In much of my service area, here in the mid-Atlantic region, there are many “old growth” trees.  The term old growth is kind of an arborist term.  It usually refers to a large stand of trees or even a stand of trees as big as a forest, trees that have remained relatively undisturbed.  In this case, what I mean by old growth trees are old and large trees in an urban or suburban landscape.  Trees that have been there for a long time and have a rather large trunk radius at chest height.  

I’m a big guy, six and a half feet tall.  If I cannot wrap my arms completely around the trunk of a tree, that’s a big tree.  And logic dictates that a tree with a trunk that size, or larger, is a fairly old tree.  On my property I have 18 old growth trees.  My calculations on their age range from around 150 to 175 years old – at least – maybe even older.  I imagine where my house was built used to be a forest.  I have written other blog posts about tree care (e.g. “Tree Care for Turfgrass Warriors”) but in this blog post I’m going to focus on what to do about all those leaves that come down in the fall.  Should you remove the leaves?  What can you do besides removal?  And, what do those leaves do to the soil if they are not removed?

The short answer to the first question is: YES.  If you want quality turf, you need to do SOMETHING about those leaves.  Turf needs sunlight to thrive.  Turfgrass leaves must be exposed to sunlight to assist in the process of photosynthesis.  Photosynthesis is the process where light energy is transformed into chemical energy.  Without sunlight, plants cannot produce chlorophyll.  Chlorophyll is the by-product of the plant by taking sunlight and making energy for the plant to grow.  For good and healthy turf, you need several hours (5 to 8) of sunlight each day.

You ever put down a tarp or something else over your turf for a couple days?  Did you notice that it started to turn yellow or just wilt in general?  That’s because you blocked the sun.  Fallen leaves will have the same effect as laying out a huge tarp. 

One thing you should consider is removing all the leaves entirely.  I get lots and lots and lots of leaves in my yard.  If you have this affliction, I feel your pain.  I know raking by hand is tough, especially if you have a large turf area.  Blowing them can be difficult as well.  I’ve tried using a Billy Goat, like a big lawn vacuum.  The bag for that thing would fill up in seconds.  I also have a tow behind lawn sweeper.  I spend more time emptying that thing than actually dragging it around to sweep up the leaves.  Fall leaves can be a tough mission to accomplish – especially if you are an army of one.

I’ve inserted a picture that shows one of my sub-contractors (a local landscape company near Mount Vernon, VA – Green Blades) removing my leaves.  For a flat fee, sometimes they show up two or three times during the fall leaf drop period.  What they usually do is blow the leaves onto a huge tarp and drag the tarp to the front curb.  Many municipalities (or other units of government) have leaf pick up from the curb.  I just pay the few extra dollars to have the landscape company haul away the leaves each time.  The landscape company uses the same equipment as the government for hauling away the leaves.  It is a big vacuum that is towed behind a large truck.  The workers rake the leaves into this huge suction tube about 20 inches in diameter.  I like that much better.  I drink coffee and supervise.

Complete leaf removal – however you do it – is my first recommendation.  Listen, you can’t do your other lawn and landscape winterization missions (dethatching, fertilizing, aerating, bed mulching, etc.) if you have a serious layer of leaves in your yard.  And, you may run out of time for your other winterization missions if you are working leaves all the time.  Get the leaves collected; and get them gone.  That’s what I say.

Another course of action answers the second question.  That course of action is “chopping up” or “mulching” those leaves.  In most cases, for the standard homeowner, that means running over the leaves with your mower.  But, think about that for a second.  If you have a fairly deep or thick layer of fallen leaves, having them all chopped up does not necessarily alleviate the sunlight exposure issue I discussed earlier.  Remember, you are trying to expose your turfgrass to more sunlight, not just cover it up again with leaves that are in smaller chunks (and those smaller bits would be even more difficult to manage or remove).

In addition, its hard to say at what “amount” or “depth” of leaves would it be disadvantageous to chop them up.  I think you just got to eyeball it.  I can’t really tell you, “Well, newly fallen leaves (and what type of tree?) over a depth of X inches should not be mulched.”  Sorry.  You might have to do your own analysis on that one.

Providing organic material to your lawn, ornamental beds and soil is a good thing.  Having a good amount of organic material in your soil increases aeration and soil tilth.  Mulching leaves certainly assists in accomplishing that mission.  But, are the mulched leaves going to just be left on the surface?  How do you plan to integrate the mulched leaves into the soil?  More questions to think about.

There are other considerations too.  Certain leaves, from certain cultivars of trees, can alter the pH of your soil.  The big, old growth trees on my property are two different kinds of oak.  Oak trees make the soil acidic just by being there – and the leaves make the soil even more acidic.  Generally speaking, oak tree leaves have a pH of 4.3 to 5.3.  That is way below what is desired for most turfgrass soil.  Pine needles, for example, can also increase the acidity of soil.  So, this too may be an argument for complete and total leaf removal. 

If you really have your heart set on mulching your leaves, please make sure you have a mulching attachment and/or mulching blades on your mower.  Mulching mowers chop up leaves (turfgrass clippings, just about everything) more finely.  It basically holds things inside the mower deck longer and chops the stuff up more.  I’ve said this a million times:  A mulching mower is environmentally responsible.  It saves you additional fertilizer applications, improves soil tilth and reduces thatch.  It allows your grass clippings to decompose faster.  Use a mulching mower all the time, every time you mow – not just for your leaves.

And don’t forget about sharp blades.  Can’t say that enough either.  Getting your blades sharpened is okay.  Hopefully, you or the guy doing the sharpening know how to do it correctly.  Unbalanced blades can be dangerous, damaging equipment or even a nearby person.  For @ $70.00 (including shipping) I get new blades every year.  I throw the old blades in the recycling bin.  My mower has a 42 inch deck.  It uses two blades.  I get two sets of blades each year.  I put a new set of blades on the mower at the beginning of the spring mowing season and a put another new set of blades on at the beginning of the fall mowing season.

Hey, I get my leaves removed.  But, guess what I do when I mow in between the leaf removal guys visits?  I mulch my leaves.  Sometimes its not many leaves, but they get chewed up regardless. 

Okay.  I’m gonna wrap this up.  If you live in an area where fall leaves are pretty significant, I highly recommend you get rid of them – anyway you can.  If you are going to mulch them, consider some of my points here.  I think there may also be a happy medium and cost effective way to do a little of both – removal and mulching.  That would be an excellent exercise in negotiation with a local landscape company.  They remove some; you handle the rest.  A lot of it also depends on timing, the climate during a particular fall, etc.

Also, look on my blog post, “Leadership by Example”.  I will post some more recent photos of my lawn from this past fall, the fall of 2015.  You will not see many leaves.  But, you may see a few that have been chopped up.

Get rid of your leaves.  I can guide you.