what kind of mulch should I use?

I'm talking summer mulch here, not the kind used for insulating tender plants over the winter.

Mulching your garden will help to conserve water and suppress weeds - definately a sustainable choice for both the environment and your enjoyment of your yard!  Basically, there are 2 types - the permanent kind and the kind that must be replaced every few years.  But wait, don't make a decision yet...

Permanent: rocks, gravel, shale etc.  These mulches do the job.  Pea gravel and other gravels are trendy right now and look especially nice in a xeriscape garden (lots of drought-tolerant plants that like the heat absorbed by the rocks).  However, there are some major cons:

• Look at all the dust, soil and dead plant material that must be cleaned off every year to keep it looking good.  If you don't, then eventually there will be enough matter there for weed seeds to take hold and you've defeated the purpose of the mulch.  Somebody mulched my whole yard with red shale about 20 years ago, and I am still cursing them.  It's not in style anymore and I spent my first summer in this house digging it all up because it was dirty, dusty, and I wanted more room for plants.  Don't put down a permanent mulch unless you're sure you won't want to change it... ever.

Non-permanent: bark, shredded bark, compost, etc.  While these types of mulches do need to be replaced (the smaller the pieces, the faster it will break down), they also do the job of fertilizing the soil while they decompose.  So voila, you've also fertilized your garden the way nature intended!  However, barks break down slowly and also draws some nitrogen out of the soil for the decomposition process, so it is still recommended to add compost (or other organic amendment) as fertilizer.  That means you have to rake off the bark mulch, topdress with compost, and add the bark back on top again.  Ugh.  Why not just use compost?  It is easy to apply, you can make it yourself (although I always need more) and it looks great - like a professionally tended garden without a weed in sight!  Well, at least for a while...

So depending on the style of your garden, your taste and your willingness to spend the time, the final decision is up to you.  This year I am using shredded bark mulch for the pathways in my garden (because I don't have to worry about fertilizing them) and compost everywhere else, including my small patch of lawn. It's a bit of work in spring to spread the mulch (but of course this is when I am most keen to be doing major garden work), and then your work is minimized for the rest of the season.  And if you don't like it, you can change it next year - just don't add 3" of red shale... please!! 

Comments

[Amy]

If only I had enough compost! I'll get there someday - I just have to be patient. I wish I could find a nice local farmer with piles of rotted manure ready for my utility trailer :) I thought about gravel mulch once, but can't imagine trying to clean the debris off all the time, and my soil needs amending.

[Doug Wagner]

I hear you on the red shale. Awful stuff to work with or remove (it is sharp, cuts up your gloves, difficult to shovel) and after a few years it breaks down to sand and allows weeds to grow.

I like the bark mulch so far. We get a lot of weed seeds blowing in so not sure if just compost will work. About 30 yards of compost and 50 of mulch to spread so good thing the season is starting out early.

Happy gardening.

[Janice Miller-Young]

Hi Doug,
Wow, thats a lot of spreading youve got to do! 
Youre right, the bark mulch will keep weeds down better than compost.  I guess it depends on your specific needs.  My garden is mostly perennials that get big enough later in the season that they keep the weeds down just by shading the soil.  I still do a little weeding but not a lot.
Happy spreading,
Cheers,
Janice

[Sean]

Hi Janice,

I'm looking to get rid of a lot of red shale here in Calgary. Do I have any options other than trucking it all off to the landfill? I'd love to be able to try and sell it, but it's fairly mixed with mulch and debris.

[Julie]

I have used red shale to fill the bottoms of large planters. Seems to be good for drainage.