Most all of us mulch our roses. We do so to keep weeds down, help save water and simply because it looks good. But did you know mulch, when properly applied, can also be an integral part of your rose feeing program? And if not properly applied can actually hinder your rose feeding program? More on how it can hinder later but let’s start with how it helps.
How it helps feed your roses relates back to a previous post we did on Preparing A New Rose Bed. In that post we talked about building a living soil profile through the use of compost, mycorrhizae and other beneficial micro-organisms in the soil. The approach is called “Pro-Biotics”. This is nothing more than increasing your rose’s inherent health through the pro-active use of organics. In other words a complete and balanced natural approach. The post talked about preparing a new rose bed to get everything started off right. But how do we maintain that living soil year in and year out?
In that previous post we mentioned a forest floor is one of the richest soil environments in the world and we want to duplicate that in our garden. It’s rich because every Autumn all the leaves fall and over the next year rot into the soil and become compost. The following Autumn fresh leaves fall and then they also become compost in the ground. This process simply repeats itself year in and year out. And that’s what we want in our gardens.
This is where the two layered mulch approach comes in. And it does nothing more that replicate what Mother Nature has been doing for the forest floor for millions of years.
It starts with two things. A layer of compost and a layer of fresh mulch on top of that. To understand why you need to know one simple fact.
Fresh mulch needs nitrogen to break down. It pulls nitrogen from the air and from the soil beneath it. Therefore if you put fresh mulch on bare ground it actually pulls it from the soil thereby robbing your plants of much needed nitrogen. You get the same thing if you remove all the old mulch first (and we’ve all heard to do this) and then put fresh mulch down on the bare ground.
However once the mulch is broken down the reverse happens. It begins to emit nitrogen down into the soil and into the air.
That is why the first layer should always be compost. It is your nitrogen emitting layer. It emits nitrogen in two directions. First to the ground and secondly into the fresh layer of mulch you put on top of it thereby helping it break down. This means your fresh mulch is no longer taking nitrogen from your plants as it breaks down.
This is also why you should never, ever remove the old mulch because over the season as it breaks down it becomes your nitrogen emitting (compost) layer and the following year fresh mulch can simply go down on top of it. That fresh layer of mulch rots over the season, becomes the “compost” layer and the following year fresh mulch goes right over it. We just keep repeating the process year in and year out. And that is how we duplicate the forest floor. Once you get the process “cooking” you should never have to add additional compost again. Just put fresh mulch over the old mulch. It just keeps feeding your soil and thereby your roses. Now you are being Pro-Biotic.
By now you’ve probably figured out why using mulch improperly actually hinders your rose feeding program. Fresh mulch on bare ground or raking out the old composted mulch steals nitrogen from your plants and does not feed the soil and maintain that living soil we want.
One last thing. Some of you may be thinking if you keep adding fresh mulch your soil level will get higher and higher ever year. No. Not if you have properly created and maintained that living soil profile we talked about in the previous post. It will simply disappear in the soil as all those micro-organisms do their job.
Still not convinced? Think of those majestic redwood trees that are 2000 years old. If every year the soil in the forest where they live got higher and higher they’d be pretty short by now!