Planting Shrubs and Trees in Piedmont

Planting shrubs and trees in Piedmont is not too much of a challenge. Getting them to live past a summer or two can be quite a challenge. This article will give you some ideas to make that a little easier to accomplish.

The nursery industry has typically always recommended amending the soil placed back in the planting hole. A study was published a while back that reported that this practice had no positive impact on the tree size or health at maturity. I don’t argue with that conclusion as far as it goes. But to get a shrub or tree through the critical first year or two, amending the soil is a big help if done correctly.  A problem that can occur is that the amended planting hole turns into a restricting bowl that discourages the plant’s roots from growing outward into the native soil. This occurs because of the sudden transition from the good soft amended soil to the hard clay soil that is native to this area. Digging the hole large enough that the roots have room to grow before encountered this transition in the soil can minimize this problem. This transition should be minimized by leaving a rough edge around the hole (use the shovel to rough up the sides of the hole).  Keeping the soil moist at the root growing depth will allow the roots to penetrate this transition as well. The amendments will assist in this goal by allowing the water to penetrate down to a useful depth. These amendments provide the nutrients, aeration, and good drainage to get the plant off to a good start.  Then as the years go by, you will have the opportunity to improve the surrounding soil with amendments and mulching.

The guidelines for a successful planting begin with digging the hole large enough in diameter to allow the roots to spread out easily without encountering the edge of the planting hole. Dig the hole only deep enough to allow the plant to sit at the recommended depth. This is usually at the same depth that it was growing previously. Amend the soil with compost or other well-rotted organic matter. Organic matter that is still fresh can heat up and kill the plant roots. It can also result in nitrogen starvation due to the biological processes involved in breaking down the fresh organic matter. A good mixture would be one-third native soil, one-third compost, and one-third sand. These amendments provide the nutrients, aeration, and good drainage.  The amendments allow irrigation or rain water to soak into the soil in a reasonable quick manner. This is very important during the heat of the summer when watering needs to occur as often as twice a week or more. Having a raised ring of soil around the planting hole also helps hold the water to allow it to soak in rather that running off. Having the entire planting area raised four to six inches above the surrounding soil can be a good idea. This is most useful with plants that are very sensitive to poor drainage around the roots or when you know that you will be improving the surrounding area with additional amending of organic matter.

The plant should be placed in the planting hole and the roots gently spread out in all directions. Any broken roots or branches should be trimmed off. Exposure of the bare roots to sun and wind should be minimized. It is a good idea to have soaked the roots of bare root plants for an hour or so prior to planting time. The amended soil is placed back in the planting hole. It should be carefully filled in around the roots to minimize any air cavities around the roots. The soil should be firmed as it is being placed back in the hole. Once the hole is filled, the plant should be watered in well. Additional soil will likely need to be added after this initial watering. If the plant has a good balance of roots to upper trunk mass, staking is not needed. This is also aided with the careful firming of the soil during the planting. If the plant does not appear to be stable without staking, then two or three steel posts or stakes around the plant can be used.  Be sure to protect the plant’s trunk with something such as a short piece of old garden hose where the support wires goes around the plant. It is best to remove these supports after a year or so that the plant can become accustomed to supporting itself. Wintertime is probably the best time to remove the supports due to lack of foliage at this time of the year.

An important final step is to add mulch to the planting area. This serves several purposes. It will suppress weed and grass growth around the new plant. It will help retain more even moisture levels between watering. It shades the soil and therefore keeps the soil cooler. The bare soil can get very hot during the summer and most plants can not handle this. Mulch is even useful during the winter. Winters here can be dry, so the mulch helps retain the moisture during this time. It also moderates the soil temperature swings during this time of year. If the mulch is organic matter such as shredded leaves, horse stable material, or wood chips, it will slowly break down and fertilize the plant.  A problem can occur if the mulch material is too fine textured. The material can mat down and prevent good penetration of water. This should be avoided. Mulch should not be laid all the way up to the trunk of the plant. A couple of inches of clear area should be left immediately adjacent to the trunk so that mice are less likely to damage the plant. The use of plastic for mulch is usually not a good idea. It tends to cause the soil to become waterlogged and sour due to lack of good air circulation.  Other mulch materials such as gravel are helpful but not as good as organic matter.

This should give you a head start on learning how to plant shrubs or trees in the Piedmont area. If you have questions about your specific situation, or suggestions for a future article, feel free to contact me.

Thomas Kiene,  (405) 373-2974,  ThomasRebel@pldi.net (A founding member of the Piedmont Farmers Market).