I have learned over the years that commercial (sold in bags or delivered in loads) garden soil and mulch are not the most efficient products to improve the quality of soil in your garden beds. Every time I have done so, I end up with more weeds in my gardens…
So, if you shouldn’t use the commercial garden soil and mulch in your gardens, what should you use? Instead of the commercial garden soils and mulches that are available in bags from your local garden center or delivered in truck loads, I currently use the following plan.
In the fall I use shredded leavesas a mulch throughout my gardens, then in the spring, I spread composted manure around all my emerging plants. Be sure to use well-composted compost or manure in this step to avoid stinking up your neighbourhood. The extreme heat levels in the composting process kills weed seeds too, so is very important. You could use your own compost pile, but ensure it has matured to the weed free level. For large volumes, I use this variety (available at Home Depot) of composted cattle/steer manure, particularly because it does smell bad:
This process adds both nutrients and humus to my existing soil, improving its quality immensely. The proof is in the beautifully healthy looking plants and lack of weeds!
When all the pretty leaves fall from the trees this fall, instead of bagging them to put out on garbage day, use them in your garden as free mulch. Most leaves, with the exception of oak leaves, break down easily over the winter. They add nutrients and humus to the soil in your gardens.
If you do not have a leaf mulcher like I do, you can break (mulch) the leaves up by running them over with your lawn mower while they are still on your lawn. Then rake the debris onto your garden between the plants. Your soil and plants will love it.
This is another rant, based on a pet peeve of mine. I advise gardening clients to use mulch to keep their gardens from drying out and to help reduce weeds. The problem is, some products out there are full of weed seeds, so when I go back to check out gardens two weeks after planting them I see more weeds than were there before I planted! A dead giveaway is that each use of mulch seems to have its own species of weed, today’s was horsetail weed mixed with a coarse grass:
This is not the first time this has happened with this particular brand of mulch. I will be contacting the manufacturer of Scotts Nature Scapes to complain and will avoid this brand from now on.
Too bad, because I do like their choice of colours, and the colour does not fade in the sun like some other brands. My favourite is the dark brown as it looks like wet earth so I think the most natural looking. I also like the size of their bags, big enough but not too heavy for me to load, unload and carry from my van to my gardens.
If anyone can recommend an alternative (weed free) brand (available here in Ottawa) for me to use and recommend to my clients, please let me know! I do use a lot of mulch in a season!
The cool, wet weather we had last week was great for weeding gardens. Without removing the whole root system of the weeds, they will quickly return to spoil your gardens. After a hard rain, it is much easier to remove the weed roots intact…
A well-mulched garden also makes it easier to remove weed roots intact. Weed roots growing in soil seem to resist removal, often breaking off in the soil, leaving pieces of the root behind to continue growing. When growing in mulch, the weed roots come out intact with much less effort.
Fallen leaves make great mulch and compost for your garden, protecting your perennials as well as improving the condition of your garden soil. Instead of raking the leaves up and taking them to the curb in lawn waste bags, consider using them to your advantage this fall.
If they are small leaves, simply rake or blow them into your garden around your perennials and shrubs, taking care not to bury the smaller plants. If the leaves are large, run them over with your lawn mower to shred them before adding them to your garden. Oak leaves especially should be shredded, as they are slow to decompose. You may have to spray the leaves with your hose once they are in the garden to keep them from blowing back onto your lawn.
In the garden, worms from the soil will draw the decomposing leaves into the soil, improving the condition of your soil, which in turn benefits your plants. Next spring you can bury the portions of leaves that have not decomposed in the garden, and marvel at how rich your soil is.
The leaves in the garden will also protect your perennials and shrubs, like a warm blanket, from the freezing and thawing cycles that do the most damage to garden plants. Roses especially benefit from a blanket of leaves around their crowns at the soil level.
Leaves should not be left on the lawn however, as they will smother the grass, ruining even the healthiest lawn.
So, when you are out raking the leaves off of your lawn within the next few weeks, save your money by forgoing the lawn bags and turning the leaves into compost and mulch.
Sometimes I advise clients to use mulch in their gardens, and sometimes I advise them not to, but most often I advise them to use it wisely. Why? Because many times mulch is used for the wrong reasons and incorrectly, causing more harm than good…
Mulch is beneficial for keeping moisture in and keeping weed levels down, but it must be applied properly. Applied incorrectly, too thick or too close to plants, it can cause rot, mildew/mold and eventually the demise of your perennials, shrubs and even large trees.
Mulch should not be piled right up to the base or stalk/stem of your plants. When applying mulch to your gardens you should leave a space of at least 1 inch (so the soil shows) between the base or stalk/stem/trunk of your plant or tree and the mulch. After a heavy rain and in the spring after snow has moved the mulch, you should reestablish this space as soon as possible, especially for young plants that will rot quickly if the mulch is left too close to the stems.
Mulch applied too thickly around the base of a tree will eventually kill the tree. The roots of all plants, including large trees, require oxygen, moisture and nutrients. If mulch is applied too thickly, these required items cannot reach the roots, causing starvation and death of the plant. This theory also applies to ornamental rocks and anything else piled around trees to minimize the growth of weeds and grass. These pictures show mulch piled much too thickly around the base of a mature tree(incorrect), and removed from the base and spread out (correct):
mulch applied too thickly (note the demarcation line on the trunk)
mulch removed from tree and spread out
Mulch will keep weed levels down, but it will not eliminate weeds altogether as many people are led to believe. Weed seeds blow in the wind and will settle in the mulch and germinate there too. The difference is, when you pull out a weed growing in mulch, it comes out much easier and more completely, with the root intact. If you do not remove the entire root of a weed it simply grows back, often very quickly.
Mulch applied in a thin layer (one inch thick is plenty) around a tree can be beneficial to keep weeds and grass roots from competing with the tree roots for oxygen, moisture and nutrients. Just remember, more is definitely NOT better!
Nothing, including grass, should be planted around a new tree for the first five years, allowing the tree roots to get established. After that, shallow rooted perennials or annuals work best as they do not force the tree roots to compete for required elements. A few examples of shallow rooted perennials are geraniums, sweet woodruffe and lamium. My personal favourite is the perennial geranium (very different than the red annual geraniums that I am not so fond of) because it tolerates almost full shade to almost full sun, and is the first plant to green up in the spring. Perennial geranium flowers can be white, pink, blue, purple and many shades in between, but are almost inconspicuous in many of the varieties; the foliage is the main attraction to me:
If you do decide to mulch your garden or use mulch under your trees, please use caution and apply it correctly so you do not do more damage than good…
I have finally completed this garden renovation. I started working on this large garden late last summer; it was full of overgrown perennials (mostly huge hostas and fall sedums) weeds and grass. It took a week and a half just to get all the overgrown plants out and divided. I had to enlist the help of my son to help dig out some of the large hostas as they were close to four feet in diameter! The sedums were not much smaller.
As I hate to throw any plants out, I used most of the hostas along the walkway into the client’s backyard, planted among the riverrock at the edge of the sidewalk. They survived the winter and look great this spring.
Although I got caught in a few thunderstorms and had to run for cover, the wet soil was ideal for planting a variety of new perennials and transplanting the ones I wanted to keep.
I was surprised that all of the plants survived the harsh winter we had. This spring I dug out the new crop of weeds and grass, then covered the exposed soil around the well spaced plants with a nice thick layer of mulch. I use cedar mulch because I love the smell of it, especially when you are watering the garden. I prefer the dark brown or black color of mulch because it is closest to the color of earth in a freshly watered garden. This mulch will help keep the weeds out of the garden and keep the plants from drying out in the hots days of summer.
I look forward to visiting this garden next season after the plants get a chance to spread out into their new homes. Spacing them well apart now will ensure they do not end up in another overgrown, jungle-like setting any time soon.