Q: Why so many acorns this year? Did the drought have anything to do with it?
Answer: It's been a big acorn year in my area, too. I think your theory is good -many trees produce a heavy seed crop when they are under stress to produce offspring.
There are a couple other theories, too. Oaks normally have alternating heavy and light acorn seasons. When we have a lot of rain during the spring bloom period, more oak blooms get pollinated so more acorns are produced. Remember, this past spring was very wet for the Richmond area.
Also, since oak blossoms are produced from buds formed the previous year, drought or other stress can affect acorn production the following year. So the good news is, next year's crop should be smaller.
Q: I like to fertilize in September, October and December. I'm not sure what type of fertilizer I should get for the December treatment. What do you suggest?
Answer: Don't wait until December. Apply that final dose of fertilizer this weekend. Though we rarely have frozen ground in December, if we did, lawn fertilizer could run off and get into sensitive water systems.
Most fertilizer companies put out something they call winterizer for the year's final treatment. The last number on the bag represents potash, which gives plants winter hardiness and is good for overall plant health. Look for something with a higher last number in the analysis.
Q: We've done a lot of work on our lawn and it looks great. We have a weed, though, that I call thistle grass coming up in patches. This thistle grass has a thin blade and is a lighter shade of green than the other grass. It also puts out a burr or thistlelike seed. I've used lawn weed killer, and it did nothing. Do you know what it is and how I can get rid of it?
Answer: The thistle grass you describe sounds like nutsedge or nut grass. It is a grass, which explains why your lawn weed killer didn't work.
There is a selective herbicide called halosulfuron-methyl and commonly sold as SedgeHammer which will help manage it and not hurt the fescue.
It is more effective if used during the active growing season between June and August, while the nut grass is actively growing. It can be applied right over the top of established fescue.
Q: I had a grass in my lawn this fall that had an unusual seed head. I took it to a garden center and was told it might be poa annua, but the man wasn't sure.
The cold weather seems to have killed it, but I understand poa annua will come back in the spring. If that's what it was, what can I do about it now?
Answer: It definitely wasn't poa annua, because you saw the seed head in the fall. Poa annua germinates in the fall, and its seed heads don't appear until late winter or early spring.
My guess is you had goosegrass. This is a summer annual that grows all summer long, just like your other grass, but produces its seed in the late summer and fall.
Once the frost kills it, it will never return. All of the seeds it produced, however, will germinate next spring. You don't need to do anything about it now. In early March, be sure to use a pre-emergent crabgrass preventer that is also listed to control goosegrass.