A Mulch Primer

If I could pick just one thing that you could do to improve your green thumb, it would be to mulch.  Mulch more and mulch more often, using the right kind of mulch.  Say that three times real fast.

I think of mulch as tucking the plants in for the season.  Whenever you plant any  perennial flower, tree, or shrub; you want to have enough mulch to spread 2-4” thick all the way to the width of the branch canopy.  Wider is even better, that way over time it builds up the soil around your foundation plants so that you can plant in it later.  There is no such thing as too wide.  Do you really need that grass?

Most likely you’ll be picking up your mulch when it’s spring planting time, which is right when the suppliers are crazy busy and they just want to get your order done and move on to the next.

My first piece of advice is, if you have the space, to get stocked up before then; say in January or February. That is when supplies are high and you will have a much easier time getting your questions asked.  You can also find better deals at that pont, especially if you bring cash.  Suppliers welcome the revenue during the slow times, and it pays to build a relationship with a good local source.

Second, get more.  Think you need 2 yards, get 5.  You will use it.  Put it in thick, your plants deserve it.  Assuming you are getting it delivered, the cost of delivery is usually about the price of a yard of mulch, so you don’t want them coming out twice.

The Benefits of Mulching

This is specific to our compact heavy clay soil in the Asheville area.  If you are lucky enough to be able to dig with a shovel and not a pick mattock like me, it may not apply to you so much, but I’d still mulch just the same.

  • Keeps the weeds down.  You knew this of course, but it’s worth mentioning.  You get a lot less weeds when you mulch.  Not zero-there are a lot of stubborn weeds.  If you want more thorough control it’s a good idea to use a pre-emergent weed preventer like Preen right after mulching and before your plants leaf out.
  • Regulates moisture.  I find that with a good mulch watering is almost never needed with plants in the ground.  Sometimes I can’t help myself and go to water in the middle of summer, only to get under the mulch and find the soil plenty damp despite days of no rain.  By the way, it’s a good idea to do this- check under your mulch, because over watering is a real plant killer.
  • Softens soil.  This is the real biggie.  Lets face it, gardening can be a lot of hard work.  Whenever an opportunity presents itself to slack, I’m going to take it.  So rather than work the soil or tilling it up, I topdress with mulch instead.  Is this as good in the short term?  Probably not, but over time that mulch breaks down and softens that heavy clay soil up. I’ve had great success planting in almost straight clay with this method.  And I mean straight clay.
  • Amends soil.  Have you ever seen those bags of soil conditioner at the box stores?  Or most “topsoil” for that matter?  Those bags, in one form or another, are mostly composted (broken down) mulch.  Rather than buying more bags of overpriced mulch, I just throw a shovelful of whatever mulch I have on hand into the hole when I break up the clay.  Good drainage is our biggest challenge in this area, and that mulch will help break things up a little.  Keep in mind that it’s best to use a smaller grind bark mulch for this and not big pieces of tree.

Types of Mulch

  • Grind size:  Basically the more times it’s been ground, the faster it breaks down.  You don’t necessarily want it breaking down fast, that will depend on what you are using it for.  If I have a bank to cover and forget I want the cheapest single grind I can find.  If it’s for my tomato beds I’d want something much finer, say triple grind, or fines.
  • Bark or whole tree:  In general a bark mulch is preferred for your beds and most landscaping purposes, but when times are tight it’s better to go with the cheaper whole tree than nothing at all.  Again, for banks and areas you want to forget about and keep tidy, there is no reason not to save the cash and get the whole tree.  Arborist wood chips are another option for those spots, often available for free from the county.
  • Type of tree:  Around here there are basically two kinds of wood used;  hardwood or pine.  Unless you just like a particular wood, the important things are grind size and if it’s bark or whole tree.

If I were to choose the best all purpose mulch to have on hand it would be double ground hardwood bark.  Bark being the key term here.  The bark breaks down quickly (you want that if you have really heavy clay), and the bark is nutrient rich and fluffy.

Nuggets, dyed mulch, wood chips:  All these are specialized items, usually at a premium price.  These have their place if you have the need for a certain look or aren’t planning on planting much in those beds for the season.  For most gardeners these products won’t be of much interest.

UPDATE 5/3/21:  I have always used pine bark for my perennial beds and recently had a master gardener friend tell me she thought hardwood bark was better because it doesn’t acidify the soil as much.  I think she may be right on that one, so I stand corrected!  If you do use pine, it may be a good idea to sprinkle some pelleted lime over those beds every other year or so.

That said, all bark (pine or hardwood) is the way to go for your nicer areas.  I’d suggest going to see Matt at The Longest Yard, and stock up now, all the construction happening has mulch at great prices.