Answers to Questions about Growing Trees

Q. I have a good size section of trees (mostly White Pines and Douglas Fir) and shrubs on my property. Before I decide whether to hire a professional or do-it-myself to carry out the fertilization task, I'd like to gain a little knowledge on what's involved in tree/shrub fertilization. In general, what is used to fertilize trees and shrubs? Are any special tools needed to carry out this task? Is deep root fertilization any different than regular fertilization?

A. The best time to feed a tree is December, using a general broadcast of balanced fertilizer out to 50 percent beyond the canopy at the rate for grass. Mature or large trees don't necessarily require feeding. If these trees are more than 10 feet tall, I doubt there is much point in feeding them.

Q. I heard it's a bad practice to top trees. I'm wondering what would be the consequences of topping trees. Will it make the tree grow even faster, or the root system stronger?

A. Topping trees are simply butchering them. This serves no purpose other than to hack away at the tree. Pruning trees can help manage the height, shape, and density of the canopy. Pruning trees is a purposeful, careful activity the same as cutting one's hair. Unfortunately, I see many folks waste their money having the tips of branches trimmed to make bushy growth. It looks exactly as if a 5-year-old cut another 5-year-old's hair.

A properly pruned tree should not look any different, unless you knew exactly how it was changed.One example of extreme pruning would be fruit trees in production, such as peach trees with the open crown and controlled branches to facilitate fruit production and harvesting. Another would be a tree espaliered against a wall. In sum, topping trees does not make the roots stronger or the tree grow faster.

Q. I have a large maple tree in front of my house near the road. The leaves start falling as early as August and it is now spring and it is very slow to bloom leaves. Otherwise, it looks very healthy. I am thinking that it needs to be fertilized. I bought a 20lb bag of fertilizer and want to know the best way to fertilize the tree. I read that you should not spread the fertilizer less than 18" from the trunk and that you should drill holes into the ground at least 6" deep and fill these holes with fertilizer. The tree is near the road so I can only spread fertilizer on the left and right side of the tree and opposite the road. What exactly are the steps to proper fertilization? Does it matter if there is rain in the forecast? What if I just spread the fertilizer on top of the ground like you do with grass seed?

A. The best technique to feed a large tree is to apply a balanced fertilizer at the same rate as for grass around the tree and out to a point 150 percent of the coverage of the canopy. Just apply the fertilizer to the ground that there is around the tree. The best time is in December, so the feeding goes to the roots rather than to the leaves. The likelihood of coming rain is not important because the fertilizer won't burn the roots. Drilling and such seem to be valuable in some evaluations, but this seems to be a lot of effort unless you are feeding fruiting trees.

Q. I have about 40 maple and box elder trees on my lot. Two months ago, the farmer was crop-dusting his field and sprayed ten of my trees. I am not sure what he was spraying. Since then, all the leaves have fallen off and do not show any signs of coming back. Is there any chance of these trees coming back next year?

A. If the trees are mature, expect them to survive. You should see some new growth this year. If they do not, I suspect that he is liable for killing vegetation that is not his. This would be the case if he were not a farmer, just your next-door neighbor. You should find the farm manager and inform him of the situation. Tell him the date of the application and ask him for a copy of his application records for that day and for a copy of the MSDS sheets for the product used. I would also send some tissue samples in to be analyzed. If the farm manager does not cooperate, contact the department of agriculture in your area or the county extension agent for advice.

Q. I have an area in mind for planting a tree. It is currently in a large pot. It is a red maple, called Bloodroot and is supposed to get large and wide. I'm not too sure about the spot I've picked. I am planning to do a small raised area near my back fence approx. 8 to 10 feet away. The reason I want to put it in a raised area is, one, our soil has a lot of clay. Second, the area is a bit lower, and water will pool there after heavy rains. I live in Northern CA, in Sonoma County. My concerns are that part of my yard gets sun until about 1 pm in the afternoon. I'm worried about it being too hot for this maple. Currently the pot that it is in is directly across from where I want to plant it. It won't get much wind, as my yard is fenced in. Our neighbors have a large old silver maple, which helps shade the area later in the afternoon. Does this sound like a good plan? Will raising it with a raised bed help the wetness of the area?

A. Raising a bed for planting is a good idea, especially when it enables you to solve a problem with water standing in your yard. Be sure to raise the bed above the level the water stands, so the tree's roots don't start out sitting in the water. Japanese Maple should do fine in the sun. I have one in full sun.You mentioned your neighbor's silver maple. The Japanese Maple will not grow to be anywhere near as large as a silver maple. Japanese Maples generally peak at about 20 feet with a broad, fan-shaped, airy canopy. Although Japanese Maples grow slowly, the reward is in the colorful foliage.

Q. I need to plant two hemlocks that are seven feet tall, I was wondering if I should untie the burlap sack or just leave it tied
on to decompose. I would like to know of any good pointers anyone has on the proper planting of my hemlocks.

A. Prepare a planting hole 4-6 inches wider than the root ball. Dig deep enough so the top of the root ball is 1/2 -1" below ground level after planting. Planting slightly below ground level helps ensure adequate moisture for hemlocks. After placing tree in planting hole, cut and remove any twine, burlap and wire basket. Be careful not to disturb the root ball.

Back fill the hole with a mixture of original soil and some organic peat moss. Water deeply. Do not place soil on top of the root
ball. Apply a three inches layer of shredded hardwood mulch on and around the planting to conserve moisture.

Hemlocks are shallow rooted and very sensitive to dry conditions. They need at least 1" to 1 1/2" of water per week. Keep watering until the ground is frozen in the fall to prevent winter damage. Monitor for water logged conditions as poor drainage can be damaging.

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