Mulch is beautiful, and it's a healthy contribution to the garden too. Mulch protects soil from losing moisture, from wild temperature swings, and it can keep some weeds from sprouting. But this garden dressing does have downsides. It can even be dangerous if you don't keep these tips in mind. 

Mulch is filled with decomposing materials. This process brings nutrients into the soil below, but it also produces heat. In very rare instances, it's enough heat to start a fire. To avoid this, keep your mulch cover no more than 2 inches high, especially in sunny spots that dry out quickly. 

Mulch beds should be well-watered to reduce the risk of overheating. Wet mulch and mulch blends that have large pieces (like wood chips) get less hot than mulch with small pieces. Decorative garden mirrors should never be placed in sunlight. Mirrors can focus the sun's rays on items around the yard and start a fire - whether it be mulch, shrubs, or other structures. 

Mulch is great for plants, as long as it is positioned properly. A "mulch mountain" under trees can weaken and even kill trees overtime. Apply mulch around tree roots but pile the mulch away from trunks. Mulch shouldn't touch the tree trunk because the excess moisture can create rot around the bark and open the tree to pests and disease.

Rubber mulch lasts a long time but is a bad choice for gardens. Rubber mulch can leach chemicals into soil, plants, and waterways. Rubber mulch isn't a good choice for pathways either because it gets very hot. 

Leaves and ground up twigs make great mulch. Many municipalities grind up tree branches and leaves after tree trimming projects and offer this mulch to residents for free. There are also apps for Apple and Android phones that match gardeners with mulch from local projects free of charge. 

Nature makes mulch every autumn, when the trees drop their leaves. Last year's leaf litter is a healthy addition to native and natural-looking garden beds. Not only is this mulch free of charge, but it's a lot less work than bagging the leaves up each season.