Trees that develop roots on the surface of the soil can be a major nuisance, especially when they are growing in the lawn. These roots make it very difficult to mow the lawn let alone walk across the it without tripping.
The shallow development of roots is partly genetic, but is mostly due to the oxygen and moisture content of the soil. When the soil oxygen level is insufficient, roots tend to develop closer to the surface than they otherwise would. This problem can be aggravated by watering too often and not giving air sufficient time to move back into the soil.
When a tree is planted it is often “guyed” by driving T-posts into the soil next to the tree, placing a wide nylon strap around the trunk and holding it in place with wire attached to the T-post. The purpose of guying a tree is to keep the root ball from moving. The trunk of the tree must move in order to develop diameter and taper guys should not be needed to keep the tree upright; if the tree is too weak to stand up by itself, it should not be planted. If you use the T-posts and guy technique, these should be removed within one year. Guys left on too long cut into the tissue and can cause tree death. When T-posts have been left too long, roots develop over the wings at the bottom of the post. When the T-posts are pulled out of the ground, roots are torn which is damaging to the tree. T-posts left in longer than a year should be cut off at ground level and not pulled out. If you guy a tree using this method, it should be done no higher than 18 inches from the soil surface.
The best way to guy a tree is to drive stakes through the root ball into the underlying soil to hold the root ball in place. One advantage of guying the tree in this manner is the stakes can be left in place forever. This method also allows the trunk to develop better taper and diameter as the trunk. The stakes are cut off even with the top of the root ball so they don’t protrude, eliminating a tripping hazard.
A lot of the trees and shrubs I have looked at are exhibiting very poor annual growth. The amount of growth a tree or shrub puts on each year is delineated by the circular scars on the shoot. The circular scar is the remnant of the terminal bud that develops for the next year’s growth. These buds are wrapped in protective scales and a scar encircling the stem remains when that bud begins growth the next year. Some of the trees I have looked at exhibit less and less annual growth over the last three or four years. Without adequate growth there are inadequate leaves to produce the food necessary to feed the plant and the tree or shrub suffers accordingly. Fertilizing trees and shrubs is an important maintenance requirement. In most cases one pound of nitrogen applied per one thousand square foot area around the tree or shrub is adequate.
In some instances the growth increment has been so poor I have been recommending two pounds nitrogen per one thousand. When you fertilize trees and shrubs the fertilizer should be watered in or it can be injected into the soil. Most likely your lawn care company or tree care professional can do this for you.
Fertilizing trees and shrubs should be done after leaves start to emerge, but no later than Aug. 1-15. To ensure your trees and shrubs are getting the appropriate fertilizer elements, ask your tree or lawn care company if they can do a soil test for you. Some companies offer soil testing to their customers to ensure your lawn, trees, shrubs, and other plants in your landscape are receiving the nutrients they require.
GJ Free Press columnist Dr. Curtis E. Swift is a retired horticulture agent with the Colorado State University Extension. Reach him at Curtis.Swift@alumni.colostate.edu, 970-778-7866 or check out his blog at http://SwiftsGardeningBlog.blogspot.com. He owns Swift Horticultural Consulting and High Altitude Lavender.
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