Documents: Latest From: Shauna Dobbie:

10 Neat Things About Roots
by Shauna Dobbie
by Dorothy Dobbie

The Local Gardener magazines, Ontario Gardener, Manitoba Gardener and Alberta Gardener, are published by Pegasus Publications Inc.

Drawing on her 30 years' experience as a senior executive in the magazine publishing industry, Dorothy launched Manitoba Gardener in 1998, initially running the business out of her home. Two years later, Dorothy's daughter Shauna, living in Ontario, jumped into the fray with Ontario Gardener. And two years after that, they started Alberta Gardener. Visit us at and register for our "Ten Neat things" newsletter. Watch Shaw TV for garden tips and Listen to CJOB for the Gardener Sundays at 9:08

February 27, 2011

1. Attack of the sewer root. Homeowners dread the dastardly sewer root; however, contrary to popular belief, the roots have no evil intent. They simply exploit leaks from cracks that already exist in old sewer or water pipes. You would do the same if you were next to an unlimited supply of water and food. Tree roots will not invade foundations or crack basement walls.

2. Root pressure. It's true that there is such a thing as root pressure, but this refers to the force that moves water from underground sources to the branches that are sometimes hundreds of feet above ground. It's also known as transpirational pressure, referring to the force that helps the tree pull water up to leaf tips as moisture exits the leaf stomata, the tiny pore-like openings on the leaves. It's not true that roots can exert brute force on innocent cement.

3. When is a root not a root? Not all roots grow under the ground and not all underground growth is a root. Some plants send out aerial roots (epiphytic orchids for example) and some underground growth is stem: rhizomes such as canna, ginger, or lily-of-the-valley, are swellings in the roots that store food and grow horizontally just below the surface of the earth, sending out lots of growing points.

4. Root buddies. Certain fungi known as mycorrhizae form a symbiotic relationship with roots. It's a rapport made in heaven. The fungus gets access to a constant supply of carbohydrates while the plant gets better water and nutrient absorption.

5. Apical meristems. We think of these growing tips as aerial growths, but roots have apical meristems, too. Apical meristem cells divide continuously and will grow in any direction, wherever they can find water and mineral nutrients. They won't grow in dry soil.

6. Root caps. The tip of a root is called the root cap. These very tiny, tough cells have the job of pushing through soil. They protect a layer of tiny downy hairs that have the job of absorbing water through the process known as osmosis.

7. The underground world of roots. Roots can grow as deep as a tree is tall depending on the species and on the soil environment. The deepest roots are usually found in the desert and in temperate coniferous forests. The shallowest roots are in the tundra or on stony mountain outcrops. But most roots, especially in clay-based or compacted soils, grow near the surface of the earth, within the top 12 to 18 inches of the surface where air, water and nutrients are readily available..

8. The wide, wide world of roots. Some tree roots reach out, usually about three times the spread of the branches. Trees also put out tough anchor roots to keep them from falling over in a high wind.

9. All tapped out. Most trees start out with tap roots that gradually disappear as the lateral feeder roots appear. An exception would be trees in sandy areas where tap roots are necessary to provide a strong anchor or where water can only be found at great depth. Oak and walnut trees start out with very strong tap roots, which makes these trees hard to transplant when they are young.

10. Tap roots ensure survival. Unlike trees such as elms and maples with produce millions of seeds that have a dispersal mechanism, nut trees produce relatively few seeds with no dispersal system. The must rely on animals such as squirrels to transport their seeds. Unless they are harvested right away, the acorn puts down a tap root to anchor it to the ground and keep it viable until conditions are right. And acorn buried at the root of an evergreen can lie semi-dormant for many years until its host dies and makes room for the new oak.

  • New Eden
  • Kids Garden
  • Plant a Row Grow a Row