5 Tips for Landscaping with Mulch

red mulch with a watering can, trowel, plants and containers

You may be asking what’s the big deal about mulch? What good does it do? How is it best used in my landscaping? Your options for mulch are varied, from organics like peat moss and lawn clippings to synthetic and inorganic options like black plastic and stone or gravel. But, what’s best to use where? Here are five tips we think will help in the selection and use of mulch in Oklahoma landscapes.

How much mulch?

Mulch refers to any material that is spread or laid over the surface of the soil as a covering.  It’s used to help retain soil moisture, prevent erosion, keep the soil cool, control weed growth, and generally make the yard look better.

While you may think mulch around plants and trees is primarily for looks, it has a much more important role in keeping plants healthy and thriving. It’s particularly beneficial to use with plants that need more moisture as the days get hotter and rain less frequent. But, even plants that are considered drought resistant may benefit from proper mulching.

If a little mulch is good, is more better? Not always. The secret to a healthy landscape is to know when enough is enough. Too much can kill your plants. If mulch builds up over four inches, it may actually become water repellent.

Now, the very thing that should help retain moisture will prevent moisture from reaching plant roots. It may also prevent essential air from reaching the roots. Especially harmful is “volcano mulching,” where deep layers of mulch are piled up against the trunks of trees.

You shouldn’t have to mulch every year. Replace mulch every few years, but you need to turn organic mulch about twice a year.

Organic Mulch

wood chips

Organic mulch not only provides the benefits described above, but it will also improve your soil’s fertility and its organic content as it decomposes. The dryer and woodier the mulch, the slower it will decompose and the fewer nutrients it will give to the soil.

Each type of organic mulch has its own use. Our guide describes some of the organic mulch types available and the plants they work best with in Oklahoma. These options include peat moss, sawdust, cotton burrs, lawn clippings, wood chips, and shredded newspaper.

Compost is another organic mulch option. While some people use the words mulch and compost synonymously, they are not the same thing.  Compost is decomposed organic matter such as garden waste, kitchen scraps, leaves, grass clippings, straw, and even manure.

While compost is not particularly high in essential nutrients, it does provide carbon and nitrogen, which improve the soil for plant growth. You’ll need to put a thicker layer of compost around plants for the full effect. Two to four inches is ideal, especially for perennials. Also, be careful that your compost doesn’t have viable weed seeds. You don’t want to spread a mulch that is going to make more work for you.

Synthetic Mulch

Some examples of synthetic and inorganic mulches are black plastic, landscape fabric, stone, and gravel. These mulches do a good job of holding moisture and blocking weeds. While they don’t add any benefit to the soil, they don’t decompose and don’t have to be replaced as often as organic mulches.

Plastic and landscape fabric are good choices for around foundation plantings and other shrubs and trees. Since these plants don’t need frequent fertilizing, you won’t be working in these beds often and don’t have to worry about weeding them during the summer.

Because plastic gets very hot in the summer, along with smothering weed seeds, it can also kill plant roots, unless there is sufficient moisture. Be sure to cut holes in the fabric to allow sufficient water to pass through.

If you like the functionality of plastic or landscape fabric but not the look, you can always add a thin layer of bark mulch on top of the plastic or fabric for camouflage.

Gravel and stone work well as mulches in areas that require good drainage or beds with plants that like a little additional heat, like Mediterranean herb gardens and rain gardens. Stone is hard to remove, so give it a lot of thought before using stone or gravel as a mulch.

Fertilizing and Mulch

Since mulch alone, even composted, does not provide needed nutrients, fertilizing along with mulching is essential for healthy plants in moist and cool soil. The key is to use the right kind of fertilizer and to apply it in moderation.

The most common fertilizers are made from salts of nitrogen, phosphorus, and potassium. These are nutrients used by plants in the largest quantity. They will be labeled as N-P-K: 5-10-10, 20-20-20, or similar numbers. The three numbers are the percentages of those three nutrients in the product.

Remember, because they are salts, too much can kill your plants. Use the product in the amount recommended on the label to help your plants flourish. Over-fertilizing can also delay blooming in some plants. If they get too much nitrogen, they’ll grow a lot of foliage and flowering will be delayed.

Composted manure may also be used to fertilize plants. Adding manure to your compost pile will provide the extra nitrogen many plants need. Poultry manure has the highest nitrogen content of all livestock.

Pet Safety Concerns

black dog surrounded by bags of mulch

What about mulch and your pets? Generally, mulch poses little threat to cats, though it can double as an outdoor litter box. On the other hand, some organic mulch types can be dangerous for dogs, who often chew on it. So, if you have a dog that spends much of its time outdoors, pick your mulch with care. Read the labels and select products that are labeled as pet safe.

Mulch made from cocoa shells, also known as cocoa bean mulch, is especially toxic to dogs. While others types of mulch may not be toxic, they can be harmful, especially if dogs chew on it. Some pets may show signs of allergic reaction to certain types of mulch.

Is dyed mulch more harmful? Not usually. Mulch color is made using either iron oxide (for red) or carbon black (for black), both considered safe for use around pets and humans.

If you have pets and are considering using mulch in your yard, talk to a veterinarian about any risks.

Now that you know more about mulch options for your Oklahoma landscaping, it’s important to select the type that works best for you and your plants. For help with garden design and landscaping, contact us today. Call 405-418-4880 for a quote.