Poor spring green-up in bermudagrass is usually a combination of several causes, plus one "straw that broke the camel's back."
Usually, the biggest issue is the soil test K values are marginal. In the subsoil it is almost certainly really low. When this is combined with a low soil pH -- which even for bermudagrass should be > 6.3 for best results -- the plant becomes extremely stressed.
K is critical to plant vigor, stolon and rhizome health, drought tolerance, winterhardiness (which should also be thought of as spring emergence), and disease resistance.
Given the cadre of problems we've had in the past several years -- drought, late freezes, high pest pressure, and greater disease incidence -- it is a wonder that the bermudagrass growing in even extremely fertile sites isn't having problems.
So, really, it shouldn't be a surprise that bermudagrass is suffering in less fertile sites. But it is a surprise, even to those of us who see this all the time.
A common situation is that “the straw that broke the camel’s back” this year was a dormant spray on the bermudagrass -- only the bermudagrass wasn’t very dormant.
This additional stress, when it is in its most vulnerable state -- i.e. breaking of winter dormancy -- is enough to push it over the edge. Burning it back with a herbicide at that stage, even one like paraquat that doesn't translocate, will sting bermudagrass severely.
Research in the turf world suggests that using just 1 pt of glyphosate on bermudagrass during a "dormant spray" can cause severe spring stunting if the bermudagrass has >10 percent green-up at the time of application.
However, let me emphasize: The latter is just the straw that broke the camel's back. Had the soil fertility been in good shape, the lack of spring green-up would have been very short term.
If you have a stand that has not yet greened up, you may be asking yourself, "Well, what do I do now?"
The only reasonable thing to do now is wait. If the pH is off, add the recommended lime and then wait. If it is needed, the sooner the lime goes out, the better.
If the bermudagrass has begun to show some signs of green-up, address the soil pH and K deficiencies. Put out K at a 1:1 ratio with the N.
No shortcuts. No excuses. K is a heck of a lot cheaper than re-sprigging.
If the stand is still struggling to emerge -- i.e. little or no signs of emergence -- begin making plans to replant or rotate out of bermudagrass for a year or two. There is a very real possibility that this stand is now dead.
You can put it to a little bit of a test by digging a few plants and looking for green (or at least white) tissue at the plant base/crown. If it is brown or decomposing, that plant will not recover.
If more than 50 percent of the plants you dig aren't going to recover... well, the good news is you’re going to get a chance to incorporate your lime and fertilizer.
If it doesn't green up by the end of April, then it is dead. Sorry, there's nothing for it. FG
—From Georgia Forages
