Landscape fabric, mulching & fertilizer, oh my!

Lindsay Bourque of LIMINAL DESIGN + YARDWORKS answers some of your burning garden questions.

Wood chips make a great mulch and are easy to come by in this town. Photo Credit: Lindsay Bourque

This article first appeared in print in the August, 2018 issue of Revelstoke Mountaineer Magazine.

Summer is in full bloom and it is a busy season – I’m getting lots of questions about garden maintenance so I thought I would answer some of the most common this month.

Landscape fabric: Yea or nay?

I get it, it’s difficult to let go of the promise of permanent weed suppression – but landscape fabric is not an effective long-term weed deterrent and can also have detrimental effects on the health of your soil. Firstly, organic matter will still accumulate on top of the fabric, creating prime growing conditions for air-borne annual weed seeds. Additionally, landscape fabric will do nothing to supress our more thuggish invasives like horsetail and knotweed.

The barrier also prohibits decomposition of your mulch layer, a necessary process in the health of your garden and, if you have ever renovated a fabric-covered garden, you know it makes even minor changes infinitely more difficult.

Speaking of mulch, what should I use?

Stone is a common ‘mulch’ in Revelstoke – it looks great but requires more maintenance hours to properly top-dress.

My first suggestion is always to try and use the resources you have available. Know someone with a wood chipper? Wood chips make a great mulch (a note about chip size: you want to shoot for small-medium chips; too fine or too coarse, the chips will fail to decompose).

We are lucky to have mature trees in our urban forest, and they provide us with ample material to help condition the soil. Make an area in your yard to make leaf (and needle) mould; well-rotted leafmould (more than two years old) can be used as seed-sowing compost or mixed with sand and quality soil to use as garden or potting compost. If you have a lot of pine on your property, make a separate pile for the needles – they will create an acidic leafmould and is great for many of the plants that do well here (for example, ericaceous plants like rhododendrons, azaleas, etc).

However, I believe that plants make the best mulch and try and encourage clients to use groundcovers. As Claudia West, co-author of “Planting in a Post-Wild World” points out, one of the core principles of the natural world is that plants cover soil and refers to mulching a “perverse tradition.”

When should I fertilize?

We all need to eat, right? A biannual compost top-dress in the spring and fall will pay huge dividends down the road. If you are using a slow release granular fertilizer, you’ll also want to spread it in the spring. These fertilizers will feed plants for 3–6 months and by this time of the year should not be used anymore – it can disrupt the dormancy cycle in plants and push new growth into late fall, sending energy into new shoots instead of into the rootstock, where it is stored for the following spring push.

People tend to overfertilize if they see a plant in distress, which can cause more harm – think of fertilizer like food, not medicine.

I don’t want to do any maintenance or irrigate my garden, what should I plant?

Artificial plants?

One of my former landscape bosses pushed this point one year at a xeriscape demonstration garden show: much to the horror of the Sunday garden crowd, he lit a bunch of spot fires in his installation to “demonstrate” how we are creating tinder boxes by pushing the idea of waterless gardens. He was never invited back to the garden show but I think he said everything he wanted to say. Mic drop.

There is a myth that native/drought tolerant plants don’t need to be watered – as a general rule, all plants will need to be watered for the first couple growing seasons, even if we are having a fairly rainy spring/summer like we are experiencing now.

As for maintenance, no garden is maintenance free – it is an extension of your home and, just like the building that sits on the land, the yard will require routine maintenance to remain serviceable.

Lindsay Bourque has been working in the landscape trade for over a decade, first as a gardener/landscaper then earning her master’s degree in landscape architecture at UBC. Since then, she spends more time on a computer, but Revelstoke allows her to keep a foot in both design and construction – and both feet on a board as much as possible.