Beneficial Mulching, and Types of Mulch You Should Never Use

I am already dreaming of fall. Fall is a good time to add a fresh layer of mulch to the garden.This view of the front garden shows wood chip paths and pine straw used as mulch. Good organic mulch has many uses and benefits:

*Mulch is often beautiful and gives the garden a fresh and neat appearance.

*Mulch retains moisture around plants without making the soil soggy.

*Mulch helps to suppress weed growth.

*Mulch protects plant roots from temperature extremes in both summer and winter. 

*As it breaks down, a good organic mulch will feed worms, beneficial fungi and micro-organisms in the soil.

*The worms and other earth dwellers will pull aging mulch into the soil, improving soil texture far better than any tiller and increasing soil nutrients available for plants.

*Mulch can prevent soil erosion.

*A layer of mulch around a plant will protect trunks from mowers and weed trimmers.

*Mulch helps to prevent soil compaction from foot traffic.

*Mulch can be used to create inexpensive but lovely paths.

There are some important things to know before applying mulch.

When applying mulch around a plant, be sure to leave a "doughnut hole" around the plant's trunk. Never pile mulch in a volcano next to the trunk. Also, do not apply more than a 2-3 inch deep layer of mulch around a plant. Wider is better than thicker. Too much mulch can make water difficult to penetrate through to the soil and over time can even suffocate plant roots.

Also, never apply mulch so that it touches your house. Termites will use the mulch as a pathway to your siding.

Here are some common mulches and how to use them:

Compost:Composted organic matter provides nutrients to both plants and soil organisms. It can be incorporated into the planting hole at planting time, as well as be used as a mulch on top of the ground. Because of its fine texture, compost is not as effective at preventing weeds as some other mulches.

Wood chips and shredded bark:These are beautiful mulches. Wood chips and shredded bark make great garden paths, but fresh wood chips and bark will pull nitrogen out of the soil as it ages, possibly decreasing available nitrogen for nearby plants. Therefore, use aged bark or chips around plants, rather than fresh. For the same reason, fresh mulch should not be incorporated into planting holes.

Pine straw:This is an economical, attractive mulch. It contains compounds that inhibit seed germination, so it is great for suppressing weeds. It is acidic, so is beneficial for alkaline soil or for use around plants that like acid soil.

Newspaper and cardboard:Newspaper or cardboard will block light and suppress weeds. Cover with another type of mulch for appearance. Newspaper and cardboard is very useful when establishing a new garden. There is no need to till or tediously pull or spray old vegetation. Simply cover the area with a layer of newspaper or cardboard, wet thoroughly, then top with several inches of good garden soil and plant. Avoid newsprint with colored dyes.

Straw:Straw or hay is often used in vegetable gardens. Unfortunately, it  frequently contains weed seeds, and it provides the perfect environment for mice and voles. Its light color may not appeal to some gardeners.

Pebbles and rocks:These look most at home in a rock garden (of course!) or a desert application. Pebbles and rocks absorb heat from the sunlight during the day, then release the heat at night, so they can help protect plants during chilly nights. Water drains through easily. An edging is needed to prevent the pebbles from washing away, and weeding can be a nightmare. A layer of landscape fabric beneath the rocks will postpone the weed problem but will not prevent it. In fact, it can make the problem worse. Landscape fabric deteriorates over time and will allow weeds to take hold. Believe me, pulling weeds through the rocks and landscape fabric can make the saintliest gardener cuss, and removing old landscape fabric is not fun, either. Pebbles and rocks are probably best used in applications where the gardener can spray weeds without worrying about harming plants, such as  paths and parking areas. Forget the landscape fabric.

Dyed wood mulch:Wooden pallets and various types of wood trash are chopped up and dyed. This mulch may contain harmful chemicals, including creosote and arsenic. Rain will wash the color out of the wood, and you may see it running onto your patio or drive. Some people like the colors, but I would never use it.

Dyed rubber mulch: This stuff is made from old rubber tires. Instead of being disposed of in a toxic waste dump, the tires are shredded and dyed in an assortment of colors, packaged nicely and then sold as mulch. It stinks like petroleum in the summer and leaches pollutants into the environment. To my horror, rubber mulch is often used on playgrounds. Never put this material in your garden.

Here is another view of mulch used in my garden. It has been raining, so everything looks fresh.

Imagine what my garden would look like if all the mulched areas were bare dirt and weeds! 

Strategies for Dry Shade Gardening

Outside, nestled in the shade of a large Japanese maple in front of the house, are a variety of plastic pots containing ferns, hydrangeas, and native azaleas that are destined for the woodland garden. These were recent purchases at a local 50% off sale.A few of my new plants, awaiting their permanent homesIt looks like a mini-nursery, and I am waiting in anticipation of cooler weather. Lou, who has to dig the holes for me, is maybe not so eager.

Autumn will soon be here, and in the southeastern US, this is the best time for planting and transplanting perennials, shrubs and trees. Since our ground does not freeze in the winter, plants will have months to establish themselves before next year's summer stress. Unfortunately, planting in the woodland area is not a matter of just digging holes. Shade is priceless in my part of the world, but the downside of all those trees is that their roots extend throughout the garden, sucking up available moisture. I have often put my shovel into the ground, only to find dry earth and lots of roots. This condition is called "dry shade", and it is one of the greatest challenges in creating a woodland garden. New plantings must compete with preexisting trees, as well as shrubs and other plants, for available water and nutrients. 

When planting in dry shade, there are a number of strategies to give ornamental plants a good start:

1. I get rid of all weeds in the surrounding area before planting. These weeds will compete with newly planted ornamentals and if given the chance will smother them.

2. It is ok to cut through small tree roots, but never disturb major roots. If there are a lot of roots, I usually try to find another spot. Those roots will grow back quickly, and my little plant may not have a chance in the root competition game. If I must plant in that spot, sometimes I will line the hole with newspaper, forming a biodegradable barrier that will hold out competing roots until my plant's roots have had a chance to grow. Another thing I have done for perennials, if their root systems won't spread too far, is to plant inside of a large plastic pot buried in the ground. This will keep competing roots out. This also gives protection against root-eating critters such as voles. 

3. Add mulch and soil conditioners to the soil at the time of planting. I do this 100 percent of the time. I usually make about a 50/50 mix of soil conditioners and native soil. I use home-made compost as well as soil conditioners I have purchased. These amendments improve the soil structure so that it will hold moisture longer. Sometimes I also pile wet, rotting leaves and other debris from the forest floor in the bottom of my planting hole.

4. Water the hole before planting. Of course, I also water the plant well after planting. It is very important to water new plants regularly for at least three to six months after planting. Remember that plants need to be watered deeply, not just sprinkled enough to wet the top layer of soil. Sometimes I have checked after I thought I had watered well, only to discover that the soil was bone dry less than an inch from the surface! The moisture needs to extend down far enough to reach below the plant. This is another reason I like to plant in the fall, as we tend to have wet winters that will promote good root growth.

5. After planting, I put a 2 to 3 inch layer of mulch around the plant. The mulch can be shredded leaves, pine straw, wood chips or any good organic mulch. The mulch should not actually touch the plant. The mulch itself holds moisture that will be available for the plant, and it also creates a small well around the plant that allows water to reach the plant's roots, rather than running off. 

Mulch will break down, improving the soil. This also means the mulch will need to be replenished. In our climate mulch breaks down rapidly, and we replenish it once or twice a year around most of our plants. 

6. Sometimes I create elevated mounds of improved soil in which to plant. This works well for plants that should be planted high because of their need for excellent drainage, such as azaleas and hydrangeas. Sometimes I find hollow spaces between large tree roots and fill them with good soil. I like to do this for ferns, hostas and other perennials that look good at the bases of trees. However, do not mound large amounts of soil directly over tree roots, and never pile soil against tree trunks. Elevated planting beds and pots beside the woodland steps allow me to have plantings where thick magnolia tree roots would otherwise make that impossible.

7. I like to plant shade-tolerant, drought-resistant plants. Natives will often do better than exotics. Remember that even these types of plants will need plenty of water when they are newly planted. They will not become drought-tolerant until their root systems are well established.  

If you have a wooded area filled with dry earth and roots, don't despair of planting. But here is a secret: You don't always have to add new plants for a natural area to look beautiful. You can just clean the space of weeds, maybe cut some lower branches from trees to allow room to walk, add a nice layer of mulch, place a comfortable bench or swing, and hang a bird house and some wind-chimes. Voila! Instant (or almost instant) woodland garden!There is always lots to see in a woodland garden!