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Published February 25, 2011, 12:00 AM

Hortiscope: Toppled birch tree worth effort to try to save

Q: I have a weeping birch that is at least 25 years old. It’s gorgeous and was doing well until we had a lot of wet weather two years ago.

By: Don Kinzler, INFORUM

Q: I have a weeping birch that is at least 25 years old. It’s gorgeous and was doing well until we had a lot of wet weather two years ago. The soil must have become so wet that the tree tipped over and exposed some of the roots. It landed on a fence, so it didn’t fall all the way to the ground. I had it put back up and staked.

However, in August, we had a bad storm that toppled a maple tree onto the birch, so it was again pinned to the fence. I again had it put back up and staked. Last week, we had a wet, heavy snow that broke the wires holding up the tree, so the birch is back on the fence. As you might suspect, all this is costing me money. The cost is about $400 each time I have the tree put back up.

I’m trying to figure out whether I should keep trying to save the tree or if it will ever be OK. It’s obvious that the weight is not distributed evenly because it tilts toward the fence and all the growth is on that side.

Do you think that I could get it replanted in some way so the tree would stay upright? I’m also wondering if the roots have been broken so badly that they might not be able to support the tree. Should I prune the tree so that it’s not so heavy on one side? (e-mail reference)

A: I admire your determination trying to save this beautiful tree! I have one in front of my house that is about the same age as your tree. For the last six or so years, I’ve had an International Society of Arboretum (ISA) certified arborist do some balanced pruning for me because it is close to our house. I would suggest giving one last attempt at saving the tree. Get a qualified ISA certified arborist out this spring to do some selective or balanced pruning.

Birch trees are worth the effort and expense to keep around for as long as possible because they add so much grace and character to the property and the neighborhood.

Q: We have a tropical tree hibiscus that never has been outside. It blooms regularly, but the leaves don’t look healthy, and the plant doesn’t grow. We fertilize it on a regular basis with one-fourth teaspoon of Miracle-Gro to a gallon of water. Can you help? (e-mail reference)

A: It sounds like your hibiscus might be in a rut. Give up on the fertilizer and set it outside once this cold winter is over. This will give it an opportunity to experience day-to-day changes in light intensity, duration and temperature movements. I have seen this work miracles on plants.

I actually do believe that plants can get cabin fever the same as humans do, so plants respond favorably to a positive change in the environment. Give it a try. That’s the best suggestion I can give you.

Q: I received some tulip bulbs from Holland as a gift. The instructions for my zone said to plant them sometime in the fall. I planted the bulbs in late August. A cold spell hit at the beginning of November, but by late November, we were back to warm temperatures, so eight out of 20 bulbs sprouted. I babied them through some freezing spells in December.

Most of the plants are growing new leaves but none have bloomed. Will they bloom this spring? All of the plants have bent leaves from the blanket I put over them to keep out the cold. Should I trim those leaves? (Tampa, Fla.)

A: August in Tampa is too soon to have planted those bulbs because it is too warm in your part of the country during that time. You should have waited until November to plant or at least checked with the Florida State University Extension Service to find out if there was an even better date.

Since the bulbs were from Holland, I wouldn’t be surprised if they need to be refrigerated for 60 to 90 days before planting to get the flower buds to start. From your description, the plants don’t like to set flower buds, so I doubt that you’ll ever see any flowers from these bulbs. Sorry.

Q: I have been doing some research on spider plants because I am interested in growing them indoors. I came across your website with many people asking questions, so I thought I would ask you to clarify some things.

I live in a carpeted unit, so I can’t keep any plants in pots full of soil. I can keep plants in water-only containers. Can I keep the plants in the containers for the life of the plants? I thought of putting one spider plant baby in the bathroom, one in the kitchen and one by a windowsill. How often do I need to change the water? (e-mail reference)

A: Yes, you can keep the baby spiders in water. Change the water at least once a week and be sure to maintain the proper water level between changes.

Q: I winter my potted begonias in the basement. This year, they did not seem to go dormant, so I have these long sprouts growing everywhere. Is it OK to cut these off or will I kill the plant? Thanks for any advice you can give me. (e-mail reference)

A: Cut off the long sprouts as soon as possible because they are draining energy from the tubers. The plants may be too far gone by now to be saved, but it is worth a try.

Q: I planted three eastern arborvitaes next to my house. I have drain tile along the house. Will the root system of the arborvitae reach the drain tile? (e-mail reference)

A: I doubt the roots will reach down that far unless the drain tile is leaking.

For the most part, the arborvitae will follow the flow and movement of the surface water and drainage characteristics of the soil.

Q: I live in a neighborhood with a long fence at the top of a bank sloping away from the houses. Probably 150 cottonwoods have sprouted along the fence in the last five years.

Now the neighborhood association wants to kill them by cutting them down to a foot off the ground and applying some sort of poison on the stumps to kill the root system. Is this a viable option? Do you recommend this method? Is there a product you recommend? If birds rest on the stumps, will the poison kill them? (e-mail reference)

A: The effort will be far more effective if the trees are allowed to sprout spring growth first. Once the leaves have fully expanded, cut them back as you describe. After that, apply a herbicide to the outer ring of the stump where the cambium is located. The herbicide will be taken into the roots.

Contact your local Extension Service forestry or horticultural personnel for the product or products that can be legally used in your state.

Q: I use your website quite often as a resource. I have three hibiscus plants that are wintering indoors. Two of the plants went into a rest period but are now starting to grow new leaves and bloom. The other plant is dormant because it went into a rest period a bit later than the other two. All three are in the warmest room in our house. They are at a south-facing window to get as much direct sunlight as I can give them.

When should I prune the trees? I would like to use the cuttings to start a few new bushes for family and friends. Various sources on the Web and print say to prune at different times of the year, so I am confused. Should I do it now before spring arrives? The plants probably will go back outside for the summer. We also have key lime and meyer lemon trees in the house. They are with the hibiscus trees. Both trees bloomed this year.

We did not know that lemon trees need to be pollinated, so we lost our chance for lemons this year. I did try to pollinate the lime tree with a small paintbrush and I think a few of the blooms may have been pollinated.

Is there anything I should do while we are waiting for the limes to grow? Do they only set flowers once a year? How often should I fertilize my larger, potted plants? (e-mail reference)

A: If the hibiscus plants are dormant, you can prune them. Reduce them in size if you wish and use some of the cutting material to start new plants.

Fertilizing is most effective when the plants are starting to show evidence of new growth. For as long as new growth continues, fertilize every 10 to 14 days using a diluted solution. Check the citrus and lime trees carefully for the start of any citrus scale. These pests often catch the owner by surprise. When they are noticed, it usually is too late to save the tree. There are all kinds of scale insects, such as cottony cushion, San Jose, scruffy and oyster shell.

Look for anything unusual along the stems, such as bumpy surfaces or branches that are sticky from exudate. If they are confined to one or two branches, prune them off and dispose.

Q: My cousin gave me a jade plant that has pieces falling off. He said this was normal, so I’ve been potting them to grow new plants. However, in the last day or two, a couple of branches have fallen off. I’ve attached photos.

It has grown taller while I’ve had it. The jade is not in direct light, but it does get a lot of light. I’m in Scotland, so it does get cold here. I don’t water it much during the winter. (e-mail reference)

A: Thanks for the nice photos of your plant and the new starts. Jade and other houseplants, notably the ficus species, will drop foliage when temperatures fluctuate too much in the environment. The plant will read the environment as being potentially hostile and begin to protect itself by dropping some foliage.

The more consistently you can maintain the temperature and humidity levels in your room, the better the plant will grow. Some defoliation will always take place, but it shouldn’t be to the point where it is a daily mess to clean up.

To help correct the spindly appearance, I would suggest cutting the tallest branches back to just above a node or leaf to encourage branching. When new growth becomes evident, begin a monthly fertilization regime with a dilute solution of houseplant nutrients.

While you are smart to not overwater during winter dormancy, don’t overdo it when you do start to water. Going from no water to a total soaking can cause foliar drop. Anything you can do to prevent going from one extreme to the other will result in a better looking and healthier plant.

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail