Getting a lot of calls over the last week about leaf scorching and some die-back on young trees. This is something we see every year beginning in late May/early June and is related to the inability of the relatively small root system on young trees trying to support such vigorous and rapid growth of the shoots. It shows up this time of year because we get a shift in temperature, which means soils heat up and water demand increases.
I wrote more extensively about why this happens in an article on pecan root systems in the April issue of the Pecan Grower magazine so check that out if you have a copy. If not, you can get a copy by contacting the GA Pecan Growers Association.
This scorching/die-back problem in young trees (usually 3-4 years and under) and simply poor vigor in newly planted trees are manifestations of this same problem (inadequate or damaged root systems) in different situations. Damage to the cambium layer of the tree through mechanical damage or freeze injury can lead to similar symptoms.
In all cases the fastest way to remedy the problem is to cut back some of the shoot growth and relieve some of the pressure on the root system. Make sure you maintain consistent soil moisture. Water regularly (every other day is best) with deep waterings. Long run times every other day are better than short run times daily because you water deeper and allow the root system to develop deeper through the soil profile. In addition to providing soil moisture this also helps to keep the soil from getting too hot (soil temps >95 degrees inhibit root growth).
Another thing to consider for future plantings is that you will get more vigorous and healthy first year growth less leaf scorching/die-back if you plant before March. Earlier planted trees have a chance begin some root establishment prior to bud-break. I’ve had this theory for a long time based on what I’ve seen in the field over the years but we started a study on planting date this year and the results are striking from a visual standpoint (see below).
Pawnee tree planted mid-March
Pawnee Tree planted early February