The next time you plant a tomato plant, look at the lower stem. Most likely you will see little white pimples on the stem. As most of you know, these are the beginnings of roots. It is easy to get tall starter tomato plants but planting them deep best rectifies that. The deeper you plant, the more roots you get, and the better the plant.

Annuals with a single stem are quite forgiving of planting depths because they share the tomatoes ability to a lesser extent. If the annual appears to form a clump, then you must be careful to neither bury nor elevate it significantly. Gerbera daisies are the first annual to come to mind that will quickly get into trouble with improper planting.

Since many or most perennials are clump forming, be careful with planting depth. The rule of thumb in general is to mimic the depth in the pot you purchased.

Bearded iris need extra precaution. The rhizomes must be almost laid on the surface. If they are not exposed when you are finished planting you will quickly get into trouble. They will grow, but not form flowers. It seems to me that over time they burrow deeper into the ground, but I've killed a number of iris before I learned that trick.

It might be worth a limited bit of experimentation to try planting some a bit deep, maybe half an inch or so, to see whether it will slow growth. It works with daylilies. If they are planted a bit deep they grow rather slowly. To get bigger clumps for division quickly, plant them a bit shallow.

Grafted plants are a bit more of a dilemma. Grafting, of course, sets a desirable plant on roots of a similar but less desirable plant. This can occur for one of two reasons. A weak growing top is put on vigorous roots to increase growth or a vigorous top can be placed on weaker roots to slow growth. It is also possible to use grafting to get some plants that are almost impossible to root on their own.

It is important to know which is happening. You often plant the weak top, strong root combination deep, even burying the graft, in hope that the weak top will put out some roots. If this happens, you will get a stronger plant. The winter witch hazel and tree peonies are two examples that quickly come to mind.

The strong top, weak root combination is used to produce dwarf fruit trees. Here it is necessary to keep the graft just above the ground level to prevent possible rooting. As a matter of fact, the higher the graft is out of the ground, the smaller the finished tree.

In both cases the more of the rootstock that is exposed to the surface, the more suckers you can get. These need to be removed, since in ornamentals they are generally much more vigorous than the desired plant.

This whole article formed in my mind after reading a bit of a pamphlet that focused on proper planting of trees. With larger woody plants it is important to nearly match the previous growing level.

If you are using something that is bare-root you should be able to spot the previous soil line rather easily. If your plant was container grown match the container surface to the ground line. The pamphlet gave a margin of error of only one inch up or down.

It also emphasized that care must to be taken to get the hole no deeper than the root-ball or container. They were concerned that gravity working with rainfall would sink the tree too deep if the hole was dug too deeply.

Planting depths are critical to plant growth and survival. Learn a bit about what you are planting and try to match the ground level to the level it grew at before, unless you have a good reason not to.