In early spring, many trees are offered for sale with the roots and soil contained in burlap and held together by twine. These trees have been grown in the field for two, three or many more years and are harvested in winter, dug either by hand or machine.
The advantages of buying a field grown tree is that you obtain a large sturdy tree that will immediately make its presence known in the landscape. The disadvantage is that in the harvesting of the tree, many roots are left behind, requiring a bit extra care to ensure survival. It may take several years for the tree, especially a larger tree, to fully recover and begin to grow vigorously again.
Before You Buy
When you go to the nursery to purchase a tree make sure you examine not only the tree, but to some extent the ball itself. Does it seem large enough to support this tree? A very large tree with a small root ball may mean that the tree will have a difficult time making the adjustment. There are nursery standards that dictate how large the ball must be based on the thickness of the trunk, so most often the ball is sufficient. If the root ball appears loose with the ties sagging, it might not hold up very well in transport to your landscape.
Planting a balled and burlapped tree requires a few extra steps to do it correctly. Since you are buying the tree including the roots and the immediate soil that the tree was growing in, you will want to treat the ball much like a case of eggs. Handle it with care, do not drop it, step on it or otherwise abuse it.
When you have made the hole the proper depth and width, carefully place the root ball in the ground, fill the hole half way up, and then cut the twine that is tied tightly against the trunk, taking care not to scrap the bark. Open up the burlap partway and using scissors, cut the top one-third of the burlap completely off. Inspect the ball to make sure that there is not another layer of twine wrapped against the trunk, which is often the case in larger root balls. If so, remove this twine.
Get down on your knees at this point, and now look at the soil against the trunk. Remember, field grown trees are grown on level land. A root ball is round. Soil is most often pushed up against the trunk to make the root ball stable. This soil must be removed. Taking the backside of your pruners (or some other tool), gently scrap away the soil that is against the trunk until you see just the beginning of the top of the first root. Make sure you have anticipated this in your initial digging of the hole; otherwise the tree will be planted too deep. Again, be careful not to scrap the bark. All this care may take an extra 10 minutes. It’s worth it when you consider how many years this tree has been in nursery production to get to this point where you are now in charge.
To complete the planting, add the rest of the soil you removed back into the hole and then add a layer of mulch–perhaps two inches. Make sure you keep the mulch six inches away from the trunk as the trunk tissue layer is not designed to stay wet.
Now that your tree is properly planted, water responsibility comes into play. If the tree is an evergreen, it is losing water every day through the needles. That water must be replaced. Until the tree becomes established, which can take a year or longer, you have to provide additional water so that the few remaining roots can absorb the required water. At the same time, you cannot let it get soggy, as that will injure the roots and potentially kill the tree. The same thing applies for deciduous trees, however when they do not have leaves, the only watering required is the initial watering which also helps reduce large air spaces in soil from the planting.
About 95 percent of balled and burlapped trees survive, even though if you look at the root system of a balled and burlapped tree, it is amazing how few roots are in that ball of soil. There are typically four or five larger roots cut or sheared off along with a few minor roots. What happens is that the tree will resprout new roots from the vicinity of the severed root. These are the roots that you must protect and preserve by correct watering, especially during the first summer.
John Monroe owns Architectural Trees in Bahama, NC, specializing in conifers, Japanese maples and other fine plants.