Monthly Archives: June 2012

Mulch – Use What You’ve Got!

 

If you grow vegetable gardens, you probably know that mulching around plants is essential – not only does a thick layer of mulch control weed growth in your beds, but it shades the soil, keeping it cooler and helping retain soil moisture during the dry spells of summer.

You don’t have to spend a fortune on bagged mulch, though. Look around. You might have materials that can double as mulch and save you money. Cut sheets of cardboard into long strips and lay them between rows of vegetables to cover the soil. Stockpile your dry fall leaves, and run them through a chipper or shredder to use as mulch for next year’s gardens.  If you bag your lawn clippings during mowing, use a few inches of clippings as a nutritious garden mulch that will also feed the soil as it breaks down. Important: NEVER use grass clippings from lawns that have been treated with Weed & Feed or other pesticides! You don’t want those chemicals in your food.

Get creative! Do you have anything growing that you could sacrifice for mulch? One plant growing in abundance here on our farm is hay-scented fern (Dennstaedtia punctilobula). This aggressive native fern takes over my planting beds, so I occasionally pull up armloads of the stems to keep the ferns from invading nearby garden areas.

Hay-scented fern makes an excellent natural-looking mulch!

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You can bundle small amounts of fern foliage together and fit them between rows in your garden. The green fronds dry quickly and unlike other weed plants, ferns won’t bring scads of unwanted seeds into your beds.

Below: the green fronds dry out and turn beige after a few days.hayscented fern tomato mulch IMG_0277

It’s easy to fold the stems into angles to neatly fit around each plant. Always keep mulch a few inches away from plant stems to prevent stem rot and the introduction of pathogens.

Another great “free” mulch is the trimmings from ornamental grasses when you cut them down to the ground in early spring. Dried stems and leaves make great mulch for strawberry plants or potatoes. I’ve heard of gardeners who grow large grasses just for the sheer bio-mass they produce, which can be used to feed compost piles too.

In the woods of New England, hay-scented fern colonizes areas of moist shade, such as this slope at our farm. There was once a garden here, but the fern has taken over completely:

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Below: Hay-scented fern growing out of our front steps. Yep – this is one of our most tenacious weeds…

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Do you have weeds that can play double-duty as garden mulch? I’ve been known to use the enormous leaves of burdock or squash as a temporary mulch around newly planted veggie seedlings to shade the soil. Be careful what you choose though – don’t pull up weeds that have gone to seed, and don’t introduce roots from weeds that spread through underground rhizomes (some field grasses and goldenrods) – they may root in your garden.

Groundcovers for Moist Shade

I’ve heard a lot of questions lately about substitutes for the ‘old standby’ shady groundcover plants Japanese Pachysandra (Pachysandra terminalis) and Periwinkle (Vinca minor). Both of these imports have been used for generations for the shady blanket effect under trees, but for nature-friendly gardeners who want to increase biodiversity in their yards, these plants offer very little value to birds, beneficial insects and soil health. Not to mention, but they can also become invasive in moist woods where they spread out of control – read about my ongoing battle with Japanese Pachysandra.

Here are some suggestions for native groundcover plants for New England to replace the invasives:

Running Foamflower (Tiarella cordifolia) – this is my all-time favorite native New England groundcover. In early May, it’s covered with a sea of soft white gasp-inducing blooms:

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The rest of the year, its foliage forms a nice weed-suppressing mat – as long as it’s grown in moist, rich woodland-type soil. An area under deciduous trees where leaves and duff are allowed to build up in the soil is ideal.

Wild Ginger (Asarum canadense) is an essential component of New England native plant gardens as green “filler” to weave in and around larger plants – forming a living mulch that keeps the soil cool and prevents weed formation. Its dull-red flowers form in early spring – at ground-level to cater to ground-dwelling pollinating insects.

Shown below at the right of the photo, the heart-shaped leaves of wild ginger mingle beautifully with ferns and other woodland plants – remaining green and lush after the spring ephemerals are long gone:

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Another native plant that will quickly cover a moist shady area is Mayapple (Podophyllum peltatum), shown here growing under oak trees at Garden in the Woods in Framingham MA:

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Mayapple will dominate surrounding plants, so give it an area all its own where it won’t dwarf its neighbors.

Bunchberry or Creeping Dogwood (Cornus canadensis) is a native woodland plant with late-spring flowers that look like small dogwood blossoms:

bunchberry IMG_7493Bunchberry is late to fully form its foliage in the springtime, so it’s not as effective at suppressing weeds at Pachysandra, but if grown in a cool, damp soil, it will happily spreads into large patches that can be occasionally mowed to keep other weeds at bay.

Last but not least, did you know there is a Pachysandra native to the eastern US? Allegheny Spurge (Pachysandra procumbens) grows wild in rich woods from West Virginia and Kentucky south to Louisiana and Florida, but it is quite hardy in most of New England (to zone 4). It’s semi-evergreen (unlike its evergreen Asian cousin Japanese Pachysandra) with spring flowers that smell like cinnamon:

pachysandra procumbens IMG_9972In my experience, Allegheny Spurge needs consistent moisture in its first few years, but becomes quite drought-tolerant once established. It’s most happy with some summer shade in New England, and spreads nicely from clumps rather than the aggressive underground runners of the Asian variety which invade moist woods here in Massachusetts.

Native wildlife gardening purists might disagree with using a southern native in the northeast where it’s not traditionally indigenous, but as average temperatures continue to rise in the coming decades, we may find that growing southern species here in New England will support their co-adapted pollinators and other specialized insects as they migrate north in an effort to survive. As we struggle to maintain biodiversity in an era of mass species extinctions, these kinds of assisted migrations may become essential…