This brochure is one of the educational resources provided by Mother Nature’s Backyard – see http://mother-natures-backyard.blogspot.com/

1. How to apply mulch: mulches need to be thick enough to
effectively prevent evaporation and weed growth. A good rule
of thumb is 2-4 inches deep for organic mulches and 1-2
inches deep for inorganic mulches. Be sure to leave a 6”
circle of bare ground around the trunk or stem of each plant
(to prevent fungal diseases). In most cases, mulches should
be applied in a flat layer (rake to smooth) and not mounded;
never mound up mulch around tree trunks. Mulches: Water-wise and Good Looking
When to apply mulch: organic mulches break down over
One key element of water-wise gardening is insuring
time, so you’ll need to re-apply fresh mulch. Inorganic
that water doesn’t evaporate away before your plants use it.
mulches may settle, so they also may need occasional
Two good ways to do this are: 1) to use water-efficient
renewal. A good time for mulching is in the fall, after you’ve
irrigation methods (see our brochures on Water-wise
completed your fall pruning and before the winter rains begin.
Irrigation) and 2) to use garden mulches.
How much will I need? Mulch is usually sold by the cubic
A mulch is simply a protective layer spread on the
yard. Here’s the easiest way to calculate your needs:
surface of the ground. Mulches serve many purposes, among
them preventing water loss from evaporation and runoff.
1. First, figure out the size of the area you want to cover in
square feet (multiply the length times the width).
Mulches also suppress weed growth and can be used to make
your soil warmer – or cooler. They provide access and give
2. Next, decide how deep you want your mulch to be, in your garden a tidy appearance. Some mulches are used
inches. simply because they are decorative. For example, you might
use an attractive pebble mulch around a fountain. Some
3. Now multiply the size of your garden in square feet (#1) common uses for mulches in the home garden are:
by the depth of your mulch in inches (#2).
 As path and walkway materials (permeable walkways)
4. Divide the number you get in #3 by 324. This is the
 Around trees and shrubs
number of cubic yards of mulch you will need.  In the vegetable garden and under fruit trees
 As a ground cover in unplanted areas
Learn more about water-wise gardening at: http://mother-natures- There are two main types of mulch: organic and
inorganic. Organic mulches are made from plant materials
backyard.blogspot.com/. You can e-mail your mulch questions to:
including wood, bark, leaves, etc. Inorganic mulches come
mothernaturesbackyard10@gmail.com from non-living sources.
When using mulches with California native (and other
water-wise) plants, it’s important to consider the type of
‘natural mulch’ that surrounds the plant in nature. Mother
Nature is the expert when it comes to mulches! You can’t go
wrong by imitating nature’s mulches in your own garden.

2. The basic types of mulches and their best uses in the garden are outlined below:
None No mulch/ bare ground Annual wildflowers; local native grasses; native Salvias, Penstemons & Buckwheats
Chipped bark Many native trees & shrubs; pine & fir trees; many other trees, shrubs
Shredded Bark (‘gorilla hair’
Many native and non-native trees & shrubs; best choice for slopes, hillsides
mulch)
Many native and water-wise plants; be sure to get fresh from a tree trimmer (free
Wood chips
mulch from city/park mulch piles may contain weed seeds)
Nut hulls ‘Woodland’ type plantings; around strawberries, fruit trees; as decorative mulch
Organic
Pine needles Under forest-type trees/plants (pines, etc); on slopes; around ‘acid loving’ plants
Straw/Grass clippings Vegetable garden; cheap, but may have weed seeds
Composted ‘green waste’ Vegetable garden & conventional (non-native) flower beds
Commercial ‘topper’ or ‘top
Conventional (non-native) flower beds; roses
dressing’ products
Gravel; fine-grade crushed
Annual wildflowers; bulbs; desert plants; native Salvias, Penstemons, Buckwheats;
rock (small size particles);
pots & planters; walkways & seating areas
decomposed granite
Crushed rock (larger size) Decorative uses; in rain gardens & infiltration swales; pots/planters; bulbs
Pebbles (rounded rocks) Decorative uses; around ponds; in rain gardens & infiltration swales; pots/planters
Inorganic
Shredded/Ground rubber Play areas; around fruit trees
Glass & other decorative Decorative uses; around ponds; in rain gardens & infiltration swales; pots/planters
Plastic sheeting/ weed-block Under pathways, seating areas; temporary mulch (when clearing weeds/grass)
Newspaper/cardboard As temporary mulch when clearing an area of weeds/grass or under pathways