Top Landscape Maintenance Questions–Why We Do Not Recommend Rock Mulch or Landscape Fabric

Recently we received an inquiry about maintaining flower beds. The homeowner had finally gotten control over her unruly yard by putting down landscape fabric and gravel mulch in all her flower beds. Weeding took 5 minutes, so that is a win, right? Unfortunately, these are short term solutions that will result in long-term problems.

Nature helps us understand. On a forest floor, dead plant materials decompose and this compost is naturally churned back into the soil by insects and animals. This cycle keeps the soil healthy and plants thriving. Landscape fabric prevents composted mulch from being reincorporated, greatly reducing the fertility of the soil. A garden we recently renovated had 7 layers of landscape fabric. What was revealed below all those layers was a sticky clay that desperately needed an infusion of organic material. No wonder the plantings were stunted.

Double shredded hardwood mulch will decompose into a lovely compost, which we’ve all seen weed seeds flourish in. Hence our homeowner’s decision to use rock as mulch. No germination going on there! The seeds are fried by the sun and the lack of water. Unfortunately, this will also affect the plants she wanted to maintain. Because an organic mulch contains water, it helps even out the extremes of winter and summer. It acts as a temperature buffer, keeping roots warmer in winter and cooler in summer. It also keeps the plants hydrated during periods of drought.

So how to deal with the weeds that flourish in an organic mulch? Here are a couple suggestions:

If the bed is completely overrun, consider starting from scratch. This can be accomplished by using black plastic or herbicides to kill all the plants, then amend the soil with a high quality compost (not manure, which will contain viable weed seeds.) It’s important to purchase mulch, compost and plants from sources that are not contaminated with diseases or weeds. If you’ve used landscape fabric, pull it all up before amending the soil with compost around the plants you want to keep. Using preemergent herbicide (like Preen) in the early spring, and then periodically over the year.

Mowing frequently will reduce the number of blooming weeds nearby. Using an edger machine on your flower beds will prevent grass from creeping in. Ultimately, some weeding will be required. Consider reducing the size of your garden and using an English style planting to help squeeze out weeds. One well-tended bed will have far more visual impact than a yard full of untidy plantings.

Local nursery we recommend? Check out Windmill Heights in Culpeper, owned by fellow VT horticulture graduate Paul Hutcheson. Their website is <em><strong><a href=”” target=”_blank” rel=”noopener”></a></strong></em>. Need professional landscape design and construction? Reach one of our Landscape Architects at 540-825-7570.