Trapping heat essential for young Meyer lemon trees

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The Las Vegas Chrysanthemum Society will hold its annual mum plant sale from 10 a.m. to 3 p.m. on Saturday at 2600 Fargo Ave. For more information and directions, call the master gardener hot line.

Question: I have two 3-year-old Meyer lemon trees in large pots in the east- and south-facing backyard of my Henderson home in the same condition as the citrus trees described in your May 2 column (lost leaves, buds and flowers left with some signs of fruit development). I have other citrus trees in pots and in the ground in the east- and north-facing section of my yard. This area between two houses gets sufficient sunlight and cold weather protection. The in-ground trees in this area have had little loss of leaves and produced ample fruit last year. There is enough space to add two more trees. Would it be advisable to plant the potted 3-year-old trees in the ground at this time of the year or wait until the fall, cooler weather?

Answer: I take it from your description that you think the area where you want to plant them is well protected from winter cold and wind. The ideal spot would be an area out of the wind and warmed by walls that reflect heat during the winter, with heat that is not moved out of the area by wind.

You want that south-facing wall to gather heat during the winter days and radiate it back into the area at night. Plus, you want the area protected enough so that any warmth radiated back at night is not moved out of this microclimate by air movement. Not that you have it, but any sort of partial canopy or roof over the area helps to trap heat as well.

If you think this somewhat describes the area, I would go ahead and put them in the ground with one caveat: Be prepared that one winter day, some time in the future, temperatures may drop into the low teens again and you may lose it. I hate sounding like Chicken Little, and this would be a rarity, but a possibility.

As long as you can maintain the rootball when you plant it, and that rootball does not fall apart, then you could plant it now. If you cannot plant it with an intact rootball and fear that you do not have the help to get it into the ground in its entirety, then wait until late September.

You can plant container plants almost any time of the year if you have a green thumb. If you are not confident about your green thumb, then I would avoid the months of June, July and early August, as well as December and January.

Q: In the third year of my Thompson seedless grapevines, quite a few branches of grapes are starting to form. However, a few appear to be drying up. Last year foliage was plentiful, but with only four or five branches of grapes, which dried up immediately after forming. Is there a solution to this problem or is this a usual occurrence during the early growing season?

A: I am concerned about how you might be pruning your vine. There are two general methods of pruning -- pruning by the spur method or the cane method.

When pruning back the vines of Thomson Seedless -- and this is one of the few table grapes that are pruned this way -- the canes must be pruned to spurs or canes long enough to include at least 12 buds. In other words, you don't want to prune canes or spurs shorter than about 12 to 18 inches long. Shorter than this may lead to unfruitful canes or spurs.

Outside of this, the only other things I can think of would be mechanical damage to the new bunches being produced, some late freezing or cold damage. We lost quite a few spurs this past winter at the orchard due to late freezes.

Q: I have planted my 3-foot fruit trees, All-in-One almond, Bonanza peach and Blenheim apricot using 50:50 ratio of Nevada Organic Compost without stakes. Would they need stakes? I also wanted to plant some grape vines, but read that it would take four years before one can get fruit after training it on a trellis, so decided not to get them.

A: You could probably get grapes in about three years off new vines. In fact, depending on the size plant you select, you could get them the first year. And you do not need to trellis grapes. You can just stake them like a small tree and get production. It all has to do with how they are pruned.

As far as stakes are concerned, if they are planted correctly and they are small enough, you will not need stakes.

However, stakes would be a small insurance investment if you are not sure if you planted them well. Stakes will secure the roots from moving in the soil and tearing once planted. I would probably stake them if you are unsure.

Also, I would thin the canopy of newly planted trees if you do not stake. Thin about one-third out of the canopy at the time of planting. You do not have to do this if they are staked. You usually have to do some pruning at the time of planting anyway to shape the tree and get it going in the right direction from the start.

Q: I have a mature fig tree, about 18 feet tall, that seems very healthy. It produces thousands of very small figs which eventually drop and create a large cleanup job. I like the tree for its shade, but I don't want the figs. Is there anything that can be done to suppress fruit formation?

A: Figs will produce two and sometimes three crops each year. The first is called the breba crop and formed on last year's growth.

The only way to eliminate the early figs is to prune out all of the previous years' wood. That is, any wood made by the tree in, let's say 2005 as an example, would have to be cut off. This would only get the early figs. The later figs, what we call the main crop, would still come on. The main crop is only produced on this season's wood. In other words, the 2006 crop is only produced on wood made in 2006.

Sorry, but there really is no way to eliminate all of the fruit every year unless you just pulled them off as soon as you see them when they are small. This could be very easy, though, and fast by just rubbing them off when they are the size of a grape or smaller.

Q: I had large green cutworms on my tomatoes last year. Actually, they were on all of my nightshade plants. Before they strike again, what can I use to kill or keep them away?

A: These were probably not cutworms. There are two pests you will be concerned with -- the tomato hornworm and the tomato fruitworm.

The fruitworm gets into the fruit. The hornworm is the bigger pest of the two. This is a "worm" or larva of a large moth called the hawk moth. The larva are green with a racing stripe down the side and a spine on its rear end. They will devour plants in a matter of days.

The best way to get them is to use Bt. This would be called dipel or thuricide in the nursery. It's completely safe for us to use. You can buy it as a powder and sprinkle it on the plant like baby powder or as a spray and mix it up and spray it on. Do this starting now and redo it about once a week or two. The adult is flying now and laying eggs. Follow label directions.

This spray also would be good for controlling the grape leaf skeletonizer, which devours grape leaves in about July.

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