This week we are going to continue to look at the best type of mulch called “Native Mulch”. 

Native Mulch (fresh ground) – This mulch comes directly out of the grinder. It does not have any processing or screening on it. It tends to be inexpensive and useful in special applications. As in all native mulches it is a mix of whatever species came into the mulch/composting recycling facility. 

Double Ground Native – Often mulch companies will re-grind the native mulch to a finer texture which is commonly called “double ground”. This may be available as “fresh ground” or aged. As the double ground native mulch is allowed to sit in large piles it begins to compost. Over the next few weeks it gradually becomes darker and after a few weeks it is a medium brown color with a nice fibrous texture that sets up well and resists washing out. 

Due to the drought of 2011 and 2012 we have received very large amounts of dead tree material from the cleanup. As a result we have added double ground mulches both fresh and aged to our product line this year. I personally like to test and use all the products we produce or sell, so I have first hand information on how they perform. So in January I used both the fresh ground and the aged double ground native on my own yard and this is what I have learned. Double ground is not composted hence it has a higher carbon to nitrogen ratio than our premium composted native mulch. To ensure there was not a nitrogen tie-up issue I applied MicroLife 6-2-4 organic fertilizer first to the beds before putting the mulch down. I then applied 2-3″ of mulch depending on the plant species and the amount of mulch left over from the previous year. Note: I did a small area with our composted native mulch side by side so I would have a comparison (see picture below). 

A few months have passed and this is what I have learned. Pros: It does a very good job of keeping the soil cool and moist, it has decomposed rapidly into humus rich layer, the earthworms have multiplied and grown very fat in the mulch layer, all plants are doing great and growing like weeds (I am having to do a lot of pruning to keep them in check). Cons: Since the mulch is not composted (no heat to kill the weed seeds) I have had numerous trees sprout in the mulch (many oaks species, pecans, etc.) that I have had to pull out and there have been a few weeds also that would not be in the composted mulch. I have also had many species of beautiful mushrooms (fruiting spores of beneficial fungus) of various sizes shapes and colors that appeared after several rains this spring helping the mulch to break down and release the nutrients it contains. 

The picture below shows the color difference between the aged double ground native mulch and the composted native mulch in an area that I will be reworking this summer. 

If one is not in a hurry, fresh ground native mulch is one of the best ways to naturally break up heavy clay soils and suppress weeds. To suppress weeds it is often applied 4-6 inches thick and sometimes rolled or watered down (weight). The mulch smothers the existing plants essentially killing them. This mulch becomes very active biologically because the microbes are working, and they will use the nitrogen stored in the dead and dying weeds to help break down the mulch. The microbes will also break apart clay particles creating a looser soil. 

Different types of native mulch are also used for erosion control, soil improvement, garden paths, land reclamation, filtration of storm water runoff, and any other application where large volumes are required and cost is an issue.