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Published June 08, 2015, 07:47 AM

Don Kinzler Q&A: Maple trees sensitive to planting depth

Q. We have two maple trees in our front and back yards. I noticed last fall that the bark had split on the trunk of one tree. I was worried that it would have problems this spring, but it is fully leafed to the end of every branch. Do I need to be concerned, and is there anything I should be doing about the trunk? -- David Flakker, Fargo

By: Don Kinzler, Forum News Service

Q. We have two maple trees in our front and back yards. I noticed last fall that the bark had split on the trunk of one tree. I was worried that it would have problems this spring, but it is fully leafed to the end of every branch. Do I need to be concerned, and is there anything I should be doing about the trunk? -- David Flakker, Fargo

A. Growing maples in the Red River Valley can be tricky. They are happier in the naturally forested regions extending eastward in Minnesota. Many of the maples offered for sale in our area are winter hardy, but they struggle in the heavy clay alkaline soil. They prefer lighter, forest-type soil.

So maples start off at a disadvantage here, which makes them more susceptible to other problems such as iron chlorosis, which is a yellowing of the foliage due to the tree's inability to utilize iron from the soil. (Iron products available from garden centers help correct the condition.) Also, because their bark is smooth and thin when young, they are more susceptible to winter frost cracks and winter bark sunscalding. Wrapping tree trunks up to the lower branch in fall helps. Wraps should always be removed in spring, so trunks can breathe in summer.

Maples are extremely sensitive to planting depth. Often adverse symptoms aren't visible until years later. If the trunk goes straight into the ground like a telephone pole, you can be suspicious. Instead, the trunk should flare out slightly, becoming wider before it enters the ground. To check planting depth, remove soil from around the base of the trunk with a trowel. Dig until you locate the first large root that branches from the tree trunk. The first root should be just below soil surface. If it is 3 inches or more below soil, it's too deep. Sensitive tree species can exhibit bark cracking, branch dieback, and susceptibility to diseases and insects.

Bark and trunk cracks can be caused by several of the above conditions. Once cracking has occurred, there are no paints, sprays or other treatments that are effective. Trees do have the ability to heal wounds and cracks, so it's a good sign that your trees are showing healthy spring growth.

Q. I read your comments about quack grass problems in iris plants. Can the product you mentioned, Grass-B-Gon, be used on peony plants? I have several early blooming varieties, so is it best to wait until after blooming? -- Jeanne Radcliffe, Fargo

A. The Ortho product Grass-B-Gon and other brands containing the active ingredient fluazifop grass-killer can remove quack grass from peonies. There's always the potential for blossoms to be damaged or spotted by many types of sprays. You can wait until flowering is finished, or be careful to direct the spray onto the quack grass while avoiding the blooms. The product only kills grasses, so it won't harm peony foliage.

Allow the quack grass to grow before spraying, so it has at least 6 inches of top growth to absorb the product. Grass-B-Gon is slow acting, but after about two weeks the grass will turn dull gray-green and eventually to brown. A second application is sometimes needed because quack grass rhizomes contain dormant buds that can become activated after the other plant parts are killed.

Q. I'd like to plant strawberries, and I've noticed some types are called everbearing and some are called June-bearing. What is the difference, and which type would be better? -- Jim Teufel, West Fargo

A. Everbearing varieties produce a crop in late June/early July with a second crop starting in late summer continuing until freeze-up. Recommended varieties include Ft. Laramie, Gem and Ogallala. June-bearing types produce their entire crop in late June through early July. Varieties adapted to our area include Honeoye, Trumpeter, Stoplight, Glooscap and Crimson King.

Both everbearing and June-bearing types are capable of producing total yields that are similar. It just depends whether you would like the crop consolidated into a June-July period (June-bearing), or divided between early summer and late summer (everbearing).

If you have a gardening or lawn care question, email Don Kinzler at ForumGrowingTogether@hotmail.com. All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.

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