There are neat mulches and there are messy mulches. Today neatness is in style which unfortunately is a little more work but the choices are many.
Mulches are usually 2 to 3 inches deep, but shouldn’t smother the plants and shouldn’t touch trees trunks. (And no treetrunk-mulch-volcanoes, please.)
The Neat Mulches:
Bark mulch is most common and most useful. It looks neat for about a season, then turns gray. Nuggets last about 2 years. There are special paints to spray on tired looking mulch that make it look neat and new. With it you can keep up with the Jones’ expensive landscape service look.
Wood chips (which is basically just chipped and shredded wood) looks pretty neat, but not as good as bark mulch. Both of these use up nitrogen as they decompose, so plants may need fertilizer under the mulch.
Buckwheat hulls are expensive but elegantly subtle and are the favorites of competitive perennial gardeners. Sometimes they blow off in the wind.
Cocoa Hulls are similar to buckwheat and smell like chocolate. Marvelous for chocoholics, but they contain a natural chemical that disrupts the growth of a few plants.
Good compost makes an excellent mulch and enriches the soil as well.
Peat moss looks good but dries out and when it does, water won’t go through it at all. Being acid, sometimes it requires extra lime to keep the soil at an optimum pH of about 6.5.
Crushed stone is very neat… at first… but the devil to deal with ever after because of weeds and decaying leaves. (You can use a blower if there are no delicate plants.) To prevent weeds rooting into the soil below, stone should always be laid on top of a good weed retardant fabric.
The Plastic Mulches:
Weed retardant fabric mulches have minute holes that allow both air and water through and are excellent. They are not cheap but they really save work, keep weeds down and keep the soil healthy. They can be hidden under neat bark mulch.
Ordinary black plastic is often used, especially on vegetables, but holes should be punched for water to run through. Tomatoes like the warm soil it produces, but are even more productive under red mulch.
Clear plastic is not good because it gets hot underneath in sunlight and cooks plant roots. However, it may be used to warm up cold soil in a seedbed in early spring, then removed when the plants grow.
The Messy Mulches:
Newspaper when thick and wet, smothers even the most vigorous of weeds. Eventually it decays and can be dug under, however there is a concern that the dyes contain heavy metals, so current recommendations are that it not be used for vegetables. For a neat look, the paper may be covered with a thin layer of expensive bark mulch, chocolate or buckwheat hulls. It’s an inexpensive way to make paths.
Grass clippings are useful and adds to soil health. But usually no more than one inch at a time, so each layer can dry out. Extra nitrogen is required as green grass decays, and when too deep, it gets slimy.
If used for vegetables, then only fertilizer and lime should be put on the lawn it comes from. No herbicides, no fungicides or insecticides.
Hay may sound good, but make sure its seed free or you’ll be weeding out tough pasture grass forever.
Seaweed is the king of mulches. It smells nostalgically like the sea, and since is has the best nutrients and growth hormones, your garden will really thrive but don’t overdo it. It has to be well washed first to get out all the salt.
Composted manure is sometimes used as a top dressing, but carefully follow the quantity directions on the bag. A little is a good thing but too much can be a disaster.
Leaves are useful, but no more than an inch or so for they tend to mat and some get slimy. However, if the leaves are chopped up first, with the lawnmower, before raking, then they don’t mat as much. Oak leaves, which are more acid, stay dry and crisp all winter. Pine needles also are acid. Any combination of all of the above is fine, depending on what’s handy.