We plant a lot of trees every year and we sell and plant many trees at the Landscape Shoppe. A common mistake that I see happen is that many, when planting trees, just don’t put the effort into the process…. Yes, it can be a big effort! I regularly consult on trees that have died or are sick and unhealthy. 90% of the time it goes back to the original planting process. The clay soils in our area will grow plants and grass just fine but they need to be amended. I typically see a plant installed in the same size hole as the root ball or container size that it came out of. My rule for my folks is 2 by 3. Twice as deep and 3 times as wide is how we plant trees. You're probably thinking right now, "Wow that is a lot of effort especially for a larger caliper tree." You're correct! But a properly planted and staked tree will develop strong and healthy roots leading to many years of Happy Tree and Happy Owner.
Planting - Start with the onsite soil, if it is very hard or rocky this is fine. Use a pick or a very hardy shovel to dig out the hole 3 times as wide and twice as deep. Once you have the hole dug out scarify the bottom of the hole using a shovel to make grooves in the bottom and sides. Next use the onsite soil that you dug out of the ground and mix a soil amendment with the onsite soil breaking up the clay. If the soil is rocky not a problem. Roots like rocks it gives them space to move out into the soil that is rocky. In fact we will routinely put a layer of round rock in the bottom of the hole if the tree is in a very wet area with low drainage.
Soil amendments - In my opinion it really doesn’t matter what you use, the goal is to give the onsite soil some breathing room for lack of better word. I recommend aged bark, hemlock or fir. Compost and potting soil are great but a little more expensive. The best product would be peat moss mixed with a little aged bark. Be careful about blending a too concentrated soil amendment or too woody soil amendment or too Hot of an amendment like non broken down manure or grass clippings. Mix about 15% to 20% amendments into the onsite soil using a shovel by turning it over and over until thoroughly mixed. Next build up the soil in the middle as the hole will be twice as deep as the root ball. Compact this soil with your foot so that it is very firm, place the tree or shrub on top of the backfilled soil medium and check to make sure that the crown is not going to set too low. You can do this by using a stick or the shovel to measure that the edge of the hole is level with the tree crown, you will be better off planting the tree to high rather than too low so this is important. Next finish the back fill and very importantly compact the soil very well with your foot so that it secures the root ball for staking.
Staking – Very important, especially with trees. Always stake and tie a tree for as long as you can maintain the tree or until you feel that it is very well rooted. This takes at least 2 seasons and it also depends on the type of tree and its growth habits, soil down below, and a host of other reasons (whole other subject )….. Next blog.
We usually use 2x2 wood stakes as eventually they will decompose in the ground. Metal T Posts can be used but after a year or 2 they can be hard to get out of the ground.
There are many other factors that lead to the demise of plants and trees and there is a lot of info obviously on the web, but there are also a lot of myths out there and misinformation out there so I will continue to pass on my learned experience. Hopefully this helps.