Planting and Transplanting
Tips for Trees and Shrubs

Over the decades it takes for a tree to mature, fields become housing developments and shopping malls, new houses appear, additions are made, construction damages roots, and sunny backyards become shaded. It is often luck as much as wisdom that results in the perfect placement of a tree or shrub. Change happens and often has a significant impact on plant material. If you need to move a tree or shrub, you're not alone. In fact, confronting the need for transplanting should be highly applauded. It's easier to ignore the signs and just lament the changes.

In general, trees with trunks larger than a few inches in diameter should be replaced, not transplanted. If you're determined to replace a large tree, nursery grown stock that has been root pruned, on a regular schedule, stands a greater chance for survival. Large field dug or transplanted trees sometimes lose more roots than they can replace and cause a tree to suffer irrevocable damage. If you have a few years to anticipate transplanting a tree, you can systematically begin root pruning to prepare for the move.

With shrubs, it sometimes depends on the species more than the size. You may want to start with a new plant if the species is quick growing and inexpensive or if the shape is mangled from desperate pruning. Otherwise, if you can physically move it, it can be transplanted. The root systems of most shrubs don't spread as far as trees, so the chance of getting enough roots to sustain the plant during recovery is higher.

In recent years, scientific studies have brought to light new advice for planting that contradicts the practice of decades. Though the information has been circulating within the horticultural community for over a decade, it is just gaining widespread approval. Be warned, your favorite gardening books might not be up to date, and you might find individual landscapers wedded to their old ways. The new concepts aren't difficult to grasp and make good sense. They are based upon what actually happens underground rather than what was thought to be happening. The proof? Someone painstakingly dug up, followed, and cataloged the depth of every root on the target study trees. They found that roots did not stop at the drip line, as old lore would have it, but sometimes extended more than a quarter mile. Most all the roots were in the top 18-20 inches of soil where the nutrients, organics, bacteria, bugs, and worms congregate--the environment in which root systems thrive.

The hole needs to be twice as wide as the root system, not twice as deep, since most roots will grow laterally in the top 18 inches of the soil. This is shockingly obvious if you've ever seen the massive, shallow root-balls of huge trees uprooted in storms.

Don't enrich soil in the planting hole unless it's terrible. If it's that bad, the entire area of the future root zone should be enriched, not just the hole. Otherwise the roots won't venture out of that nicely enriched hole. Don't fertilize for at least one full season. The plant needs to focus on root development, not top growth.

Don't make a saucer at the base of the plant/trunk to catch water. Mulch a 3-4 foot radius starting about six inches away from the trunk. If necessary, make your depression at least a foot out. Channeling water to the base of a plant encourages rot.

Prune only dead or damaged branches at planting, or branches that are truly dead after transplanting. Wait a year to prune for shape. Don't use sealants or paint on pruning cuts.

Stake only in windy areas and allow for plenty of flex. Movement tells a plant where it needs to put down extra roots for stability--roots that will ultimately make it less prone to being blown over.

Before you buy any plant, try to assess its health. Look to see whether roots are protruding out of the container and if so what kind. If you only see healthy, white root tips, the plant has probably been repotted on a regular basis. If the protruding roots are woody, fibrous, and long, the plant has been pot-bound for some time and is probably stressed. Check the soil layer at the top of the container. A pot-bound plant will have little loose soil showing. Shallow watering practices can also encourage roots to congest at the top.

Pay close attention to the form of the plant. If what you want is a single stemmed tree, search for one. If you have to discourage other already vigorous stems, the results won't be nearly as good. If what's showing above the soil looks distressed, misshapen, or diseased, don't buy it. Even if you choose your plant carefully, you never really know what the state of the root system is until you get it out of the pot--so buy from a reliable source.

There are differences between planting a tree or shrub that is balled and burlapped (B&B), and one that is container grown. Remove all the burlap and wire from a B&B plant. Is this difficult? You bet. Do most nurseries and landscapers remove it all when they plant? Not usually. They may tell you the burlap need only be pulled down beneath the soil line where it will disintegrate, that roots will grow through both it and the wire. But I've dug up plants that have been in the ground for several years where not only have the roots not grown through the burlap but it hasn't disintegrated. Yes, roots can easily grow through a wire frame, but when those roots fork at the wire, or enlarge in diameter, they can be girdled or split. The stresses these problems cause may take years to become visible above ground, disassociating them from their true origins--just as trees damaged during the construction of a house, or widening of a road, often look fine for years before they decline or die.

I've also found that most large B&B trees have a predominantly clay based soil. This is desirable in the wrapping process because it holds together well, retains moisture, and allows large plants to be moved by fork lifts and front end loaders. However, there are few roots that survive on the bottom of heavy B&B plants. The compression often kills existing roots and inhibits new growth. The soil at the bottom and middle of a large B&B is often dried out and cement-like. Chip that out too.

Does this mean you should shy away from B&B? Not if you're determined to plant large material; often it's the only choice. If a tree has been B&B'd for a full season, looks healthy, has good shape, and has leafed out well, you know it has sufficient roots to sustain health. That will only improve once you've done a good job planting it. By contrast, a field dug tree may lose more roots than can sustain its current growth and be set back in recovery for several years.

Once the plant is free of its container, you face the most important step in planting as well as the most neglected: root untangling. As Bob August from Nasami Farms says, "Mangle, mangle, mangle!" I prefer the term "root prune" but agree that "mangle" makes a more lasting impression.

When confined by containers, roots grow in circles and twist around themselves in a strangling pattern that will continue until forcibly disrupted. A quick solution is to make vertical slashes in three or four places around the root-ball. This breaks the circle and allows new roots to redirect themselves more easily into the surrounding soil. I prefer to untangle and prune what roots I can, knock out the container soil, and spread roots out into the hole to speed up the process. I have often dug up shrubs that have been in the ground for several years that could easily be replanted in their original containers because the roots were never discouraged from breaking the container habit.

Roots are the most important part of a plant and the heart of success in planting. Think of them as straws: they provide the vascular structure for nutrients and water to travel up to the visible, growing part of the plant. If a straw (or root) is bent or squashed it doesn't work--no food or water circulating--dead plant. It's impossible to clean-cut or untangle every root. Do the best job you can on the most obvious and essential roots. Pay careful attention to the length of roots. It does the plant no good to bend or stuff them into a hole.

Another aid is to hydrate plants adequately before replanting. The conventional method is to place the plant in its new hole, add some soil, and then fill the hole with water. You can do this in several stages and create a mud puddle of sorts. The Brits call this mudding a plant in. I go one step further and submerge the entire root ball in pure water for several hours, sometimes for a day or more. This gives any root capable of taking up water unimpeded access to it for as long as it takes to plump the leaves. Be careful not to leave the plant in water for so long the roots begin to rot; that would defeat the purpose. Depending on the size of the root ball, you can use buckets, wheelbarrows, cement mixing troughs, or old bath tubs. My personal favorite is a plastic kiddie pool. This has the advantage of being lightweight to transport and wide enough for a large root mass or several plants at once.

Mudding in is a good practice even if you've hydrated the plant in pure water. As the water drains away, the soil gently settles in and around the roots. Roots won't grow into air, and underground air pockets will dry out roots even if the surrounding soil is moist. Use your fingers to poke soil into the middle of the root mass, and don't stamp on the soil around the plant when you're finished. A gentle step or hand press is all that's necessary. Too much weight, especially in mud, will compact the soil and crush the fragile roots.

Water regularly, especially if adequate rain is lacking. Just because you hydrated a plant well at planting doesn't mean it has recovered from the loss or disturbance of roots. That will take several months, sometimes more than a year. Evergreens are especially vulnerable. Deciduous plants lose their leaves and enter a dormant stage in the fall. They need less water over the winter months than evergreens, which lose water through their needles all year. Once the ground freezes, it is difficult for evergreens to replace moisture. If they enter the winter already dehydrated, it can mean severe winter kill. For that reason, it's best not to transplant evergreens beyond August. If you're planting container grown evergreens the date can be extended to mid-September, but water them thoroughly and regularly right up until the ground freezes.

Don't be afraid to transplant. All this might sound intimidating but it's really quite simple, and I often find that homeowners do a better job than professionals. They have a vested interested in the long-term health and well-being of their plants and don't mind spending the extra time the above practices necessitate. Good luck!