Buying and Planting a Potted Tree
When thinking about purchasing a tree, people often picture a tree with its roots balled up and wrapped up in burlap. This “balled and burlapped” (B&B) option is typically reserved for larger trees that require professional installation due to their size and weight. For the do-it-yourselfer, a great option is buying potted trees or “containerized” trees.
Many of the principles for buying and planting B&B and potted trees are basically the same, but there are some subtle differences you need to consider. Potted trees come in a variety of container sizes. The largest container you’ll typically see is a #25 and that means it’s a 25 gallon pot. From there they step down by 5 gallons (#20, #15, #10). You’ll also find smaller trees and shrubs in #3, #5 and #7 containers.
The bigger the pot, the bigger the tree will be at the time of purchase, but the trunk size or the overall height of the tree will vary by species. For example, an Autumn Blaze Maple in a #20 pot will run about 10 feet tall with a trunk measuring about one and a half inches in diameter, while a Black Hills Spruce in a #20 container will stand about 4-5 feet tall.
Potted trees are grown in a “soil-less” potting mix which drains well but also holds moisture quite well. It also makes handling the tree easier because it’s lighter than soil. The container itself makes handling and transporting the tree easier as well while protecting the roots. When moving your tree always handle it by grabbing the pot, do not drag the tree by the trunk or lift it from the branches.
Digging the Proper Sized Hole
Your first step is to find the “root flare” of the tree. The root flare is where the trunk is connected to the roots. Sometimes, the flare will be perfectly placed slightly above the soil line, but more often than not, you will find it embedded in the soil, often times up to several inches deep. It is imperative that you find the depth of the root flare before you ever dig your hole, as that depth is directly related to the depth of the hole that you will need to dig. Remove your tree from the container and use a shovel to gently remove the excess soil to expose the root flare. Once you find the depth of the root flare, measure from the bottom of the root ball to the top of that root flare. This is the depth that you should dig your hole, or perhaps even 1 or 2 inches shallower, but do not dig any deeper. You want the bottom of the hole to be undisturbed, so that the tree does not settle after planting. The planting hole should be wider than the root ball with enough room to work comfortably – approximately 2 times the width of the root ball.
Planting your Potted Tree
You’ll be planting your potted tree in a heavier soil than the potting mix it had been growing in the container, so you need to “wean” the trees from their pots into that surrounding soil. We recommend you amend the planting soil with some sort of organic matter. There are all types of amendments that you can use. If you make your own compost, use it, however if you choose to purchase an amendment, you will want to use about 1/3 peat moss or mushroom compost to 2/3 of your original soil. Keep in mind that we want to amend the soil, not replace it. Your goal is to wean the roots from the really well drained potting medium, out into the firmer original soil. When you add organic matter to soil, you will want to mix it up evenly, don't layer it. It is easiest to do this either on a tarp, or in a wheelbarrow. Blend up your soil/amendment mix and have it set aside to use when back filling. When you are working with your soil, break up any chunks of soil and try to have a nice loose, fluffy mix to use when you put it back in around the root ball. Having lots of chunks in your mix will allow air pockets to form in the soil. Roots can't take hold well when there are lots of air pockets. Having a loose mix will insure good soil contact and healthy roots.
Now is the time to get that tree into the ground. Double check the depth one more time confirm your soil has been properly blended and ready to go. Since you removed the container in order to expose the root flare, you can simply set the tree in the bottom of the hole at this time. The roots may have already begun to literally circle the root ball. If so, you will want to straighten or loosen any of these roots to prevent any future girdling.
After getting the tree set in the bottom of the hole and before back filling, this is the time to add any additional planting additives such as MYKE or Root Stimulator, if you choose. Add back a few inches of soil to help stabilize the root ball. As you add soil back a few inches at a time, soak each bit with water to ensure that the root ball is saturated, the surrounding soil is saturated and the soil that you are back filling with is saturated. It is ok to have a wet, swampy mess at this time as it will push out any air pockets that might be in the soil, as well as make sure that the soil settles well and makes good contact with the root ball. After filling the hole completely, top it off with a 2-3” deep ring of mulch. Mulch will help to keep the weeds and grass away from the trunk of the tree, and it helps to retain the moisture that you have added. Do not allow the mulch to touch the trunk of the tree. Your mulch ring should end up the shape of a flattened doughnut; not a volcano. We only recommend that you stake the tree if it is absolutely necessary, keeping the support low on the trunk to allow the tree to bend in the wind. This will ensure that the tree will remain strong as it grows.
It is hard to put a number on how many gallons of water a young tree will use and how much should be applied. Different soils, weather, trees, etc, prevent us from giving a specific answer. Our recommendation is to water absolutely thoroughly, let the soil dry out slightly and then thoroughly water again. Regardless of the soil that these trees are planted in, if you wait about 1 week (5-7 days) between watering, as long as you are thoroughly saturating the soil when you water, should be sufficient. Of course there are always exceptions, for instance, birch (really thirsty) may need more, but ALWAYS check the moisture in the soil before watering! If the soil is moist, wait to water and check again tomorrow. We have found that over watering is the number one reason that trees fail in the first year. Under-watering can usually be corrected if caught quick enough. However once a tree's roots have started to rot from too much water, it is unlikely that they will recover. If the soil is wet and the leaves are wilting, it is likely that the tree has been over watered and needs to be allowed to dry out. Check your soil often, every 2-3 days and water when it becomes dry a few inches down. Use your hands and eyes to check the moisture. Using a watering bag when you plant young trees, has proven to be a valuable tool that might make it easier to water your trees. These bags are capable of holding 15-20 gallons (even if the planting hole only holds 10 gallons, the excess runs off and it is impossible to over water if used properly) and allows the water to be applied slowly to the root zone, letting it to soak in completely over the course of a few hours, rather than running off. Simply set them up at the base of the tree, fill them with water and walk away. Re-filling this bag about once a week should be sufficient in keeping your young tree going regardless of dryer weather.
Always keep in mind that if you have any questions about your trees or their planting, please feel free to call us here at Gertens. We have several staff members that are here to help, just ask!