Moss Madness: Go to war with Mr. Moss or let him be — the choice is yours

By Trevor Cameron / The Golfing Gardener

In the maritime Pacific Northwest climate, mosses have invaded and naturalized almost all of our native habitats, in one form or another. Our Western Washington locale provides Mr. Moss with his three favorite things: plenty of shade, regular moisture and soil acidity.

Many gardeners embrace these soft and cushy creatures, admiring their colors and low maintenance qualities, while others think of moss as some sort of plague that never ends. This month is the perfect time to either go to war with Mr. Moss or let him be, flourishing wherever he wants.

Consider the nature of true mosses with the simple fact that they have literally had our fine planet as a habitat for around 400 million years. Prehistoric bryophytes, such as these, are from the beginnings of the plant world on Earth. Mosses have certainly evolved over the eons that they’ve existed, and they continue to flourish across the globe today. Right here in Western Washington, you can look almost anywhere and see sheet mosses, clumping mosses, hanging mosses and even mosses (or close relatives) sold at local nurseries that make nice foot-traffic-tolerant ground covers.

Now, being the OCD golfer that I am, I simply cannot have excessive amounts of moss in my own turf, or on putting greens for that matter. You can make your own choice of course, and if it suits you, then let it be. Coming out of winter in March, you will see moss everywhere in the turf, and if left unchecked, it will continue its invasion throughout the spring.

For turf areas, gardeners can grab a granular moss killer (typically containing iron in some form) and broadcast it using a simple spreader. Grasses can absorb a massive amount of iron and simply turn a darker green, while moss cannot tolerate it and thus turns black and perishes. This may be a little bit more of a time saving and economical choice for many gardeners, but be careful not to get the granules on other surfaces as the iron will stain concrete, wood, rock and most other surfaces. Care should also be given not to get this on plant foliage, as it may burn and damage leaves.

The other option is a liquid application, which may take a little more time to apply with a hose-end or pump sprayer, but it allows you to focus the treatment on specific mossy areas. Liquid moss controls with iron are out there as options, but I would suggest a product such as MossMax liquid from Bonide. It comes in a handy spray bottle and offers a natural option containing potassium. Your moss will turn a straw-yellow once dead, and without the metals in this product, it can be applied directly onto patios, walkways, siding, wood or just about anywhere safely without any staining. This is the one product that can also be safely used on actual plants, as well — but only on deciduous specimens when they are dormant in winter.

I think mosses and lichens add character to older trees and shrubs and typically do not cause any issues. Some gardeners, however, do not agree, and in winter this potassium product could be applied to bark and branches. But let me be honest, we are in Western Washington and the moss and lichens will definitely be back at some point.

If you take the time to treat the moss, make sure to rake or thatch it out once it has died. March is the perfect month to thatch your turf, which will remove this dead moss and all of the thatch build-up, allowing you to essentially start over.

After an adequate thatching, lots of bare ground will be showing, which is a good thing. If you sprinkle some fresh local grass seed, organic lawn food and dolomite lime and then cover it all with a thin layer (⅛-inch to ¼-inch) of compost, you are on your way to rejuvenating your turf for the season.

Organic lawn food is the superior and safe fertilizer choice, adding to the food web in the soil and providing beneficial sources of magical compounds, such as humic acid. It will also never burn anything, even fresh grass seed. An annual dose (or sometimes in both spring and fall) of lime is of huge benefit as well to the turf. With our native soil being acidic, the lime will simply help raise the pH level in your lawn. Since moss loves acidity and turf thrives in a more neutral to alkaline soil, you are reducing your potential of moss significantly and helping to create a better soil for the turf to thrive in. I do this for my lawn in the spring and fall, and the amount of moss I have to deal with now is a fraction of what it once was, for sure.

Hopefully you will consider mosses in parts of your own landscape, and whether or not to keep them here or stop them there. Visit your local nursery and talk with a professional horticulturist about your options, and hopefully they (like me) will explain that the lawn does not have to be a chemical depository in order to look sharp. Going green with quality organic products is easy and effective — simple as that. A healthy, safe and natural moss-free lawn is certainly possible if you put in some effort and follow these simple steps.

Free class

Sunnyside Nursery in Marysville will host “Cool Crops: Early Season Veggies” at 10 a.m. on Saturday, March 16. For more information or to sign up, go to www.sunnysidenursery.net/classes.

Trevor Cameron is a certified professional horticulturist (CPH) and serves as general manager for Sunnyside Nursery in Marysville. He can be reached at sunnysidenursery@msn.com.