Bark-mulch is the stuff that clever gardeners spread over their flower beds. As the name suggests it is crushed pieces of bark.
Principly it is just woody waste from the sawmill which is generated in large quantities during peeling of the stems. And large quantities of it are also used in the garden. The point is to prevent weeds, to regulate the humidity in the soil and to achieve continuous fertilization. More on this following later.
It is not unusual to see gardens in which just a few crumbs of mulch were draped on the beds. Then the house owner certainly wonders why he has done that at all. It has no effect and looks pretty stupid. The layer of mulch has to have a thickness of about 5-7 centimeters, if not it can hardly develop its advantages. Is it less it has no effect, is it more the mulch starts to get moldy.
Only if the mulch is applied thick enough, it can prevent weeds, since the roots of flying seeds can not reach the underlying soil. The distance is too long, as that they could grow so deep in time to obtain the necessary nutrients. Some weeds do it anyway, but these have then so little hold in the loose mulch, that they can easily pulled out, together with its roots. So weeding is furtheron an easy job.
Moreover, a homogeneous surface of mulch is a symbol of a well-cared garden - but the mulch can do even more. Because it now forms the surface, it protects the underlying soil from drying out. That means that you have to water less and extreme drought or wet phases are balanced in a natural way. Also the mulch protects the soil from erosion, as sudden heavy rains fall on the absorbent material, instead of turning the ground into mud holes.
Another advantage is that the mulch decomposes continuously and thereby composts itself. The organic material is thus transformed into a natural fertilizer. About once a year you should replace this transformed volume. It must be noted that mulch binds nitrogen at the first application.. So you should deploy some nitrogen fertilizer to avoid deficiencies in the plants .
There are different mulch qualities: medium and fine, as well as reddish decoration mulch. In order to achieve the greatest possible effect the middle quality is to recommend. Because the fine mulch flies away at the first gust of wind, while the coarse mulch has usually too large cavities to hold the moisture.
You may mulch at any time. But the most advantageous is to do it when all the plants are cut back. Then you have enough space to work and do not have to meander through the branches. The mulch in the photos is wet, by the way. It usually has a lighter color, when dry.
Garden trick :
If you already have many smaller plants in your flower beds, you can cover it when mulching with upturned flower pots or buckets. So the plants are not damaged, will not be buried and you can throw the mulch without hesitation into the flower beds. Then, to obtain a uniformly smooth surface, not the rake is best, but a broom is !