Much Ado about Mulch

Mulch is a good gardening habit but not mandatory. But, ooh boy, do the benefits make it worth the effort! A really good job of mulching your garden usually

  • Inhibits weed germination and growth (and not only are weeds unsightly, but they also they steal resources from your plants!)
  • Holds in soil moisture, protecting your plants from drying out so fast
  • Moderates soil-temperature fluctuations (this benefit is especially valuable during that turbulent-weather period in spring when you don't want your plants to be stressed)
  • In cold-winter areas, protects plant roots from winter cold and helps prevent frost-heaving, in which plants are literally pushed out of the ground by the natural expansion and contraction of the soil as it cools off and heats up
  • In hot-summer areas, helps keep plant roots cooler
  • Depending on what you use, adds a bit of welcome nutrition to your garden as it breaks down

Sound like good enough reasons to use mulch? Yeah, I thought I'd convince you. Read on for the lowdown on mulches.

Knowing your mulches

First of all, I can't name any "right" or "best" mulch. Benefits vary in different climates and parts of the country. Some mulches are free, right in your own backyard; you can purchase others locally. Experiment to find out what you and your plants prefer.

Table 4-2 provides the basic information you need to know about some of the more popular options.

Table 4-2

Comparing Mulching Options

Type of Mulch



Grass clippings

Is cheap, readily available, and easy to apply

Decays quickly, so you have to replenish it often; if you use weed killers on your lawn or nitrogen-heavy fertilizer, it may adversely affect other parts of the garden; can turn slimy if you apply more than an inch or so at a time; if the grass went to seed before you cut it, the grass seeds can germinate in your garden beds (yikes!)

Wood or bark chips

Looks neat and attractive; stays where you put it; is slow to decay

Pine bark mulch is fairly acidic, which you may or may not want for your garden; if you apply too deeply (over 3") or apply a deep layer up against tree and shrub trunks, you may create a hiding spot for a bark-damaging rodent, especially during winter

Decaying leaves

Smothers weeds very well; helps hold in soil moisture

Is not especially attractive; if it contains seeds, they can germinate and become a weed problem; if the leaves are soft, like maple leaves, the mulch can mat; if it's acidic (oak especially), it can lower your garden soil's pH


Is free and plentiful if you have your own compost pile; adds nutrients to the soil as it breaks down

Makes a good place for weeds to take hold; fresh compost (especially if it contains manure or grass clippings) can burn plants

Peat moss

Looks neat and tidy; is versatile — also functions as a soil amendment

Can be expensive; if dry, will repel water; becomes crusty over time


Is cheap and easy to apply

Is so light it can blow or drift away; may harbor rodents, especially over the winter months; isn't very attractive for ornamental plantings


Is cheap and easy to apply

May harbor rodents, especially over the winter months; isn't very attractive for ornamental plantings; probably contains weed seeds!

Type of Mulch Advantages



Has a nice, neat look

Can allow weeds to sneak through;


(though not "natural");

provides no benefits to the soil

or stone

is easy to apply; won't

wash away easily and

will last a long time;

doesn't need to be

replenished over the

course of a season

in colder climates

Keeps weeds at bay; Watering and feeding is hard (you holds soil moisture and need to cut openings for plants); can warmth in be difficult to apply unless you're doing an entire area at one time; isn't very attractive

Plastic (garden plastic, black plastic)

How to apply mulch — and how much

If you're ready to start applying mulch to your garden, here's what you need to know to ensure you get the best possible use of your mulch:

^ When you plant: Applying mulch right after planting something is easy. Use a shovel or scoop with a trowel. Spread the mulch over the root-zone area but not flush up against a plant's base or main stem (which can smother it or invite pests or disease).

Depth depends on the sort of plant. Annuals and perennials are fine with an inch or so of mulch; shrubs, roses, and trees need 3 or 4 inches or more.

  • During the growing season: Add more mulch midway through the growing season or whenever you notice it's depleted. You may have to get down on your knees or wriggle around a bit as you try to deliver it where it's needed without harming the plant or its neighbors. Again, use less for smaller plants, more for bigger ones.
  • In the fall or for winter protection: Depending on the severity of your winters and the amount of snow cover you expect (a blanket of snow can act as a protective mulch, actually), you want to cover an overwintering plant well. You can cut down perennials first and then practically bury them under several inches of mulch. You shouldn't trim back shrubs and rosebushes at this time, but you don't have to be as careful as you were with midsummer mulching because the plant is no longer growing actively. For freezing winters, 6 or more inches around the base of these is good.

These amounts are guidelines only. You have to tailor them to your climate, growing season, and specific plants.

To limit erosion, don't excavate large areas that are on a slope without planting or at least mulching soon, especially during the spring, when rainy weather can cause washouts.

Water, Water Everywhere: Tackling Watering Issues

Sure, without moisture, plants die. Everyone knows that. But you may not know why water is so incredibly vital. The answer is threefold, actually:

1 Sufficient water pressure within plant tissues creates turgor, or rigidity, so the plant can stand up. A plant without turgor pressure collapses.

i Water keeps nutrients flowing through the soil, the roots, and the plant parts as they should; it keeps the show going.

1 The show is the chemical process of photosynthesis, which you no doubt remember from biology class in school. The plant uses light, carbon dioxide, and water to make sugar (a pretty impressive trick). Without photosynthesis, plants can't grow or develop flowers or fruit.

Keeping a close eye on your plants is easier said than done, of course, but the following sections tell you what you need to know, to keep in mind, and to watch out for when evaluating just how much moisture your garden needs.

Providing plants with the right amount of moisture

How do you make sure your garden has the right amount of moisture? Relying on natural rainfall would be nice, but natural rainfall is hard to count on (though it does kindly water your garden for you from time to time). Gardeners always seem to have to supplement the moisture, a little or a lot. You just need to keep an eye on things and pay attention to your plants. Read on for the warning signs of too much or too little water.

On the dry side

If you know what to look for, you can figure out your plants' watering needs. Plants actually prioritize when water-stressed, so look for the early warning signs:

  1. If a plant isn't getting enough water, flower petals and buds are the first things to be jettisoned (or fruit if it has developed), because making and maintaining them takes so much energy and water.
  2. Next to go are the leaves, which shrivel.
  3. Then the stems flop.
  4. Underground, the roots go limp.

Obviously, if your garden is in this condition, it needs more water.

Bogged down

Telling when a plant doesn't have enough water may seem to be a snap, but keep in mind that there's definitely such a thing as too much water. If puddles form in your garden or an area of it's quite soggy, all the pores in the soil fill. When this happens, no free oxygen, which needs to get to the roots, is in the soil (See "Air! Air! Plants Need Air!" later in this chapter).

Meanwhile, some plant diseases (like mildew and blight) travel via water and can easily develop and spread in soaked conditions. Sodden roots blacken and rot, and all the aboveground growth subsequently dies. Garden plants in these circumstances, of course, need less water. See "Dealing with drainage problems" later in the chapter to find out what to do.

Unfortunately, an overwatered plant looks the same as one that's underwa-tered! The reason is that an overwatered plant is actually suffering from dehydration because the roots have been damaged by too much water (actually, too little oxygen, because the water has displaced the oxygen); the roots can't absorb water, so the plant wilts. One difference is that overwatered plants don't recover from wilt when you apply additional water, but underwa-tered ones generally do.

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