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Monday, January 9, 2012

Why Is My Pine Tree So Sparse?

Q. Why does my one pine tree seem so sparse and inadequate?  I purchased four Mondale pines and treat them all equally. But the one shown in the left picture looks so scrawny.  The other one shown looks healthy and appears to be robust.  Any thoughts on that? 

Aleppo pine blight
A. The usual reason for a pine tree being sparse and not full is that it is not receiving the same treatment as the others. I have to assume the picture you are painting for me with words is the same one that I am seeing and understanding.
            When you say the tree is ”sparse or inadequate” this, to me, means that there are far fewer needles along the branches of this tree compared to the branches of other trees. Pine trees generally maintain needles on their branches until the wood gets to be three to five years old and then the needles are dropped from this older wood. This older wood is needle-less except for other small branches growing from it that are less than five years old.
            The reason for thinning is that there is not enough young growth covering the entire tree so that needles are lost at a higher rate than they are being replaced. If you were to look at the growth of the youngest branches you can actually see each year’s growth for several seasons and count back several years of growth on one branch. This gives you an idea of how much growth a tree is putting on each year so that it can be compared to the other trees.
            So bottom line for “thinning” is that the tree is not growing fast enough (or putting on enough new growth). I know that this seems a bit simplified but we have to start at the simplest point if we are going to try and figure it out. Reasons for thinning include water, fertilizer, damage to the tree, or disease or insects. So let’s follow the keep it simple rule first and handle the most frequent and common reasons. Once we have eliminated these then we can move on to the more “exotic” answers.
Pine tree dieback due to shading
            By far the most common reason is differences in the amount of applied water or water available to the plant. So when you say you treat them the same it does not necessarily mean these treatments are all reaching the trees equally. But if there is inadequate water two things will happen; the tree will put on less growth and the needles will be partially brown from the tips.
            The first thing to do is to check and make sure that whatever is delivering water to the tree is not plugged. Secondly make sure that water applied to the base of the tree is not running off the surface to some other location. Just because water is applied to a tree does not mean it is getting to the roots.
            Remember that as these trees get bigger their demand for water increases. The increase is not a simple few gallons per year but rather the increase is much more dramatic because trees are three dimensional in their water use unlike a lawn. A lawn doubles in size then its water use doubles. When a tree doubles in size its need for water is probably more than double.

Pine tree thinning due to lack of water
            One tree showing signs of water stress might be an indicator that in the next few years the others may also show the same signs. What you are seeing is a snapshot in time and may not indicate what will happen in future years if all things remain the same. As a precaution, I would start to increase your water to the trees and supplement the thin tree with some water from a hose to see if there is a difference.
            The next most common reason is that the roots of the tree in the container never fully established into the surrounding soil after planting. This can be because the tree was too old for the container and the roots started circling inside the container.
            It can also be because the tree was not firmly staked at the time of planting so the root system doesn’t move. You should be able to push on the trunk and NOT see any movement of soil at the base of the trunk.

Mondale pine dieback due to unknown,
nonpathological problem
            If you see movement of soil then the tree most likely never successfully transplanted from the container into the hole. If the tree moves easily in the soil then it is difficult for them to ever get established and most likely never will if it has been five years and they haven’t.
            Trees need to be firmly staked when planted to immobilize their roots and give them a chance to get established in the amended soil surrounding the container roots. If this is the case you are better off getting rid of it and replanting.
            A third possibility can be that it was planted too deep. If planted too deep the tree can die fairly quickly in one season or linger for several years due to damage to the trunk from disease organisms.
            Pull the soil away from the trunk and see how deep the first roots are. They should be no more than perhaps half an inch from the soil surface. Sometimes soil can fall back into the hole after planting, the plant can sink in the hole (this is why I tell people not to dig the hole deep but rather wide) or mulch can be pushed up against the trunk when it is young causing a disease called “collar rot” to develop.

Pine tree damage due to weed killer ie
herbicide (dicamba)
            The next most common reason is damage to the roots or trunk. This will be far less likely than a watering problem but much easier to identify. This can be physical damage like construction, damage from chemicals like salts or weed killers, insect or diseases like collar rot.
            If it is insects or diseases it is most likely to affect a few branches rather than the entire tree unless the damage from insects or diseases occurred to the roots or trunk. If damage is to the roots or trunk then thinning may also occur and look very similar to a lack of water.
            So inspect the trunk for loose or damaged bark. This can include damage from equipment like mowers or line trimmers if it is in a lawn area or surrounded by other plants. Check and make sure the tree is firmly anchored in the soil after this number of years.

            If none of this seems to pan out lets follow the keep it simple rule for now and increase your water during the spring and summer months.
            After looking at your pictures again another reason occurred to me. That is shade. If the tree is being shaded by other plants and not receiving enough light (at least six hours a day) then these branches in the shade can drop their needles. If this is the case then some pruning to allow more light will help.

Should I wrap the Trunks of My Date Palms?

Q. I live in Pahrump and last winter we had a cold spell that turned the fronds on most of my Canary Palms brown and one of them is still recovering. How can I protect them from the cold the rest of the winter? A few neighbors have wrapped theirs where the fronds meet the trunk with burlap. Will this help?

A. There really is no magic way to do it. Many palm trees generate their new growth in the coming and future years from the terminal buds located at the tip of the trunk. The bud is usually good to about 10F for short periods of time. If cold kills the terminal bud the tree will eventually die because it cannot continue its growth without that terminal bud. Damage can also occur to the trunk from freezing temperatures so wrapping the trunk or wrapping some lights around the trunk might help if there is wind and low temperatures.
            Remember that cold damage is measured in how low the temperature gets combined with the amount of time it stays at these temperatures. Wind makes it worse. Then you have to figure the time of year as well.
            Extreme cold is usually more damaging in late fall and early spring than mid-winter. Winter damage to palms may not show up right after the cold temperatures. In some cases the extent of the damage may linger for years. Not very encouraging but I hope this helps.

My Turnips Taste Very Bitter

Q. I planted turnips from six-packs in September.  I harvested two beautiful turnips but their flavor was terrible, approaching inedible. They were very bitter. What may have happened?

A. The timing for planting sounds okay but heat will do that to turnips and many other root crops. Turnips have a higher germination threshold temperature, about 60F, and so have to go in a bit earlier in the fall than beets, parsnips or rutabagas and later in the spring. Also, a lack of water would too but if they are a good size and shape then I doubt it is a water problem.
            Another thing to note is that turnips, like rutabagas, can contain a bitterness that some people find intolerable. This is an inherited trait in people so that some people will taste the bitterness while others may not. You may be one of these people. Also, you might try boiling them first, throw the water out half way through boiling and replace it. This may help remove bitterness.
            I would switch to a different variety or grow kohlrabi instead which I find much more enjoyable and easier to grow. Make sure your soil has been prepared with plenty of compost and phosphorus prior to planting. Make sure they get adequate water and I would even mulch them with some straw after they emerge if the temperatures are still warm.

I got an update. Turnips harvested later were not bitter so sounds like they were planted a bit too early and got hit with some high temperatures.

When Should I Pick Oranges in Las Vegas?

Q. I have a tree loaded with oranges but I am not sure when to pick them. I read in the paper today about the Meyer lemon tree and you said to pick them now. Should I pick my Washington navel orange now?

A. Since this is not a commercial growing area for oranges we have to take our best guess at the time for picking. It is not the same for Myers lemon and different oranges will be ready at different times. The problem here is if you wait to pick through the winter, we may get a hard freeze and you could lose the fruit.
            Washington navel orange fruit mature at the Christmas season in California. In hot hot tropical climates the fruit may never turn orange. In cooler climates the fruit turn orange when they mature. If it is close to Christmas and the fruit is orange, harvest it. Use a shears and leave a small nib or piece of stem attached to the fruit if you plan on keeping them for any length of time. If the stem is pulled from the fruit, it leaves a fresh wound where disease organisms can enter and cause early rotting. Pulling them is okay if you are going to use them right away, otherwise cut the stem.
            By the way, if you are going to juice this particular orange then remove the peel first or it may be bitter.

When Should I Cut My Grape Vines Back?

Q. When should I cut my grape vines back?  They're on a trellis, and are 1 year old.  During the summer they spread out very well, and produced several large groups of table grapes.

A. I would wait until late February or early March to prune them. We still have some potentially difficult times to go through this winter for grapes. Cutting them early may result in a loss of bud wood and fruit production.
            When pruning you will cut back this past years growth (it will be a different color) so that only one or two buds remain. I prefer two. Also I usually prune it back so that ten or twelve buds remain if I do it early. Then just before bud swelling in the spring (like about early March) I cut then spurs back to two buds. This way if there is dieback during the winter I won't lose the fruit producing spur.

Privet Turned Brown With Cold Weather. Is it Dead?

Q. My privet hedges turned a copper brown color.  I have three in a row on one side that are really brown while the hedge on the far right still has a substantial amount of green but is starting to get spots.  Not sure what to do to save them. Pictures are attached.

A. These pictures look like possibly cold damage. It could be more than this but I want you to do this to find out. Walk over to the privets and start bending some branches just below where they were pruned. If they are still soft and supple and bend easily without breaking then it is most likely cold damage that caused leaf death.

            If they are supple and bend, don't do anything. They will leaf out again this spring as temperatures begin to warm or you may see them leaf out sooner than that.
            If they all are snapping when you bend them, then there is severe dieback. It is still possible the dieback is due to cold weather this past November. Cold temperatures are very damaging during the early winter if the plants were caught unexpectedly by sudden drops in temperature.
            There was really nothing that you could have done to prevent this. It is the luck of the draw sometimes. However, if there was severe dieback you should have healthy stems closer to the ground. I would wait until late February or March and see where the new growth comes from. I would then cut the dead growth slightly below this new growth.
            Check and make sure they were getting water this winter. Turn your station on and look for water coming out of your irrigation emitters. If there was blockage and you didn't notice, it's possible they could die back from a lack of water. My best hunch, however, is cold damage.

My Pomegranates Were Spoiled When I Harvested Them

Q. I have a single, four year old pomegranate tree in Las Vegas.  The tree produced excellent fruit the first three years.  This year the fruit was spoiled as they came off the tree.  The tree appeared normal.  Looking at the fruit, it wasn't evident if it was infested with a bug or a disease.  Would you have any suggestions on what caused it? 
A. The most likely reason would be an insect called the leaf footed plant bug. They will infest pomegranates, almonds and pistachios most frequently. Their feeding can cause small holes in the outside of the fruit or nut.
            This wound can open the fruit for infection by disease and possibly cause a nut not to develop inside the shell causing what we called blanks, or no nut, to develop. You will see these insects overwintering on your fruit trees or nearby landscape trees as well.
Adults and nymphs
            These are nefarious denizens of the worst kind and seem to have no value except to breed more of the same. I would recommend spraying your fruit and nut trees with dormant oil twice during the winter and follow this a few days later with an insecticidal soap.
            I have seen most of these adults overwintering on the stems and trunks of trees, usually in the sunlight because of the heat they can get. I hope this helps.

White Leaves on Sage Probably Cold Damage But Dont Dry It At Such a High Temperature!

Q. I have a large pot of sage growing on the protected side of my house (north) where all my citrus and other herbs have done well.  I notice that when the weather cools, the sage leaves turn a whitish color.  I collected some for sage dressing, but I didn’t bother using the white leaves, just the green ones.  Is this a natural occurrence during cold weather?  Would those leaves have been okay to use? 
            I dry the good leaves in the oven at 225 degrees for about 1 hour, leave them out in the house to get thoroughly dry for a day or so, then crush them in a coffee grinder.  Works great for my use in the kitchen, especially for sage dressing.  

A. This white discoloration is probably some damage to the leaves due to cold. You are right, don’t use them.
            However, drying at 225F is far too high. This should be done at temperatures between 95 and about 125F. There is a lot of damage done to the herbs at high temperatures, particularly above 140F.
            Our weather and climate is perfect for drying herbs without the use of extra heat. It will take longer than one hour but the quality will be much, much better. Cut the stems of those with flower buds just starting to form. Hang these bunches in the open air and not in intense sunlight for 1 week to dry.
            If this is too slow for you, use a cookie sheet and put in the oven at the lowest temperature that provides heat. Bottom line, do not use excessive heat and keep them out of intense sunlight while drying. Hope this helps.

Don't Overdue It With Ashes from Your Fireplace in the Garden

Q. I've enjoyed your articles in the LVRJ over the years. I Love my backyard garden here on Sunrise Mountain but it's been a challenge compared to growing a garden on the Island of Maui.  I would like to augment my garden soil with the wood ashes from my fireplace. Would that be good for the garden soil? 

A. If these ashes are from plants then there should be no problem incorporating some of it. Much of this has to do with the volume that you want to add. Small volumes of this distributed over a larger area will be no problem as it will be high in some nutrients. One ton of wood ash has about 15 lbs of phosphorus and 50 lbs of potassium but it is strongly alkaline which we don't need. If this ash is coming from plastics or other manufactured products then I would not use it.

Sour Tangerine May Not Be a Tangerine

Sour orange rootstock that took over a Navel Orange tree
Q. I have a dwarf tangerine in a container that gives lots of fruit but it is sour. Why?

A. Sugar content is developed over time as fruit matures. When the fruit is immature it usually has higher acidity and low sugar content. As the fruit matures the acidity drops, and sugar content climbs. Be sure to wait for full color development in the fruit and it should be at its highest sugar content.
            Tangerine is sometimes grafted onto sour orange rootstock. If the tangerine part of the plant dies, the sour orange rootstock will replace it producing beautiful fruit but very sour and it will never become sweet. If this is the case, and this happens a lot in Las Vegas due to our winter freezes, dig it out and replace it.