I’ve seen it again and again. Helping a friend renovate their garden, I dig down a few inches and my shovel becomes entangled in a sheet of black plastic or some other material, collectively known as landscape fabric. Oh boy. Another case of pie-in-the-sky magic weed barrier.
“What’s this?”, I ask. “Weed barrier.” “Really? Then why are there foot-tall weeds in your garden?”
One of the great gardening myths is that landscape fabric will suppress the weeds in your garden for years. Sold under many trade names and made from an assortment of materials, from plastic films to renewable sources, weed barriers are sometimes impregnated with herbicides and fertilizers.
An experienced gardener learns that weed barriers defy logic, strangle plants, and decimate soil. Weed seeds largely move by air or animal. They are deposited in the mulch or organic material on top of the weed barrier—mulch that doesn’t decompose as it should because the weed barrier doesn’t allow it to contact the soil.
Now, to be fair, landscape fabric has its uses. It was developed for commercial agriculture, and it’s highly effective in that capacity. But it’s less than useless in perennial home gardens and can actually do a lot of damage to your plants and soil.
Will Bulbs Grow Through Landscape Fabric? The Truth About Using Weed Barriers in Gardens
Landscape fabric, also known as weed barrier fabric, is a popular tool for suppressing weeds in garden beds But how does this fabric affect bulbs planted in the same areas? Will daffodils, tulips, and other bulbs be able to grow through the fabric?
The Purpose of Landscape Fabric
Landscape fabric is a woven or nonwoven polypropylene material that is laid atop the soil before mulching. It serves several useful purposes:
- Blocks most weeds from germinating and emerging
- Prevents existing weeds from poking through the mulch layer
- Conserves moisture by preventing evaporation
- Controls erosion by keeping soil in place
The key benefits come from landscape fabric’s ability to block sunlight and smother weeds before they can establish. At the same time, water and air can penetrate the fabric to reach the soil and plant roots below.
The Downsides of Landscape Fabric
While landscape fabric seems like a garden miracle product, it does have some downsides:
- Deteriorates over time and may need replacing
- Can prevent moisture from soaking into clay soils
- Makes it difficult to plant new plants without cutting holes in the fabric
- May cause soil compression and poor aeration
- Can harbor voles and pine mice who chew through and nest under it
Careful consideration should be given before using fabric over entire garden beds. It may be better suited only to pathways and areas with established plantings.
The Effect on Flower Bulbs
Here’s the crucial point – landscape fabric will prevent bulbs from growing properly if placed above them. Flower bulbs produce roots and shoots that need to emerge upward through the soil surface each year.
Fabric and other solid barriers over the top of bulbs can cause them to rot and decline over time. Their natural growth process becomes stunted.
Some light penetrating fabrics may allow very limited shoot growth, but this is not ideal and will severely limit the plants. Overall landscape fabric is incompatible with the seasonal growth habits of bulbs.
How to Plant Bulbs Through Landscape Fabric
While landscape fabric prevents natural bulb growth, it is still possible to plant bulbs in areas with the fabric in place. Here are a few options:
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Cut an X-shaped slit in the fabric and plant the bulb through the hole beneath. Make the hole large enough for foliage and flowers to emerge.
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Layer newspaper or cardboard over the fabric before planting bulbs. The paper will decay allowing shoots to emerge.
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Use a gravel mulch rather than bark or leaves. Shoots can push through gravel more easily.
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Choose bulbs with very sharp foliage tips that can penetrate fabric, like tulips or daffodils. Avoid rounded shoots like hyacinths.
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Consider removing sections of fabric altogether and replacing with mulch once bulbs are planted.
Even using these approaches, growth may be limited and flowering reduced. Best practice is to avoid using landscape fabric where you intend to regularly plant bulbs each year.
Natural Weed Control Options
While landscape fabric is unnecessary when planting bulbs, controlling weeds is still important. Here are some non-fabric solutions:
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Mulch heavily around bulbs to block light from reaching weed seeds. Replenish mulch as needed.
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Maintain a layer of dense, competitive groundcover plants like sedums between bulbs. This helps suppress weeds.
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Carefully hand pull or hoe any weeds that do emerge. Be gentle around emerging bulb foliage.
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Use corn gluten meal, a natural pre-emergent herbicide, to prevent annual weeds. Apply in spring and fall.
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Try DIY vinegar-based herbicidal sprays on young weed seedlings. Reapply frequently.
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Sprinkle salt directly on problem perennial weeds such as dandelions to dehydrate and kill the roots.
The Takeaway
For the best results planting flower bulbs, avoid using landscape fabric atop the planting areas. While it is possible to plant bulbs through holes cut in the fabric, growth will likely be diminished. Rely instead on heavy mulching and vigilant weeding to control weeds while allowing bulbs to emerge naturally each spring. With a little diligence, your garden can flourish fabric-free!
Aesthetically speaking, when the weed fabric is exposed, it looks just awful – horrendous, ghastly, dreadful.
Did I mention how bad it looks when the mulch slides off?
Many of the old weed fabrics aren’t water and gas-permeable.
I’ve frequently seen soil beneath and above old weed fabrics dry as a bone and compacted hard as cement, the color of baked clay. The shrubs and flowers were starving for nutrients and struggling to find water, slowly dying, even with layers of compost and mulch on top. With little to no water penetration into the soil or gas exchange at the surface, little soil food web activity occurs. This is immediately apparent by the distinct lack of earthworms and insects just below the surface. Conversely, when used in very wet or soggy areas, the weed barrier can trap water beneath it, creating a swampy mess.
BIGGEST Weed Fabric MISTAKES We’ve Made!
FAQ
Will plants spread through landscape fabric?
Perennial flowers can grow through landscape fabric if the fabric is permeable. That means that the fabric allows water, air, and nutrients to pass through and reach the roots of the plant. If the fabric is non-permeable, it blocks the flow of these essentials and the flowers will not be able to grow through it.
Will bulbs grow through ground cover?
Bulb shoots are adept at finding their way up through low groundcover plantings, such as commonly used vinca (Vinca minor), sweet woodruff (Galium odoratum), deadnettle (Lamium), leadwort (Ceratostigma), and creeping sedum.
Can plant roots penetrate landscape fabric?
Once weeds start growing over top of landscape fabric, they can be quite hard to pull out. Often the root hairs penetrate the fabric and get deeply embedded.
When not to use landscape fabric?
Can you plant flower bulbs through landscape fabric?
Planting flower bulbs through landscape fabric can be a pain. While it is possible by cutting a hole in the fabric and planting the bulb in the soil beneath, animals like gophers can sometimes disturb the bulbs.
Can landscape fabric affect plant growth?
Yes, they can. But, landscape fabric may constrict the growth of plants. Not all, but many perennial plants will be inhibited from growing larger over time, because they have no room to expand. While we’re on the subject of soil and plant health, let’s sidestep here and talk a little about river rocks.
Can landscape fabric be used to transplant plants?
Landscape cloth is not conducive to planting new plants, transplanting or dividing existing plants. An area that has landscape fabric is a nightmare to plant in. You have to cut through the fabric in order to place new plants. Have you ever tried to transplant a perennial that is growing in a bed where landscape fabric was used?
Can perennials grow through landscape fabric?
Yes, they can. But, landscape fabric may constrict the growth of plants. Not all, but many perennial plants will be inhibited from growing larger over time, because they have no room to expand.
Does landscape fabric stop weeds?
The roots of the weeds grow through the landscape fabric making it difficult to pull them. Think about how many times you see weeds growing on gravel or in concrete cracks. If weeds grow in those places, landscape fabric will not stop them. Landscape cloth is not conducive to planting new plants, transplanting or dividing existing plants.
Do weeds grow in landscape fabric?
Eventually organic matter will accumulate on top of the fabric (even if the fabric is covered with river rock or wood chips) and it creates the perfect atmosphere for weed seeds to germinate. Also, weeds (especially dandelions) will eventually grow through the landscape fabric (see example below), both from the bottom and top.