A Gardeners Forum Forums General Discussion Plant pests and problems When & When not to Mulch

Can anyone help me with information on what shrubs and perennials can take mulch and which ones do not like mulch? I have been looking after the gardens in a nine year old golf course and there is a tendency to mulch everything. This may or may not be causing stress on some of our schrubs that are slowly producing smaller and fewer leaves. This is especially true with our larger Euonymus (Burning Bushes)that were doing well for six or seven years. We have about five to seven inches of mulch on our tree islands and even though the burning bushes are top dressed with heavily composted soil and fertilized with slow release 24/6/14 they have been losing ground for the last 3 or 4 years. They are planted in part shade beneath large Hemlocks with no low branches.

Any help on when not to mulch would be appreciated.

Regards
Jim

I've read that mulching should be 2- 3.5 inches, that when it gets deeper than that it can cause water logged soil more so in clay soil. Extended periods of wet soils in spring are most damaging to a number of perennials, azalea, rhododendron, conifers in general, and taxus or yew in particular.

Excess mulch, particularly if applied right against the stem or trunk of landscape plants, also leads to constantly wet bark and conditions favorable for disease development.

I found this online: Extra heavy mulch layers in autumn are often a haven for rodents to nest, which may lead to girdling (destruction of the food conducting vessel in the stem) of selected plants when wildlife food sources are covered with snow. In autumn, pull the mulch back approximately six inches or more from the stem or trunk of all woody plants to avoid rodent feeding.

I mulch everything though but not that thick.

There are a lot of expert gardeners here that will be able to give you the exact answer you need.

Glad you posted.

Definitely don't mulch up to the trunk. Leave a dip right around the trunk.

The only plant that I've heard doesn't care for mulch at all are carnations and that's just because they are self-seeding and mulch can make that difficult for them.

Are you using a shredded bark, large pieces of bark, or a rock type of mulch or some else entirely?

This sounds excessive to me, too. On a golf course, I imagine the mulch is being added for aesthetic reasons-- to dress things up-- and not because of the other benefits of mulch. So what you wind up with is too much of a good thing (which is bad). In addition to the above, I'd guess also that mulch this deep is hindering the soil's warming up in the spring.

I'd recommend starting over, that is, removing as much of the mulch as you can, then replacing that with only enough to pretty things up a bit. But this strategy might be dependent on what the mulch is, as TK asked.

We use the commercial mulch which is ground up bark and everything else made of wood that hasn't been treated. This includes old pallets, fences etc. I have read that the burning bush likes to keep its feet cool (Under Mulch). I never let the mulch contact the trunks or stems of any plant material.

I have lifted a few of the half dead shrubs and moved them to our nursery garden in good soil, in full sun with a light mulch covering. By the end of our summer we should be able to see if they pick up at all. My book on shrubs indicates a short to medium life span for this Euonymus but there is no reference to how many years are considered short or medium.??

Thanks for your help,
Jim