After pine tree removal, take care before planting at site
Q: We cut down three pine trees (in two different areas of the yard) that were more than 40 years old. We also had the stumps ground out. I would like to landscape the first area with grass. But where the other tree was removed, we’d like to create a mound and plant some shrubs and small trees there. How should I pre-treat the existing soil in both areas before planting? I am mainly concerned about the shrub-planting site because I don’t want to lose them. We will have topsoil delivered if necessary and I have a compost bin we could use as well. Also, how high should we make the mound to buffer the poor soil?
A: You are smart to consider the soil conditions before you begin to plant in these two sites. If you prepare the planting areas properly, it will definitely increase your chances of success. There are two different ways you can complete this task; one requires more patience and the other requires more work. I’ll outline them each in turn.
The first way is to not plant anything in either site until next spring. Letting the site rest for a season is good for several different reasons. First, the chips of wood left behind by the stump grinding process need time to break down. As the do so, they temporarily steal nitrogen from the soil, making plant growth initially difficult. This is often particularly evident when trying to grow grass in such an area. The grass will often be pale and spindly. Second, since the trees you had removed were pine, the soil there is likely to be quite acidic. Getting it tested through the Penn State Cooperative Extension will serve you well. The test results are likely to tell you that you need to add lime to counter the acidity of the area and additions of lime often take a few months to generate an effective pH change. If it were me, I would test the nearby soil now, add the recommended amount of lime and then retest in the spring (primarily because as the wood chips from the stump break down they too may further acidify the area). And thirdly, this technique is good because the site will probably settle quite a bit. The last thing you want is a big divot in the lawn or a sunken shrub bed with the root balls of the plants sticking out above the soil level.
The second option does require more work, but if you are anxious to get the areas planted, then do this: remove as many of the pine chips as possible from the area. Dig them out and pile them up next to your compost pile or somewhere to the side of the garden. Eventually they will break down (it might take two or three years) but when they do, you can use this compost somewhere in the garden. Once all the chips have been removed from the site, fill the hole with a mixture of topsoil and compost (I prefer a ratio 50/50). Since the area will probably settle, mound it up a little before planting, but without a resting period, how much it settles is a shot in the dark. You could end up with a bit of a divot or a hump in your lawn. This might not be too much of a factor for your shrub bed, but it will be for the grass site. If you go this route, be sure to get a soil test done next spring to check for pH and nutritional content and then adjust it according to their recommendations.
And one more bit of advice: be aware that grinding out a stump does not mean the complete removal of all the tree’s roots. It will be many years until the roots fully decompose. You may find them to be “in the way” of your shrub planting — so have a maul or pickaxe handy as you plant.<