There are probably five generations of these larvae in one season and they probably overlap on each other. The first one starts about April/Mayish and a new generation every 4 to 6 weeks so if you don’t spray at least three during the season you will miss a generation or two.

The Bt spray only lasts a few days and it is gone. Control = picking the right poison, applying at the right time, at the right dosage and the right coverage. You probably missed one or more of the generations.

Start spray applications in May. Apply every two months during warm weather. Read and follow the directions on the label. Use a “sticker” such as EZ Wet or equivalent, Apply to both the top and bottom of the leaves.

The grapes are safe to eat. Just make sure you wash them.The netting is more for bird control than anything else. It is wise to delay putting bird netting over the top of grape vines until you start to see the berries turning color.

I want to make sure you know information I’ve already posted on my blog previously. http://xtremehorticulture.blogspot.com/2014/09/grape-leaf-skeletonizer-attacks-again.html

Century Plant Yellowing: Water or Damage by Agave Weevil

Q. A friend of mine is having trouble with his Century plants, Agave and Cactus turning yellow.  These plants are in a rock yard with hand watering, they are 2 years old. Last year he had something chewing a cactus and eventually lost the plant. This year he has had no chewing.  I hope you can help us without pictures.

A. Two things come to mind when agave is yellowing this time of year...watering too often or agave weevil. Because this is the time that we see agave weevil damage below ground showing itself to our eyes above ground I tend to think of agave weevil. Particularly if it is century plant and this time of year.

Treatment to prevent damage by this insect has to be done earlier in the season before they really get going on damaging the roots.

I hope these links help.

Chaparral Sage a Good Choice for Desert Landscapes

White Fuzzies on Ash Growth

Q. I have a 6-8 yr. old ash that has this white powdery looking substance on the newer growth. Can you tell me what it is and how to eliminate it. 
Picture from reader of white growth on ash

A.  I have seen this kind of "growth" on several vegetables and herbs as well including peppers and basil over the years. I have sent pictures of these two a good friend of mine, a well-known horticulturist in Arizona asking him what he thought they were. I could tell he was giving me his best guess as well but I don't think he was very sure himself. 

Here is a post on something similar I made back in 2012

Although not exactly the same thing it appears to be more insect related than disease or physiological in nature. I wish I could give you a better response than just to keep your eye on it and let me know if things get worse. If things do get worse, then I would direct you towards a soil applied systemic insecticide for the tree if it is needed. That is the best I can do for you at this point.

Perhaps some are other readers might hazard a guess?

Saturday, July 18, 2015

Potatoes Need to Be Started Early in the Season

Q. I want to plant potatoes here in Vegas. Our season is timed different than others though so there aren't seed potatoes available now for a mid or late July planting. Will standard Yukon Gold, Russett, fingerlings or Sweet Potatoes from the grocery survive here? Or can you suggest where to get some suitable seed potatoes?

A. You are planting too late if you put them in the ground in July. We need to plant Irish potatoes here in late February or early March. Purchase seed potatoes early in the spring. Sweet potatoes are a hot weather crop and need to go in later when soil temperatures are warm, around the first week in late April or early May.

            Any Irish potato can be quartered and used for “seed”. Potato seed are not seeds at all but cut up potato tubers. When cutting potato tubers for seed, make sure each seed piece has at least two “eyes” or “dimples” and plenty of tuber connected to it.
Potato tuber developing on underground rhizome

Sterilize knives used for cutting and allow the cut pieces to “heal” in the refrigerator, moistened, for a few days prior to planting. Warm up seed pieces taken from the refrigerator to room temperature before planting.

I have used potatoes from the grocery stores for seed but you should realize that they are not certified disease free so diseases are more of a potential problem. Purchase organic potatoes for seed since standard potatoes may be treated with a sprout inhibitor. Sprout inhibitors are sometimes applied to keep them from sprouting in storage.
Harvesting potatoes
All of the potatoes you mentioned will grow here including Sweet Potatoes. Consider Red Pontiac and Red La Sota for red skinned potatoes as well as those you mention. Also try blue potatoes such as “Adirondack Blue” as well as fingerlings.

If you’re going to grow potatoes here, make them really special because regular old potatoes are not terribly expensive to purchase. I don’t know of a potato that will not grow here.

Stop Watering Lawns at Night

Q. I read with interest your column in the RJ on watering. Our small lawn seems to be dying in patches. We water 4 days a week for 20 minutes at 11pm.  We regularly feed with Turf Builder Plus and Ironite. What should we do?

Lawn disease of reader.

A. First of all change your watering time to 4 in the morning and finish before sunrise. Never put your lawn to bed at night, wet. You are asking for disease problems if you do.
Most warm weather lawn diseases need about 6 hours of a damp, dark warm environment to get active. After a watering cycle, wait 30 minutes and push a long piece of rebar or screwdriver into the lawn in several locations. Make sure it pushes easily to 10 to 12 inches before you meet much resistance.
If it does, then you are watering deep enough. If not, increase you watering until you can push it that deep. If deeper than this, reduce the minutes to 15 or so and repeat. Break your 20 minute cycle into three shorter cycles totaling 20 minutes and space them about 15 minutes apart. 
This helps prevent puddling and runoff. This fall, rent a core aerifier and punch holes in the lawn. Verify your lawn every three to four years; more often if your lawn gets a lot of foot traffic.
In lawns, nearly any iron product works so you don’t have to spend a lot of money on iron. Not true about other plants.