Mulch can be divided into two major categories: organic and inorganic. Organic mulch is, as the name suggests, composed of plant matter, paper, manure, and other plant and animal products. Organic mulch decomposes over time, breaking down into the soil. Inorganic mulch, such as rock or rubber, does not break down. Let’s look at the types of organic and inorganic mulches commonly available to gardeners:
By far the most popular type of mulch, wood mulch in the form of wood chips, shredded wood, or tree bark are available at most garden and hardware stores, and may even be available through local municipalities or parks. Cedar and eucalyptus mulches are particularly well-suited for water retention and for keeping pests away from your perennials.
We recommend aged hardwood mulch, applied in a light layer, around your flower beds. Well-aged wood mulch is an ideal choice for flower beds, as it adds nutrients to the soil as it decomposes. Softwood mulch, usually made from pine, can add a bit too much acidity, and doesn’t decompose quickly. Using freshly ground, “green” mulch from a municipality or your own wood-chipping endeavors may release too much nitrogen into your soil, so don’t place fresh mulch directly near flowers. Commercially-available wood mulch has been aged and dried, and may even be colored for aesthetic appeal!
Bark mulch is made from tree bark, usually from waste materials in manufacturing. Bark mulch can be applied just like any other wood mulch, but it tends to last longer. It’s perfect for soils that dry out too quickly, and you won’t need to replace it as frequently.
Grass Clippings for Flower Beds
Your mower likely has a “mulch” setting, but is it smart to use grass clippings as mulch for flower beds? Using grass clippings as mulch provides your garden with water conservation protection from heat. Plus, the decomposing grass will release nitrogen into your flower beds. Never use grass that has been treated with herbicides, and avoid using grass if your grass clippings contain weeds. Grass as mulch also requires some amending. To complement the nitrogen of cut grass, try including some carbon-releasing material in your home-grown mulch, such as shredded leaves, hay, or newspaper. Create mulch using two parts of your carbon-releasing organic amendment for every one part of nitrogen. Then, apply in a thin layer.
Cocoa Chip Mulch
Cocoa bean hulls have picked up popularity in recent years for their pleasant, chocolatey scent and attractive color. This unique type of mulch is excellent for flower beds, as they provide nutrients, protection, and water retention. Cocoa hulls decompose very quickly, so don’t apply them thickly or water excessively to avoid mold.
Recycled Paper as Mulch
Need a heavy-duty weed combatant? Cardboard or shredded newspaper can be an effective weed suppressant, especially during the winter months. However, we don’t recommend using paper as your sole source of mulch: it may blow away! Instead, use it as a bottom layer, then apply a top dressing of organic mulch.
Straw as Mulch
Straw breaks down more slowly than grass clippings or leaves, and provides plenty of protection against heat and cold. It’s a favorite among vegetable gardeners and fruit growers, too, as straw keeps mud off of dangling produce. For flower beds, straw isn’t the prettiest choice, but it certainly works, and may be perfect for protecting tender bulbs over winter.
Recycled Rubber Mulch
Rubber mulch is usually made from shredded tires, and doesn’t decompose. While rubber mulch is a popular choice for walkways and playgrounds, but isn’t suitable for flower beds: chemicals and dyes from the rubber may leach into the soil.
Tips for Mulching Flower Beds
So, what is the best type of mulch for flower beds? And, how can you make the most of your annual mulching? Here are a few tips from our experts on mulching flower beds:
For springtime mulching, wait until the heaviest rainy season has come to a close. Remember, mulch prevents water loss, so mulch in the rainy season can keep your soil from drying out appropriately.
Measure your garden, and think through how much mulch you’ll need. Most commercially available mulch is labeled by cubic foot or yard. Weed before you start. While mulch can prevent weed seeds from taking root, it won’t smother existing weeds.
Use a rake or trowel to even out the surface of the flower bed before you start mulching. Remove old wood, leaves, and dead plants before mulching.
Choose an organic mulch for your flower beds, such as wood chips or bark. Wood mulches provide a slow release of nutrients as they break down, and you won’t need to pull the mulch later in the season.
Colored mulch can stain your walkways during overwatering, so spread mulch on a day when no rain is expected. After 24 hours, the mulch should be fully dried and the colors won’t bleed.
When using wood mulch, spread a layer two to three inches thick on your beds.
Get as close as possible to the base of perennials and shrubs, but don’t mulch up the sides of their stems or trunk. Mulch piles can create a breeding ground for pests.
Worst Types of Mulch for a Flower Garden
At the end of the day, the best kind of mulch for a flower garden is the one that works for your garden! We recommend an organic mulch that protects your plants and adds nutrients to the soil, and most gardeners prefer wood mulch or cocoa hulls for aesthetics and ease of application. However, straw, grass, hay or paper may work for thermal protection and certain types of gardens. Inorganic mulches, such as tarping or rocks, have their place in the landscape, too, but avoid rubber mulch or anything dyed with inorganic coloring.
How to Take Care of Your Flower Beds
Once you’ve finished mulching, your flower beds will be ready for another year of floral performance. Here are a few tips for maintaining your mulch, and for keeping your beds looking fresh:
If mulch develops mold, use a hand rake to turn the mulch, allowing the moldy parts to become exposed to airflow. Most molds that grow on mulches won’t injure your plants, but mitigating the mold is easy and quick.
If weeds sprout through the mulch, simply pluck and discard them. Some weeds are inevitable, but your new mulch will keep their numbers low!
Your wood mulch will likely fade over the spring and summer. For a fresh appearance, turn the mulch regularly.
When you re-mulch your bed in fall or the following spring, clean out some of the old mulch, and pull any large chips that aren’t decomposing quickly.
Once you begin mulching, stay on top of it. If using compostable mulch, you will likely need to apply mulch yearly. Going without could cause damage to your plants’ roots. While mulching isn’t the most entertaining garden chore, it goes a long way in protecting your plants and keeping your garden happy!