Well, probably very little. It may set some weed emergence back a little. What I really wanted to talk about though, is something we face every spring. When is the best time to do spring cleanup and prune our bushes, roses, grasses, ect? It seems like our main purpose for doing it early is looks, (keeping up with the Jones?)
Let’s talk about the negative. Often times, there is no though given, to the health of the plant. Being good stewards and getting it done first, isn’t always being a good steward. There is a high likelihood that a high percentage of Knockout roses, that were pruned early will be “damaged.” Also, ornamental grasses can be susceptible to late freezes after they are cut off. I have one job where we were under pressure, from the homeowner, to get it done early. We got a late freeze and a lot of the Adagio Maiden Grasses died. Someone recently told me, Knockout Roses will freeze back from the prune location, the same amount that they freeze back during the winter. So what they were saying, is if they were not pruned before a late freeze, there would be almost no damage, they wouldn’t freeze back anymore than they already had for the winter. But if they get pruned early and we get a hard late freeze, they may freeze back another winters worth with one late freeze.
Often times while doing spring cleanups, I am amazed at the tender young shoots that are growing up underneath that (unsightly) trash, last year’s vegetation, last Falls leaves that blew in, ect. When we rake and blow that off, I think it must feel like someone jerked the covers off, early in the morning, when you are snug in a warm bed. That unsightly trash, is a protector against late spring freezes.
Am I making my point clear? Sometimes, there is quite a negative plant health aspect, that comes with peer pressure.
We landscapers aren’t guilt free either. If we can get Spring Cleanups done early , it frees our schedule up later when other things break loose, like first time mowing grass and applying crabgrass preventer ect.
To summarize, I am not against early spring cleanups. I am just opening our eyes, to a largely overlooked, negative effect, of getting too in a hurry.