Perennial plants are the backbone of every permaculture garden, and the more established these perennial plants are the easier time they will have pushing through the mulch. Mulching has a lot of benefits, from protecting the soil to retaining water, but some perennials will have an extremely hard time growing through the mulch. Not all mulches are equal, some are so dense that they do not let light get to the soil, while others have such a large volume that pushing through them will be impossible.
Established perennials will grow through the mulch, but if the perennials are grown from seed then you have to remove the mulch and plant them directly into the soil. Plant bulbs will have no problem growing through the mulch even if the mulch is rather thick, they can do this because they have a lot of stored energy in the bulb. Perennial shrubs will also be able to grow through the mulch just make sure to cover their crown lightly.
If you tend to get a lot of leggy perennials then one of the reasons for this is that the plants have to use a lot of energy to grow through the mulch. The thicker the mulch is the slower they will be able to break the surface, and once they do they will focus most of their energy on growing tall. This tends to happen especially if you have a lot of different plants growing in a small area, some are growing way too fast which puts a lot of pressure on the perennials.
The more competition a plant has for sunlight the leggier it will become, so make sure to cover your perennial plants only with a thin layer of mulch. My personal recommendation is to use mulches that tend to break down relatively fast, like hay, grass, and straw. This way the mulch will not only protect the perennial plants but also feed them as they are decomposing. If you want more information about what kind of plants grow through the mulch then check out my recent article Will Plants Grow Through Mulch? ( Organic And Inorganic Mulches ).
Perennial Seedlings Growing Through Mulch
Perennial seedlings will not be able to grow through the mulch, mostly because mulches are excellent at suppressing weeds and their seeds from germinating. Mulches not only stop weed seeds from germinating but they will stop the germination of any kind of seeds. This is why it is so important to plant the perennial seeds into the soil directly, and most importantly do not cover these seeds up with any kind of mulch. In case you want to attract Monarch butterflies to your garden then check out my recent article Plants That Attract Monarch Butterflies ( Top 13 Plants ).
Established Perennial Plants Growing Through Mulch
If you have established perennials that are at least 2-3 years old then most of these will be able to grow through the mulch. Although some perennials will be able to grow through the mulch I still do not recommend you mulch the area for several reasons. A lot of perennials tend to grow relatively slowly, and pushing through the mulch will slow them down even more. What tends to happen is until the perennial plant pushes through the mulch the weeds have already taken over and will basically choke out the perennial plant.
Perennial Bulbs Growing Through Mulch
Perennial bulbs will grow through the mulch, provided that they will survive the winter. Bulbs tend to contain a lot of energy which they use to push through the soil and mulch. The bigger the bulb is the easier time it will have pushed through the mulch. Smaller bulbs on the other hand should be covered only by a thin layer of mulch, especially if you are using wood chips. Just keep in mind that a lot of bulbs will rot away if they do not have enough energy to push through the mulch, so mulch them thinly. If you want to know which mulch is the best for vegetable gardens then check out my recent article Best Mulch For Vegetable Garden ( Top 10 Mulches ).
Perennial Shrubs Growing Through Mulch
Perennial shrubs will have no problem growing through the mulch although some tend to be extremely sensitive to the type of mulch you are actually using. Established perennial shrubs that are at least 2-3 years old will push through even a thick layer of wood chips mulch. If you have shrubs that you cut back to the ground every year then make sure to cover their crown only with a thin layer of mulch, just enough to protect them through the winter.
In Conclusion
As you can see established perennials will have no problem growing through the mulch, although the thicker the mulch is the harder it will be for them to grow through it. If you are growing perennials from seeds then it is extremely important to remove the mulch and place the seeds into the ground, also do not cover them up with mulch.