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Friday, July 29, 2011

Tree Stakes Should Be Removed After One Season Of Growth

Q. Hi Bob!
Tree trunk girdled by wire supports
after two years
I just found your editorial in the "The View" yesterday. I was wondering if you could answer a few questions about my trees in my yard. I have an African Sumac tree. I pulled out the wooden stakes thinking it would stay upright until the first wind storm came along. The landscaper put padded loops around the top of the branches and then secured the wires to three stakes around the tree. The tree started growing over the loops so I changed the position of the loops. Now, another landscaper took the wires off completely. I'm afraid that the next wind storm will blow the tree over again. The width of this tree is about 12 1/2 inches in circumference. Should I put wooden stakes back for this tree or should I wait to see if the tree can stand on its own?

My next question is, does the wires that hold down the tree stunt its growth? Someone told me that the tree needs to move around so that it can grow thicker and stronger. My tree looks so small compared to my neighbors who have the same tree and didn't use wires to keep it upright.

I would appreciate if you could answer my questions that I have been wondering about for a long time.

A.  Just a couple of quick rules about staking and tree growth.

Tree staked and the trunk
allowed to move
• When staking, the tree should be immobilized so that the roots do not move, not the trunk. The trunk should be allowed to move so that it becomes stronger but not move so much that it forces the rootball to move in the soil.

• Try not to leave stakes on planted trees for more than one growing season. This should be as much time as they should ever need if they need any staking at all.

• Allow side shoots to grow along the trunk the first couple of seasons. Only remove them when these become pencil diameter or larger.

The staking of trees is primarily to prevent the rootball from moving. If the rootball is prevented from moving inside the planting hole, the roots have a better chance of becoming established in the surrounding soil. Wires from the stakes should be low enough on the trunk to prevent the rootball from moving but not the upper part of the trunk.

Another possible way of staking
a tree with one stake
Unless you want a large tree for aesthetic value then select the smallest but healthiest tree possible for planting. These smaller trees become established more quickly and will surpass the larger plants in a couple of growing seasons.

Use organic surface mulch around the bottom of the tree to a distance of 3 to 4 feet from the trunk. This organic mulch should not be bark mulch but wood chips from trees that were removed by arborists in the valley and then chipped for disposal. The mulch should be 4 to 6 inches deep and kept at least 6 inches from the trunk for the first four growing seasons.

Allow shoots to grow from the trunks of newly planted trees for the first 3 to 4 years. Remove these shoots when they grow to be pencil diameter or larger. Remove them from the trunk leaving no stubs. Allow young shoots to grow from the trunk in new locations. These young shoots help to strengthen the trunk against wind and increase the trunk diameter more quickly. They also provide some shade on the trunk which can help prevent sunburn.

Wire supports attached to the trunk from stakes should be removed after one growing season. All plants grow in two dimensions: primary growth and secondary growth. Primary growth is growth from buds that contribute to the plants overall height and width. Secondary growth originates from inside the plant and makes the trunk and limbs larger in girth.

I hope this helps.

Tomatoes: All Vines And No Fruit

Sunburn on tomato fruit due to lack of leaf cover
Q. The 1st year that I had tomatoes, they were fantastic. I had so many tomatoes that I had a hard time giving them away, but the sun baked the plants ant the remaining tomatoes turned white from the blazing sun. As a result I made some shade for them (it was too late). The next year I put the shade over them and added Miracle Grow to them. They grew like crazy right through the roof ZERO FRUIT (someone told me that it was the Miracle Grow). This year I used a low nitrogen food something like 5-8-9, and one day the plants were wilting (I thought from the sun, So I shaded them. Oops.). They are still really blooming. Is there a time when the shade sould be applied? Talk about rocket science, man...I think I need a how to grow tomatoes instruction book that includes all the don't you do thises. Is such an animal available?

Tomatoes growing under 30% shade
A. When growing tomatoes you have to be careful about how much nitrogen that you apply or you will get all vines and no fruit for about 3 to 4 weeks until the nitrogen begins to run out and then they will start to flower and set fruit. I normally fertilize with high phosphorus and a moderate nitrogen fertilizer at the time of planting and do not fertilize again until I see flowers and fruit beginning to set. Once that happens, I then begin to fertilize lightly again and do so monthly. It is not the Miracle Gro. It is the amount of Miracle Gro that you applied. The fertilizer ratio that you selected might also have something to do with it. High nitrogen encourages leaf and stem growth. High phosphorus encourages flower, fruit, root development, seed and oil production.

Heirloom tomato grown in the desert
There are some people in town who are telling people that Miracle Gro is like crack for plants. This is entirely untrue. I have been using Miracle Grow, Rapid Gro, Peters and other similar mineral fertilizers for over 30 years and have found this to be the furthest from the truth. However, it does not substitute for good soil preparation and the use of compost, plenty of it, for soil bed preparation. Products like Miracle Gro should be used as supplements to enhance plant growth, not as a substitute for good soil preparation. My orchard manager did exactly the same thing as you did last fall with our tomatoes. He did not carefully apply fertilizers at about ¼ the amount on the fertilizer label. This was after the soil had been prepared in the spring. He applied the full amount for fall production of tomatoes. He got great tomato Vines and no fruit. This was after careful instructions by me not to do that but he thought if a little is good and more is better. All totally wrong! He learned a valuable lesson and we lost our fruit.

Next is your shade. If you are growing crops that flower and set fruit then do not exceed 30% shade. This includes tomatoes, peppers, eggplant, squash, melons, etc. If you are growing vegetables that you harvest for their leaves then you can increase the % of shade up to about 50%. Too much shade will cause plants that flower to reduce the number of flowers they produce, have leaves that are larger and more tender, and stems that are longer between the leaves they produce. In other words they tend to grow larger and “stretch” in their growth. Okra should not be grown in the shade. It loves full sun and lots of it. It will not perform well under any kind of shade cloth. I hope this helps.

There is not a good primer for growing vegetables in our climate. I am currently putting together some classes with a local nursery on vegetable, fruit growing and principles of landscape design for the desert. I will keep you in notified as they develop.

Thursday, July 28, 2011

Does Anyone Have A List Of Their Favorite Cacti For Containers?

Q. Would you please take the time to send a list of cacti that is best suited for containers? Thank you so much for your help.

A. I don’t know of any lists for container cacti. Any cacti can be containerized. The basic concerns will be the size of the cactus, how much it can tolerate low temperatures and how much sunlight it can handle. It may sound weird but some cacti require protection from high intensity sunlight and grow best with a little bit of shade.

Other cacti may come from the tropics and not handle temperatures below 45° F. The basic concerns are the larger the cactus, the larger the container needed. Look up the cactus you want to grow on the Internet making sure you have its correct Latin name. Find out where it came from. If it came from the tropics there is a good chance you will need to protect it from low winter temperatures. Find out about its exposure to light. If it is a shade loving cactus you will need to provide either shade cloth or lath to give it some relief from high light intensities.

Porous containers work best. This can be Terra Cotta or any porous material. The soil mix must drain freely. It should not be a houseplant mix and do not use our native desert soil. The soil mix should have compost or similar organics mixed with it at around 50% of the soil volume. The container must have a hole in the bottom for drainage. Do not put any course gravel or broken clay pot in the bottom of the container. Use the cactus soil mix through the entire container. When watering, water long enough so that water comes out the bottom of the container flushing any salts that might accumulate. I hope this helps get you started.

Maybe others have some favorite cacti that they may have liked growing in containers.

Pruning Peach and Nectarine

Reader's peach tree
Q. I have 2 fruit trees a peach & nectarine They have shoots growing out of the main body should I cut these off? I planted them last year.

A.  Congratulations. Your tree looks extremely healthy and dark green. Pruning is a management technique that you use to achieve a form or structure that you desire from the tree.

At the orchard we normally cut the fruit trees that knee height or about 30 inches at the time of planting. We do this to establish the major limbs coming from the trunk that will support the fruit loads in the future. We establish these structural limbs that we called primary scaffolds at around 30 inches because we want to pick the fruit as close to the ground as possible while still keeping the fruit off of the ground. This is because we do not let our peach trees or nectarines produce fruit far enough above our heads that we need a ladder.

Pruning fruit tree at knee height after planting
To do this we need about 10 feet between trees as a minimum. From your picture it looked like your plants were closer than this. I want to give you some good advice but it depends on the structure of the tree that you want to accomplish and where you want your fruit to be produced.
At this point I would not remove any major limbs from your young tree until leaf drop this winter. However, I would remove any limbs coming from the trunk up to a height of about 30 inches. These should be cut flush to the trunk with a clean and sterilized pruning shears. These aren't doing you any good and you will never need them. Fruit can potentially be produced on any wood that grew this past season. On our peaches and nectarines any of the new growth that was over 24 inches long we normally pruned back to about 18 inches but no more than this. I hope this gets you on the right track.

Gardeners Just Don't Want To Give Figs Enough Water

Q. We planted a fig tree two years ago in the Anthem/Henderson area. We’ve had few purple figs in the last two years. Unfortunately they don’t grow any bigger than inch in diameter, they’re dry/not moist and taste like like cotton.

A. Most likely the tree is not getting enough water or not watered frequently enough. Water requirement varies with the size of the tree but a tree about ten feet tall might require about 30- 45 gallons at every watering. The amount of water during each watering does not change so don’t change the number of minutes. Instead change the frequency of watering or the number of times per week you are watering.

This time of year we are watering three times a week. The tree will benefit from a four inch layer of wood mulch applied to the soil under the canopy. To deliver this amount of water if it is not on drip you will require a four inch basin constructed around the trunk about four feet in diameter. Try this first but I have not a seen a fig growing here yet that has not performed well provided it is getting enough water.

Red Flame Table Grapes Do Well In The Mojave Desert

Red flame table grapes grown by reader in Las Vegas
Q. My Red Flame grapes are terrific this year. I think some at the end of the bunches have turned into raisons from the heat. Is there a way to prevent this? When will the vine need fertilizer? By the way I used dollar store garland hanging from the grape arbor and from my fig trees and I've avoided 99% of bird problems this year, what a relief!

A. Red Flame table grapes do well here. Because of our heat we do get uneven ripening of the berries in a single bunch. When a bunch is ready to pick you may have a variation in berries from a few raisins to some berries that are still green.

You can reduce this to some extent by reducing the amount of water the vines are getting when the berries begin to turn color in the bunches, about 3 to 4 weeks before harvest.

Dwarf Coyote Bush Planted In Small Landscape Area

Probably dwarf coyote bush
planted in a small landscape area

Q. Please look at the attached image if two 'Desert Broom' or Coyote shrubs that I bought in October 2009. Note that they are very low to the ground, less than one foot high. I am trying to obtain more of them as they do well in our yard where many other shrubs fail. The original nursery doesn’t remember them and do not know what they are from the picture. Do you have any thoughts as to where I can get eight more of these. I have been to every nursery in the area without luck.

A. My first comment to you is that you will be very sorry you purchased those plants and planted them there. Unrestrained, they are going to grow 10 to 12 feet in diameter in that space were you have about 3 feet available to them and planted 2 feet apart. They do appear to be one of the dwarf coyote bush. Probably Twin Peaks. I would not leave those plants there. Twin Peaks dwarf coyote bush will reach about 2 feet tall and 10 to 12 feet wide or more. Buy some alternative plants that will fit in the spaces that you have and repeat this plant in multiple places through the yard to give your design a feeling of continuity.

Brown Spots Emerge In Fescue Lawn In Midsummer

The lawn with brown and dead spots
Q. I need your assistance. Below photo depicts the present condition of my backyard. It has patches of dry or dead grass. I don't know what caused the problem. Is there some way to revive the grass without going to the extreme of re-sodding? And what shall I do to prevent this in the future?

A. Thanks for the picture. The picture helps and it doesn’t help. It would have helped if I saw something in the picture that gave me a clue. But there is nothing in the picture that is distinctive to me. It would be interesting to know if those dead spots were in any kind of pattern in relation to your irrigation heads.

I did notice in the picture that whatever caused the damage appears to be gone. The grass around the dead areas seem to be thriving. This would tend to eliminate irrigation as a problem unless you changed your irrigation schedule. If these dead spots occur in the same spots year after year it is usually associated with irrigation. I tend to think it is either insect or disease problems from your picture.

Lawn with poor irrigation overlap
from sprinklers
Let me just point out some weaknesses in the design that might contribute to the current problem. I tend to discourage homeowners from designing a turfgrass area in other than straight lines. I know this might be somewhat boring but water from sprinkler heads is thrown in straight lines. Irregular lines or curving lines tend to cause those areas inside the curves to be under watered or the areas outside the curves, and no longer in the turfgrass, to be overwatered.

I noticed in your picture that most of the damage is closest to the non turfgrass area while the solid turf area is less damaged. Another point, those areas of the turfgrass closest to rock mulch, sidewalks or patios in full sun tend to use more water than those areas deep inside the turf area. These areas, close to bare ground or rock mulch, tend to be warmer and more prone to insect attacks than others. Insect damage that is fresh tends to cause the grass on the edge of the damaged area to pull up freely from the lawn. If the insect damage is long gone, then fresh grass will no longer pull up easily.

Summer patch disease on tall fescue
Lawn diseases can also cause patterns like this. Unless a sample is sent to a qualified plant pathologist or we have seen the disease many times before it is a shot in the dark as to which disease it might be. From your picture, it is not a disease pattern I recognize as common to all our area.

Since the problem is gone, there is probably no need to apply an insecticide or fungicide. At this point leave the dead grass alone and do not rake it up or you will open the soil surface to invasion by weeds. Around the end of September through mid October rake up the dead grass and broadcast the same seed or nearly the same seed in the dead areas and mulch the surface with top dressing and fertilizer. I hope this helps.

Young Apple Tree In Rock Mulch Dies In Midsummer

Apple tree planted in rock mulch
Q. I've attached a picture of what was once a beautiful, thriving golden delicious apple tree. Within one week this is what the tree looks like! Its a young tree as you can see, I didn't plant it myself I purchased my home last July and it had just recently been planted. I picked about 10 apples from it just 2 weeks ago. Can you tell from the picture what could have caused it to dry up and die like this, especially so fast? I planted some other fruit trees that are seemingly doing very well and want to protect them from whatever caused this to happen. Thank you for any help and/or insight you can provide.

A. Because the entire tree died from top to bottom we can be relatively certain the problem was at the very bottom of the tree, in the trunk or the roots. The most common reasons are watering too much or too little, planting the tree too deeply, and leaving mulch piled around the trunk when it is young.

First, manually run the irrigation cycle and make sure that water is getting to the tree. If that cycle is operating normally and other plants on that cycle seem to be doing fine then we can probably eliminate watering. But you must check this first since this is the easiest one to eliminate.

Next, let’s eliminate planting too deeply and problems with the rock mulch. Get something to kneel on and pull the rock mulch away from the trunk. With your fingernail or a penknife cut into the part of the trunk, just barely beneath outer bark, that was covered with mulch. Make the same cut into the trunk just above the bark or make one long cut to include both.

The color of the trunk just under the bark should be identical in color in both spots; white not brown. If the color just under the bark that was covered with mulch is brown, then the tree died from collar rot due to the mulch in contact with a young trunk. Never put mulch, whether it is wood or rock, directly against the trunk for the first four growing seasons. Keep its six inches away from the trunk until it is older.

Lastly with the mulch pulled away from the trunk and still on your knees, dig the soil away from the trunk until you find the first roots. These first roots should be no deeper than about ½ inch below the soil. If roots coming from the trunk are deeper than this and soil has been placed around the trunk and the part of the trunk covered by the soil was brown, then it died of collar rot because it was planted too deeply, a common mistake.

Always plant all trees and shrubs with no more than ½ inch of soil covering the roots and make sure the tree is staked the first growing season.

Follow up to this discussion:
Thank you for this very helpful response. I did exactly as you said and it seems to be collar rot because the (rock) mulch was planted right up to the trunk and when I checked the bark was not only brown but dried out. I've moved back the mulch on all of my other trees. Thank you again.

Monday, July 25, 2011

African Sumac Has Problems

Q. I have an African sumac in my backyard that has leaves which turn brown and fall off. I have one in my front yard that does not do that. The one in the back is close to grass which gets 5 minutes of water three times a day. The one in the front is in a rock landscape and gets a lot less water. Is this natural for them or is it getting too much water or not enough fertilizer? The backyard one is on the east side and the one in the front faces west which is very hot. The one in the back is about 15 years old and about 35 feet tall and wide. Any help would be great.

A. Sometimes they can get so dense that internal shading of the canopy will cause leaves to die and drop. These are fairly messy trees due to leaf drop and dropping of their berries. If the tree in the drier landscape is more open and the tree in the back is more dense then internal shading of the canopy can be the reason.

            Other reasons might include pest problems such as aphids which can cause the leaves to be sticky or shiny and leaf drop if there are in large numbers. If the leaves are sticky, try spraying with repeat applications of soap and water or insecticidal soaps. Aphids should disappear during hot weather but reappear again during cool weather. You may also see a lot of ant activity that are working off of the aphids sugary honeydew droppings.

            You can try to open up the canopy with some branch removal (thinning of the canopy by selective limb removal) and admit more light inside the canopy. This however will probably cause some suckering on the limbs if too many limbs are removed.  You can do some light removal of small branches now.  Remove the entire small branch.

            Another possibility could be overwatering. If the tree is watered too often it is possible to develop root rots and lead drop will occur and usually branch dieback.