1.  Field of the Invention
This invention pertains to garden implements, specifically planters, and particularly to those suitable for use in planting small trees, shrubs or other woody perennials. 
2.  Description of the Prior Art
Successful planting of woody perennials such as shrubs, bushes and trees (hereinafter collectively referred to as woody perennials) is more complex and demanding than planting annuals.  Woody perennials are long-lived plants that are set into their permanent locations.  Often they are planted for the fruit or flowers they bear.  Some fruiting varieties, even when planted properly, will not produce a sizable crop of fruit for several years until the plant has become well established.  A careless planting might unfortunately retard that crop by an additional year or two.  In addition, woody perennials and their roots are generally larger when planted than those of annuals, and thus require larger planting holes.  It is obvious that properly placing a large shrub in a large hole is more demanding than planting a small seedling. 
There are three main steps to planting a woody perennial.  First, a suitably wide and deep planting hole must be dug.  Second, the soil that is to fill the hole should be amended to aerate it and enrich it with the proper nutrients required by the plant.  Third, the roots of the plant should be placed at the proper depth in the hole and then covered with the amended soil.  This soil is then firmed down to eliminate any air pockets, after which the plant is then watered in.  At this point, the position of the crown of the plant [the place on the plant where the stem and roots meet] is critical.  Ideally, the crown should be at the soil level within the hole, and the top of the hole should be level with the surrounding soil. 
While the first two steps are not difficult for many gardeners, the third step often presents problems that many gardeners cannot readily overcome.  The main problem is that the gardener must have keen visual judgment to determine the proper vertical point at which to start placing the roots in order to have the crown located at the ideal position, i.e. at the soil level, after planting has been completed.  Unfortunately, many gardeners do not have this ability and thus produce poor results.  This is recognized in the book One Hundred Garden Plans by Andrew R. Addkison (Random House Inc., New York)--hereinafter referred to as Addkison--which states at page 25:
"A common mistake many people make in shrub planting is to bury the crown of the plant too low in the soil.  Set bushes so the soil level is almost the same as it was when you bought the plant at the nursery." 
Woody perennials can be purchased either container-grown with soil around their roots or bare-rooted.  While container-grown shrubs can be planted with relative ease and accuracy, planting bare-rooted shrubs is somewhat difficult and made more so whenever that shrub is to be set into an unusually large hole.  Many woody perennials are planted under one or both of these conditions: bare-rooted planting or planting in a large hole. 
Blueberries, for example, are usually planted under both of these conditions.  First, they are normally planted in their dormant season and therefore are planted bare-rooted.  Also, they require extremely acid and moist soil having excellent drainage.  Second, to meet this soil requirement, many experts recommend planting them in an unusually large hole, typically three feet wide and two feet deep.  As discussed below, blueberry planting epitomizes the difficulties of bare-root, large hole planting. 
The first difficulty occurs in the physical position the gardener must assume in this kind of planting.  It is an unnatural and stressful position which quickly produces great strain on the gardener's back and may even cause long-lasting medical problems.  Specifically, the gardener must crouch on his knees with his arms fully extended 18 inches [to the center of a three foot planting hole], holding the bare-rooted plant with one hand while spreading, then covering, the roots using the other hand In this position, the gardener's back is virtually horizontal, with nothing, apart from the gardener's back muscles, supporting the weight of his torso.  As a result and after a fairly short period of time, intense pain occurs in these back muscles.  If the gardener is planting alone, a long time will be spent in this painful position, since all the work of spreading and covering the roots must be done with one hand, while the other hand holds the plant.  Spreading the roots can be done rather quickly.  However, covering them with the necessary three or four inches of soil will take much longer.  This occurs because these three or four inches of soil must also be added to the entire three foot planting hole, and this is a large volume of soil to place.  Since the gardener has only one free hand to accomplish this while still on his knees, he is forced to use a small hand tool, e.g. a trowel, to add all the necessary soil.  It is nearly impossible for a gardener to use a large heavy tool, e.g. a spade, with one hand particularly while he is crouching on his knees. 
Another difficulty confronts the gardener while he is in this painful crouching position.  Specifically, he must try to determine the proper vertical placement for the crown while looking down on the plant, with the nearest reference point, i.e. the rim of the planting hole, being some 18 inches away.  It is difficult, if not impossible, to make an accurate judgment in this position.  Instead, the gardener must drop his head to one side of his body in order to view the vertical position of the crown in relation to the rim on the far side of the planting hole, much like a land surveyor sights a tree.  If several sightings are needed, this increases the amount of time the gardener must spend in this back-straining position. 
A third difficulty arises when the planted perennial is watered in.  Loose aerated soil in the planting hole will lose a good deal of air when watered and hence may sink quite a few inches, taking the crown of the plant with it.  This explains the condition referred to above by Addkison.  A sunken planting is undesirable, both aesthetically and for practical reasons. 
To correct a sunken planting, the gardener has three choices, all of them harmful to the plant: [a]he can add more soil to the planting hole, thereby burying the crown; [b]he can pull the crown of the plant up to the proper level, thereby damaging the roots and possibly killing the plant; or, [c]he can dig up the plant and start over, thereby causing much stress to the plant and considerable strain for himself, with no guarantee that he will plant more successfully the second time. 
Clearly, the successful planting of many woody perennials presents numerous difficulties and imparts significant physical strain to the gardener which the present invention seeks to correct.