Need Answers to your Questions on Garden Mulch? Let’s take a quick course: Garden Mulch 101.


Old Man Winter can be brutal on plants, trees, and shrubs. Taking time to prepare for a cold-spell is a no-brainer and your landscape will thank you for it. Choosing the right security blanket is as important as putting your plants to bed for a dormant winter’s sleep.

Portlanders live in a growing zone with very little snow, so we can take a more relaxed approach. In our area, it’s more about cold weather protection to prevent frost from settling on our foliage.


Mulch is a garden beds best friend during cold months. In Fall, add mulch 4 to 6 inches around the base of your plants. If spring arrives hot and early, rake back mulch from the plants a bit. If not, don’t remove it until the last frost date has passed.

In Spring, the ground warms more slowly. This is good because perennials aren’t fooled into breaking dormancy too early. You want the ground to stay cold until it really is spring. The drawback is that perennials may bloom late or soil may not be ready for spring planting.
Water evaporates more slowly from cool soil protected from the wind. If you mulch, you don’t have to water as much, saving time, money, and a precious resource. However, heavy rains can make the ground soggy and puddly for days. If beds become bogs, rake off mulch and let soil dry.
Without sunlight, some seeds don’t germinate, and sprouts may not have the oomph to push through the mulch. This prevents weeds, but it thwarts some good seeds, too. So, in spring, mulch after seedlings are up and at it.
Raindrops don’t hit the soil surface, so soil is less likely to wash away or splash onto plants. This keeps plants cleaner and free of some soil-dwelling diseases.


Everyone asks how much mulch to apply and when to apply it. There are no right answers. It depends on several factors, including your soil, rainfall, the type of mulch, and how weedy the ground is.
  • In most beds, mulches and soils, start with a layer 2 to 3 inches deep in spring. If it’s quick-drying sandy soil, go for the higher end of the range. For clay that drains poorly, go with the shallower depth. For a dense mulch like newspaper, use a much thinner layer.
  • If the soil is dry, water it before applying mulch. Pull any weeds.
  • Apply mulch just about anytime, remembering that if you mulch early in the spring, the ground may be slow to warm. If you mulch only in the winter, wait until the ground freezes. Mulch could delay freezing of the ground, causing roots to go dormant later than normal and possibly damaging them.

Mulches Are Not one-size-fits-all

Appearance. In a showy flower garden, you want a mulch that looks good without stealing the limelight: Try bark chips or shredded bark. For a woodland garden, leaves or pine needles are best. For a large, no-frills garden, grass clippings or newspaper are budget-smart.

Longevity. How long do you want the mulch to last? You may want to dig up a bed at the end of the season, in which case compost or another quick decomposer is a smart choice. Around permanent plantings, such as roses or flowering shrubs, a sheet of landscape fabric covered with bark nuggets or river stones will last for years.

For perennial beds, consider shredded bark, which lasts a long time. The bigger the mulch chunks, the longer they last. Leaves or grass clippings, break down faster than dry woody elements, such as straw, pine needles, or bark. Stone or gravel last an eternity.

Dark-color mulches will absorb and retain more heat from the sun than lighter ones. That’s an advantage in cooler regions but a disadvantage in hotter climates.
Some mulches won’t stay put. Small bark chips can wash down stream in a heavy rain. Mulches with heavy or large pieces are more likely to stay put. Those that form a mat, such as leaves and pine needles, are usually stable, too.
Organic mulches — grass clippings, leaves, manure, and compost — improve the soil. Stones and plastic don’t. Black plastic, unless it’s porous or perforated, grows a smelly, slimy coating. It also turns brittle and breaks into little pieces that escape the garden. Cheap landscape fabric is not worth it — weeds and roots will tangle in it.

Eenie Meenie Miney Moe:

Shredded, chipped, chunks, or nuggets. Usually pine, cypress, or hardwood. Attractive. Long-lasting, especially the large nuggets, but may look too chunky around dainty flowers.
Turn under at end of season to improve soil. Texture is too fine to suppress aggressive weeds.
Grass Clippings
Turn under at end of season. Can heat up or mold if too thick. Use 1-2 inches if fresh, 2-4 inches if dry.
Loose layer can be about 6 inches deep, will settle down. May contain weed seed.
Landscape Fabric
Use at base of flowering shrubs. Cover with thin layer of attractive mulch. Get good-quality fabric, or weeds and roots will tangle in it. Best type is bonded, nonwoven. (some of our homeowners do n0t see the benefit of surrounding shrubs with a barrier that inhibits rainwater, earthworm activity, breakdown of organic matter etc) Makes sense to me. Perhaps Mulch itself is best option.
Leaf Mold
Leaves composted two to three years. Turn under at end of season to improve soil.
Leaves (fresh)
Shred before using if you want them to break down faster.
Use layer 5 to 10 sheets thick. Disguise with thin layer of attractive mulch.
Turn under at end of season. Adds nutrients. Store-bought stuff looks and smells less like the real thing.
Compost Used manure left after mushroom harvest. Can turn over at end of season to improve soil. May contain pesticide residues. Texture is too fine to suppress aggressive weeds.
Peat Moss
Use 1-2 inch layer near acid-loving plants. Soak in warm water before using. Never let it dry out completely or it will shed water. Use Canadian peat; Louisiana peat may be dangerously acidic.
Pine Needles
Regional product. Last two to four seasons. Pine trees provide ready supply.
Use at base of flowering shrubs. Get kind that lets water pass through. Top with more attractive mulch.
Breaks down quickly. Depletes soil nitrogen, so sprinkle soil with blood meal or other nitrogen source.
Loose layer about 6 inches deep, will settle down. Lasts one to two seasons. May deplete soil nitrogen.
Wood Chips
Byproduct of timber industry. Quality varies. Recycled woods from pallets and construction may contain toxins that kill plants and contaminate soil. Don’t use chips if they smell sour; this indicates the presence of harmful acids. Rid fresh chips of acids by letting them decompose in a compost pile before using.


Well there you have it friends. Garden Mulch 101. Whew, quite a bit of info but easy to assimilate and put to good use, eh? Let’s Get Outside and Get R Done!

Paradise Restored Landscape & Exterior Design welcomes your visit our gallery of works:

If you’ve been thinking about a landscape transformation, contact us for your Complimentary Consultation @



As usual my friends, thanks for stopping in!

Get Outside – Enjoy our Indian Summer before Winter Hits

Kim Thibodeau, Exterior Design Services

Landscape Blogger, Not a Big Fan of Red Bark Mulch




Comments are closed.