Recycled Christmas trees are a gift for community

Christmas trees are a valuable organic material that can be recycled and chipped into mulch. This mulch is used in public gardens and parks across the valley to help conserve soil moisture and keep plants healthy. Recycling your tree is a gift that will keep on giving back to the community.

There are no fees to participate in this community effort; just a small amount of your time. Take your Christmas trees to one of more than 20 convenient drop sites between Dec. 26 and Jan. 15.

Before dropping off your tree, please remove all nonorganic objects such as lights, wire, tinsel, ornaments and nails. Foreign objects contaminate the mulch and damage the chipper. Flocked trees cannot be recycled.

For more information about the tree recycling program or to find the nearest drop site, call 822-7700 or visit http://www.springspreserve.org/html/about_tree.html.

Q: Where would I buy a horticulture book for the Las Vegas area?

A: There are a few books on gardening out there for our climate zone. They do not necessarily have to be for the Las Vegas area, just somewhere with a similar climate zone. These books are usually available at local bookstores. A series of gardening books by George Brookbank dealing with gardening in the Tucson, Ariz., area is quite good.

The University of Nevada Cooperative Extension’s own Linn Mills has a gardening book out as well. Other resources are fact sheets available from the Cooperative Extension office. These can be obtained by telephoning our master gardener help desk at 257-5555 or through the Internet at our Web site, http://www.unce.unr.edu/publications/.

Q: I have some lemon trees with leaves that are yellowing. I will be wrapping them in burlap for winter soon and I did not know if I should treat them first.

A: Some yellowing and leaf drop on citrus can be normal since they are evergreen and do shed their leaves gradually over time. Yellowing also can be caused by a lack of available iron in the soil. Yellowing caused by a lack of iron usually has leaf veins that remain green or light green while the leaf blade turns yellow. Overwatering also can cause leaf yellowing and leaf drop.

At this point in time I would not do much of anything unless you think the tree is being overwatered. Watering more often than about once a week at this time of year is most likely excessive. Irrigations should be long, deep and infrequent; 3 to 4 inches of wood mulch will help conserve water and keep roots moist. It would probably be a mistake to use rock mulch. Do not use any plastic under the mulch. Porous weed barriers under the mulch would be acceptable if you want to use them, but they are not necessary.

If this is Meyer’s lemon, it can handle some fairly low temperatures. If you are in a cold area and have wind problems, it is probably a good idea to wrap the tree just prior to a cold front moving into the valley. I would recommend wrapping it only during times when you think the temperature may be subfreezing and then removing the wrap as temperatures warm the next day.

Q: I have three plum trees that are two years old that appear to have fire blight. What should I do to treat them for winter? They have only twiglike branches.

A: Plums do not get fire blight. This bacterial disease of fruit trees most frequently attacks pears, Asian pears, apples and quince. I am not sure what you are seeing so it is difficult for me to give you any reasonable advice. Pictures or a sample brought to my office at the Cooperative Extension would help me identify it.

If sap is oozing from the branches or trunk, it could be from stress. In this case, I would probably not recommend anything except to paint the trunk and scaffold limbs with diluted white latex paint. You should concentrate on the south and west exposures.

Do not neglect to paint the upper surfaces of major limbs as well as those that might be exposed to direct sunlight. This will help reduce sun damage to the limbs and trunk. Sun damage may cause sap to ooze as well as encourage boring insects. If plant parts are heavily infested, then cut them out or cut out the damaged areas down to healthy wood with a sharp knife.

Q: I have two low-growing hedges of box leaf euonymus and greenspire euonymus that are about six years old. They have been very healthy and now I am seeing yellow leaves that are dropping; one of the plants has lost all of its leaves. First the leaves seem to get crispy brown edges, and then the whole leaf drops off. They are planted near a wall between a sidewalk. They are on a drip system and have done beautifully in the past. I have not fertilized these plants. What can I do to save my plants?

A: Both of these plants do well here. Since they are six years old it is most likely a cultural problem, meaning that it is most likely a man-made problem.

Of course, the most obvious thing to check is to make sure none of the drip emitters are plugged and that the plants are still receiving water. Turn on the irrigation system and walk along the sidewalk and look at each emitter to make sure it is delivering about the same amount of water. If the emitters are not exposed, you will need to expose them.

If they have not been fertilized, then they most certainly need to be fertilized. These are cold-hardy plants for our area so you could fertilize them at any time of the year. If they are in a warm microclimate of the yard and grow most of the winter, then you could fertilize them now. If they are in a cold microclimate of the yard, then don’t fertilize until about Feb. 1.

The easiest way to fertilize them would be to buy some fertilizer stakes and push them into the ground beneath each emitter. You will see a big difference in these plants if they are mulched. If the soil surface does not have mulch, I would recommend mulching them with coarse mulch 3 to 4 inches deep and then moving the emitters above the mulch so you can see them. Check them periodically to make sure they are not plugged.

Frequently, these plants are sheared with hedge shears. They are getting to be about the age where they may have a lot of woody growth and not much new growth. If this is the case, you might want to consider cutting them back and allowing them to regrow to the size of the hedge so you can begin shearing them again.

It sounds as if the plants are just suffering from neglect.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.