Questions re mulching

Asked July 9, 2018, 2:26 AM EDT

Hi, I have the following questions - I know mulch should not touch tree trunks - is this true for other plantings such as plants and shrubs? Is it OK to apply mulch over top of fallen magnolia leaves? There were many dried leaves under the magnolias. My garden helper just did this - if it's not ok, should we undo it? I saved & shredded fall leaves (not magnolia leaves) and applied the well-shredded leaves below mulch. Does this benefit the plants/soil?

District of Columbia County District of Columbia

3 Responses

Any organic (plant) material that you can spread thickly and prevent weed germination can be considered a mulch. Many people use shredded leaves as a mulch. All these organic mulch decompose and the results are like fertilizer, feeding plants. So, yes, mulch can be highly beneficial.

Yes, mulch should not be piled on any plant stems or trunks. That includes shrubs or flowers. Here is all kinds of mulch information:

Having mulch over your magnolia leaves will not hurt anything. Magnolia leaves take a long time to decompose and can serve as mulch under the magnolia, so they don't really even need to be mulched. There is a question about magnolia leaves on this page:


Thank you so much for this information, it is very helpful and I have read many of the resources you provided. I do have a few follow-up questions, first would you say it is OK to mulch directly over fallen bamboo leaves? I would guess they are 1” or less thick, and based on what I have read it seems OK?

In summer, What do you recommend mulching beds and around trees at 1 to 2 inches, or more? I do not like to remove mulch so I pile new on top of old, but so far issues with it being too thick.

I understand that mulch is not supposed to touch any plants. How do you recommend mulching a bed of daylilies, liriope or black eyed Susan’s for example? Is it better not to mulch plantings which are fairly thick? I have about a yard of empty space behind my plantings and the fence, does that area also need to be mulched or can I leave it bare?

The other question is how problematic is it if the area underneath the mulch is not perfectly weeded?

I blame typos etc on my smart phone

Of course, you can mulch over leaves if you want to.

We recommend mulch be 2-3" deep--all together. NOT that much added each year.

If plants are thick, they usually don't require mulch because they shade the soil and outcompete most weeds.

Any bare soil will not remain bare. Weed seeds will sprout.

Any vigorous weeds that have mulch put on them will simply grow up through the mulch. Tiny weeds are usually smothered. If you are trying to mulch over a patch of established weeds, cut down the weeds first if possible. Flatten the weeds. Lay 3-5 layers of newspapers, overlapping, over the weeds and then mulch.