GARDENING: Cold winter temperatures will influence plant recuperation

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Learn how to prune trees, shrubs, grasses, perennials, roses and fruit trees at the Gardens at the Springs Preserve, 3701 Alta Drive, from 10 a.m. to 2 p.m. Saturday.

Many industry experts will be on hand. Included among them will be the garden's own Dr. Green Thumb, who will be available to diagnose your sick plants. Demonstrations are all ongoing so come and go as you wish. You'll see hands-on demonstrations and get professional answers to your questions.

Question: I have some Mexican Bird of Paradise and it looks like they are dead. I just planted them in September. They looked OK for a while but now the tops are sticks, the leaves are brown and falling off. What is the best stuff to give them so they will bounce back? I have some orange trumpets, Texas Sage and flowering vines. They are all in the same situation.

Answer: I would not do anything to them until about mid-February to late February. You should be aware of several things.

First of all, we had some very low temperatures during December that we have not had for several years and how cold your landscape got will be a consideration in figuring out what to do. For instance, some places in the valley got down into the low twenties while others did not get that low. I do not know how cold your place got to make any judgments.

Secondly, there are three plants we call Bird of Paradise; red Mexican Bird of Paradise, Yellow Mexican Bird of Paradise and the African Bird of Paradise. Both the red Mexican and the African will not take any freezing temperatures. The yellow bird will.

Thirdly is your landscape microclimate. If these plants were in a location with lots of wind and not protected they will be more damaged than if they were in a protected location such as out of the wind and in a spot that has lots of radiant heat such as a block, brick or stucco wall facing south or west.

Lastly is how they were treated before they entered the winter. If they were mulched and had some mulch piled around their base they may come back from the base. If they were exposed like in a desert rock landscape they may not.

This is the trouble with common plant names. If the Texas sage is what I call a Texas sage it should be fine. It may have just dropped some leaves which many plants will do when temperatures get too low. Sometimes the difference between a deciduous plant (one which drops its leaves in the winter) and an evergreen plant (one which retains its leaves in the winter) is just a matter of temperature. In warm winters, deciduous plants may remain evergreen. In cold winters, evergreen plants may become deciduous.

Bottom line: wait. Continue to water them as dormant landscape plants. That is, once every week to 10 days or more depending on the soil and mulch. When other plants are beginning to put on new leaves give them two or more weeks. Watch where new leaves are growing from on the plant. Prune just above that point. If there is no new growth after one week, remove the plant and replace it.

Q: I have a young lemon fruit tree maybe 3 years old or 4, flowers last year all fell off, through the winter leaves are a light color green, not dark at all, some yellowish even. What is the tree missing to bear fruit and give me a dark green, healthy look? Help!

A: I assume this is Meyer's Lemon. Flowers can fall off due to wind, lack of pollination, because there were no active bees for pollination, drought and a variety of other reasons. When the flowers are out, you can just shake the tree lightly to dislodge the pollen and help achieve pollination but this should not be necessary unless the plant is indoors.

I would try using an organic fertilizer such as composted manures that are high enough in nitrogen. To be high enough, the carbon to nitrogen ration should be around 20 to 1. You also can try foliar feeding with a high quality liquid fertilizer like Peters or Miracle Gro. Usually iron applications to the soil such as KeRex will solve your yellowing problem on new leaves but not older leaves. The best solution are the organic fertilizers and foliar applications of a high quality fertilizer. Winter cold also can turn green leaves to a pale green or yellow.

Q: What can I do to keep my plum tree from bearing fruit? The tree is in the front yard and neighborhood kids pick and throw these all over the neighborhood.

A: You can break off all of the fruit-bearing spurs on the branches. These are short shoots along the branches. This is the only place where fruit will be produced. It will take you awhile to do it but that will stop its production for at least one season and possibly a couple more if you are lucky. You should then break off all new spurs when the leaves are off each year as you see them develop.

Q: I found the attached article in a local newspaper and it says not to prune during dormant season/winter. I thought that in general most of the pruning should be done when dormant. Do you think this is written for a different climate zone?

A: The only thing there I could agree with is not to prune anything that may have been damaged during the winter because you don't know how much, if any, has been damaged. We prune most everything now except potentially winter-damaged plants, roses and grapevines. We also usually don't prune anything that is a potential "bleeder," i.e., grapes, elms, etc. not because it hurts the plants but more because people get concerned that the plant is in some way hurt because of our choice of words (bleeding). The only other rule that might apply here is that we normally prune shrubs that flower during a particular month right after they finish flowering.

The article goes on to say that there is not much to do now in the garden. There is plenty to do particularly if you have fruit trees or are growing vegetables. Now is a great time to apply dormant oils and mulch, repair irrigation problems, weed to get rid of overwintering insects such as aphids, fertilize prior to new growth, whitewash fruit trees after pruning if necessary, I could go on.

Q: I've never had yuccas flowering before last year. Do you cut the central flower stalk after it blooms? If so, how close to the base should the cut be made?

A: You can cut the flower stalk any time you want. Many people like the flowers since it adds some interest to the landscape. If you don't like the flowers you can cut the stalk any time it begins to show.

Energy for growth goes into any plant process that is under way. If it is time to flower then the plant diverts energy for growth into flowering. After flowering, the plant diverts energy into seed production and building the capsules around the seed which takes quite a bit of energy.

Again, if you like the pods, then you can leave them and remove them any time you want. Any energy saved by removing the flower stalk or the seed pods before they mature is energy the plant can use for its growth.

When removing the flower or seed pod stalk you can cut it with a sharp knife or pruners as low into the point of origin as possible without damaging the mother plant or disfiguring it. You also can wait until the seed stalk dies naturally and it can be pulled out of the plant easily. Whatever suits your fancy.

Bob Morris is a horticulture specialist with the University of Nevada Cooperative Extension.