If you have not read my blog on Selecting a Tree to Plant, I encourage you to do so as it has information you need to know prior to heading to the nursery to make your purchase. Supposing you have those details in hand, have determined a likely candidate for planting and are now at the nursery. What next? Well, if they have a coffee shop, you may want to sit down…this is going to take a while.
You want to purchase a specimen that has a good chance for survival. Yes, I realize that is another obvious statement. And our prior discussion in selection criteria was supposed to give us the input we needed. However, now I am referring to the actual physical qualities of the individual tree you are considering. The key is to recognize “quality”, which may or may not be obvious. Some clues to help you out are detailed below.
No dead stuff, no disease, no bugs, no dry roots!
If you are seeing dead and broken branches or limbs, signs of disease or bug infestation, pass. There are too many better options. You can tell if a twig or limb is dead if it snaps readily with no green showing in the cambium. An incidental broken twig is not necessarily an issue. If the tree looked like it fell off the truck in transit….pass.
Check out the trunk for injuries. You don’t want to see scuffs, bark missing or indentations that might indicate an injury in the past, such as sunscald.
If you see discoloration on the leaves, such as crisp, brown edges while the rest of the leaf is green this may be a disease, it could be drought stress, it could be a number of things. It may, or may not, be serious. Ask.
If you see bugs on the tree but have no idea what they are…ask. There are beneficial bugs and insects that are great to see. And there are some you don’t want to take home with you.
Before we go any further, let me explain that you generally have three different options of types of trees to buy: bareroot, balled and burlapped (BnB) or container. These are not necessarily offered at all nurseries nor are they all offered for all species. But here is a brief explanation of the three.
These are exactly what they sound like. The roots do not have any dirt surrounding them. They are generally only available in the early spring, at least in my area (reminder I am in Montana). They tend to be smaller in caliper size (trunk diameter), 1 inch or less. Don’t let their small stature discourage you from considering them. It may be enticing to look at the big trees, but restrain your impulse for instant gratification. A smaller specimen will establish faster and easier than a larger one with a better chance of survival. The general guideline is it takes 1 year per inch of caliper for a tree to establish. During that time, the vast amount of their energy should be going into reproducing the roots lost in the digging or planting process. With bareroot trees, very little of the root system has been lost, and the small diameter ensures the establishment time is minimal. Then they are off and running!
Some nurseries don’t carry the variety of bareroot as they do for the other options; call ahead and find out who has what. You have a short time period between when they are delivered to the nursery and when they have to be potted up if they don’t sell quickly, so if you do want to consider a bareroot option, do your research before you head out.When the nursery gets them, they heal them in a medium to keep the roots moist ready for the consumer to purchase. Once you make your selection, a common scenario is the nursery will have a tank of water and shredded paper, sawdust, or other medium to put in a plastic bag to keep the roots moist on your way home. Buy it and take it home. Immediately. Don’t go shopping anywhere else. If you are not going to plant it immediately upon getting home, get it into a tank of water and/or keep the roots moist by rewetting whatever media was used, perhaps even adding more. The tree can soak in a bucket of water overnight. But then get it in the ground. That is critical.
The pros are they are cheaper to purchase, easier to handle and have a much larger root to shoot ratio (which is a good thing).
Balled and Burlapped (BnB)
These are trees of varying sizes that have been field dug with their root system wrapped in burlap and then tied into a ball shape, often with a wire cage to hold things together.
BnB trees tend to be bigger, from 1.5 inches on up. Pay attention to the ratio of root ball to trunk (addressed below). These trees lose a tremendous amount of their roots when dug and balled.
They can come in large sizes, which may be enticing. But remember the caveat about establishment and then also consider how heavy they are. All that soil weighs a ton. You may very likely opt to have these trees delivered and professionally planted.
These are trees also of varying sizes that may have been bareroot trees that didn’t sell and were then potted, or they might have been raised in a container from the get go and potted up as they outgrew the initial container. The container may be plastic, a fibrous material (biodegradable) or fabric.
Possibly the biggest problem with container trees is the potential for circling roots. These are when the roots start circling as they hit the restrictions of the container walls. The problem is they don’t stop circling just because you planted them in the open soil. As the tree grows, they can strangle or “girdle” the trunk.
If you are considering a container tree, ask how long it has been in the container. If it is a small tree, it may have just been potted up from being a bareroot that didn’t sell early in the season. In which case, it will have recently lost a great deal of its roots and be at a very vulnerable stage. If you buy it, you may actually want to let it stay in the container for a while to let it regrow some roots then plant it out in the fall.
If it is a larger tree and has been in the container for more than 2 years, be cautious. I would say the chance of circling roots is pretty good at that point.
Now back to our inspection tour…
You want to select a specimen with good structure. Honestly, that is an entire blog by itself and this one is long enough. I will address what “good structure” means in trees in another post.
If you opt for a bareroot specimen, your selection criteria is pretty straight forward. You will look for no damage as listed above. Since bareroot trees are generally healed in sawdust or a like media, you will be able to see the amount and type of root system to judge health and quantity as you lift your selection out of the mound. If there is something amiss in the root system, such as lack of volume or a significant amount of circling roots, you can replace it (or have an attendant replace it) and keep looking.
For container and BnB trees, reach down and feel the dirt in the container or root ball by poking your fingers down a few inches. Dry roots generally mean dead roots. It does not take long for small diameter roots to dry out and when they do, they start dying. I am sure we have all experienced the container plant we let dry out, watered it and it came back. That’s all good and well (well, actually it’s not a good practice), but when we are looking to purchase a tree to plant, we don’t want something that has already been subjected to drought stress which can have a long lasting detrimental effect. If the tree in question is a balled and burlapped specimen that has been allowed to dry out, heads up. Definitely pass on that one. It can take forever to rewet that root ball and since it took a long time for it to dry out, it is dollars to donuts that tree has suffered significant damage.
The plant should be in the center of the container or root ball.
You want to see an equal amount of the root ball around the stem of the tree. The tree shouldn’t be offset, i.e., closer to one side than another. Figure 1 shows an example. The front tree on the right appears to be situated in the middle of the container while the front tree on the left is offset. There are actually a few issues going on with the tree on the left, so a much better choice would be the front tree on the right.
Root ball appropriate for the tree size
With trees grown in container or balled and burlapped, you want to be sure there are enough roots for it to grow. A general guideline for BnB trees is the diameter of the root ball should be 1 ft for every 1 inch of trunk caliper (diameter) measured approximately 6” above the soil line for trees under 4.5 inches; measured at 12” above the soil line for trees over 4.5 inches in diameter. Again, using Figure 1 as an example, the front tree on the right would be a better choice than the tree on the left in the black container (right behind front tree on the left). The tree on the left behind the front left tree has a larger trunk and a smaller diameter pot.
Depth of root ball
If the root ball diameter is less than 20 inches, its depth should not be less than 65% of the diameter of the ball. If the root ball diameter is over 20 inches, it should not be less than 60% of the diameter of the ball.
Example: If you are looking at a tree with a 1.5” caliper (trunk diameter 6” above the soil line), its root ball should be at least 18 inches in diameter and 12” deep.
Here’s the rub: where exactly is “the soil line”. The soil line is intended to be at the root flare, which is the depth trees should be planted. (Coming soon: Planting a Tree Properly) The top of the soil you see in the container or the top of the burlap may be above that desired spot. In fact, in our experience, many (if not most) cases, the soil is above the appropriate “line”.
The line we start measuring from is at the root flare, which in many cases has been buried during the digging process of balling and burlapping or after many container transplants. You need to find the root flare. This is going to be easier to do with a container tree than a balled and burlapped tree. Feel free to ask a nursery associate to help you.
Now, how do you know what the root flare looks like? Many people confuse the graft (a LOT of trees are grafted) with the root flare. But keep going, you want to see roots that are at least the size of a finger going out and away from the trunk on all sides. Little, tiny roots don’t count. Those may be adventitious roots which grew in response to the tree being buried too deep. And is what will happen at home if you plant it at that depth. Once you find the true root flare, measure from there to the bottom of the ball to determine if there is sufficient depth of root material.
For container trees the criteria on size varies a bit. If you have a 1/2 inch caliper tree that is 4 to 6 ft tall, the minimum root ball diameter should be 12 inches, with a minimum depth of 7 7/8 inches. For every 1/8 inch caliper increase and 2 ft more in height, the minimum root ball diameter goes up an inch and the minimum root ball depth increases by ½ inch. These are definitely broad guidelines, but it gets you in the ballpark.
If you want to get really specific, the American Standard for Nursery Stock, ANSI Z60.1-2014 is available on line for free at the American Horticultural Society website.
Overwhelmed yet? I know. It is a lot to take in. But the more informed you are, the better selection you will make.
Pingback: Common concerns about newly planted trees – MCNEILL'S TREE SERVICE