I have gotten a few panicked calls from homeowners afraid their oak trees are dead because they are not leafing out. It is certainly warm enough for leafing out. We had a warm December and a short winter.
In a “normal” year, whatever that is, we experience the soil warming up to 65 degrees at a 4-inch depth around April 15. This year, we hit 65 on March 13, a month ahead of “usual,” and it stayed up until March 21, when a cold front came through. That is still not warm enough long enough for lawns to wake up, but it is definitely warmer earlier.
It’s not the warm temperatures holding back the trees; it’s the timing of rainfall. We had almost two inches of rain Feb. 3 and 4 with another inch Feb. 6 and 7. We had no significant rain since then, except for 0.7 inch March 3 and 4. We had a total of 4.3 inches of rain from Feb. 1 to March 21. The problem is not the amount of rain, but rather its distribution over the last month. The rates of evapotranspiration (water loss from the soil because of evaporation and uptake by plants) is right in line by total quantity, but a rainfall of 2 inches in two days leads to loss of water because of runoff. Not all the rain that fell soaked into the ground. So the trees are slow to come out because there is not enough water available to expand their leaves.
It is March 23 as I write, so I am hoping some Easter rain will have fallen and maybe as you read this, the trees are pushing out new leaves.
Yes, it has been warm, but please resist the temptation to apply weed and feed or even straight fertilizer to your lawn now. We were up above 65 degrees for a week, but soil temps dropped below 65 on March 21-23.
We have not had soil temperature above 65 degrees 4 inches deep for two continuous weeks yet. Maybe we will in early April, but we are not there yet. You can go online and watch the soil temperatures yourself at the UGA weather station website: www.griffin.uga.edu/aemn. Click on the dot by the “h” in Savannah on the state map. Click on “Graph Daily Data” in the first of three columns of weather tools and when the next screen comes up, scroll down to soil temperatures. Change the range of the graph to start on March 1, 2016, to make it easier to track the latest changes.
This is a “teach you to fish” not a “give you a fish” opportunity.
If you have citrus, the first fertilizer application should already be applied. The next application should go on April 15. If your azaleas need to be pruned, prune as soon as possible after they stop blooming, but please do not hedge them. If citrus leaf miner has been a problem (and if you have citrus, leafminer is a problem), the April 15 fertilizer application might be made as an imidacloprid/fertilizer soil drench to help protect new leaves from insects. It has a 50/50 chance of working, but that is far better than we see with topical sprays, which are generally useless against this insect. Don’t pick off infested leaves. If the bug is in there and has not emerged, just squish it in place. The tree will keep the leaves on as long as they export sugar. The tree will shed them if they don’t pull their weight.
This is a good time to run your irrigation system to check for leaks, broken or out-of-position heads and do a can test for each zone so you know how much water is being applied. Use at least 10 straight-sided, flat-bottomed cans. Scatter them randomly across the zone being tested. Run the system. Measure the amount (depth) of water collected in each can. The average is how much is being applied. You can adjust the zone run time to apply half an inch at each irrigation event.
If that is not enough, a good raking of the lawn to get up any matted tree leaves can keep you busy.
Isn’t spring wonderful!