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Q: I have a chokecherry which is getting taller than I want it to be — like 15 or 20 feet. Can I cut off some of the top to shorten it, or would that kill it?

A: If your chokecherry is growing the way that most of them do, it has more than one trunk. You certainly can prune it, but the best way is to treat it like a shrub with several stems, not like a tree with just one.

The too-tall trunks of the chokecherry will also be the biggest and oldest ones. Find their bases. Rather than shortening those trunks, cut them off as close to the ground as you can get. Other trunks will limit how far you can reach into the base of the chokecherry, but you should be able to cut within a few inches of ground level.

Remove about a quarter of the stems. Probably that will mean that one or two of them should come out. If the chokecherry is badly overgrown, you might need to take out three or four. The plant will then be more the height that you want. If it has produced a small forest of thin stems which threaten to flop over, cut them off too. Again, make your pruning cuts as close to the ground as possible.

Pruning time is up to you. If you cannot stand to have the tall foliage blocking your view for one more day, prune now. If you can wait until the fruit has ripened, prune after harvest. If you like to do all your pruning at once, wait until late winter. The only time that I would avoid pruning is early fall. If you make pruning cuts then, the chokecherry will start to grow new shoots immediately. Without enough time for the shoots to become woody before winter, the new growth would die in the cold.

Q: Do you pick all the flowers or the first crop of strawberries off new plants?

A: No, I cannot bear to do that, in spite of the fact that gardening books say it is necessary. Many years ago I did just what the books said, but I picked off the flowers only once. I cannot see any difference in the way that the plants grow if they try to make a few berries soon after they have established their roots. Perhaps strawberries grow differently in different parts of the country. Perhaps the advice was valid for old strawberry varieties. Perhaps it applies only to Juneberries, which make just one crop a year, although Juneberries generally do not bloom and fruit until they have been in a garden for a year.

I grow everbearing strawberries. Specifically, I grow 'Tristar.' They are a day neutral variety; that means they make three crops every year, instead of shutting down in midsummer as the old everbearing types do.' Tristar' berries are medium sized but packed with flavor. I am happy to trade taste for size.

First year everbearing strawberry plants make their crops a week or two later than older plants. Also, the first crop on new plants is sparse. By July, when they start to bloom for the second time, day neutral strawberries are bigger plants with a bigger berry crop.

I am adamant about removing strawberry runners, though. I set new plants about nine inches apart and let them fill in the spaces. I break the tip off every runner as soon as I see it. I think that crowded plants make fewer berries. The only exception I make is if a plant dies. When that happens, I watch for one runner starting on a nearby plant. I encourage the runner to grow into the empty space and pin it down, to create a new plant.

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Q: Our young blue spruces have brown tips which were not there when we went on vacation a month ago. We can't figure out the cause. Can you help?

A: You couldn't figure out the cause because there is no quick and definitive answer. I could think of a variety of possible problems, so I consulted Sylvia McNeill, who knows more about local tree problems than anyone else. She gave me some additional ideas but could offer no certain answer.

The difficulty is that there are at least three kinds of threats to your trees which would cause brown tips. The first, and the most likely, is environmental stress. You may be seeing the result of bad weather, last winter or early this spring. That can take months to show up. If the tips froze on some cold night, the damage is over. Next year's new growth will be affected only by future cold or wind. If you want to cut off dead tips for the sake of appearance, that certainly will not harm the trees.

Are you sure that the spruces get enough water? The shallow roots of spruce trees mean that they need damp soil near the surface, and June, while you were away, was a dry month. If water was in short supply, the spruces would sacrifice needles at the branch tips.

What kind of soil are the trees in? Does it hold water, or does it dry quickly? If it is not of the best quality, a yearly addition of an inch of mulch will gradually improve the soil. But do not fertilize your spruce trees at all. They easily gather the food they need from natural sources. Overfeeding them will only stress the trees. Let them grow at their natural rate.

A second possibility is that the young needles were eaten by insect larvae. There are several which might cause damage. Look right now for small caterpillars on branch tips. If you find any, cut off the infested tips and destroy them. That will stop the damage, and you will be reminded to check for bugs every year from now on.

If there are no larvae still on the tree, and the damage was caused by insects, it is over. The symptoms will not get worse.

That brings you to the third, and least likely, possibility — that the trees have fungal disease. In our dry climate this is a rare occurrence, but you can easily establish whether there is a disease by watching the trees. If the brown areas increase, the spruces do have a disease, and you need to call in an expert. If the brown needles do not spread, the trees are disease free.

The good news is that brown tips are essentially a problem of appearance. Trees are tough. They are used to coping with a variety of stresses, fighting them off, and carrying on with their lives. You would need to be alarmed only if every needle on the trees turned brown. Your blue spruces are dealing with the problems of an imperfect world. It certainly will do them no harm if you let them know that you care about them. We now understand that trees can see, hear, feel and remember better than humans can. It is safe to assume that they like your support.

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