Because water passes through the landscape fabric under your rocks, holes in it need to be only large enough to fit around the bushes’ trunks. Cut lines in the fabric from its sides nearest to the holes for the trunks, so you can wrap the fabric around them. Covering the fabric with rocks helps hold it in place, although placing landscape staples every 2 feet or so along each edge of the fabric also helps.
A post-emergent herbicide kills weeds as soon as they sprout. Choose a non-selective herbicide such as one containing glysophate so it will kill nearly any kind of weed that appears. Care is essential when spraying the non-selective herbicide near your bushes because it can harm or kill bushes as well as weeds. Protect the bushes from herbicide drift by placing plastic or a large piece of cardboard between the bushes and where you spray, and spray only on days that aren’t windy.
Adding underlayments between the rocks and the soil creates a weed barrier that helps prevent weed seeds from touching the soil. If you already have rocks in place, rake them away temporarily while you install the underlayments. Choose landscape fabric or black plastic as the underlayments.
Best Weed Barrier Under Rocks
Rocks, including river rocks and gravel, commonly serve as mulch to help keep weeds from finding a home in flowerbeds. When you cover a rock garden completely in rocks, you have built-in mulch support. Whether your garden has large boulders as part of its design or is low and flat, using color and texture for design, ensure the area is covered completely with small rocks serving as mulch. Scrape the rock mulch about 2 inches away from the trunks of the bushes to help prevent root rot and other fungal infections.
Plastic is the best weed barrier under rock, but water won’t pass through it to feed the bushes’ roots. An option is to use the plastic, but leave large holes in it around the bushes. Alternatively you can combine the underlayments, placing landscaping fabric around the bushes and then covering the rest of the rock garden with heavy plastic. You’ll still leave holes for the bushes, but that space will be weed resistant because of the landscaping fabric.
The Chemical Herbicide Option
A rock garden adds texture and color to a difficult area of a yard, such as a hillside, and it serves as a focal point. Adding bushes to a rock garden adds a touch of plant life that doesn’t require constant upkeep. When weeds pop up between the rocks, they mar the garden’s appearance, but one or more weed-control options – most notably, landscape fabric under the rocks – can be used to restore the site.
Pulling weeds by hand is a traditional way to handle them organically, but other options exist that are easier on the back. Pouring boiling water over the weeds burns their leaves and kills the plants, as does pouring vinegar on them. Although salt is effective as a weedkiller, don’t use it in a rock garden that has bushes. Salt changes soil salinity and could kill your existing bushes while keeping future ones from growing.
The best long-term solution for your weed invasion is landscaping fabric. If you are planning on building a new rock bed in your backyard, or plan on renovating the old one, don’t hesitate to lay down landscaping fabric first.
A quick and natural way to kill weeds in rocks is by pouring boiling water directly on them. The scorching water will burn the leaves and kill the plants immediately.
Use this natural weed killer to spot-treat weeds. Make sure not to get any on your precious flowers.
Sprinkling rock salt directly on the soil doesn’t give you enough precision. Precision is critical when working on rock gardens adorned with decorative plants. The root systems of the plants may be reaching further than you think. You might be sprinkling salt right where the roots are.
Lay Landscaping Fabric
The landscape fabric will block the sunlight and keep weeds from growing. You won’t have to bother plucking the weeds ever again.
You’d be surprised how many people are dealing with this same issue. Weeds are just so stubborn they will grow even through rock, driveway, sidewalks, pavers, gravel, and mulch. It’s quite impressive, actually.
To kill the weeds, spray undiluted 5% household white vinegar directly on the weeds. Make sure they are completely saturated. White vinegar is non-selective, so be careful not to get any on the decorative plants.
Kill Weeds With Boiling Water
The most effective way to kill weeds in rocks is by using a weed killer.
Contact weed killers kill only above-ground parts of the plants that come in contact with the active ingredients. This type of herbicide destroys the seeds that lay on the soil as well, to prevent them from sprouting.