Gene E. Bush is a shade garden expert, garden writer, photographer and speaker. Visit his website at shadegardenexpert.com.

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What Are Nurse Logs?
by Gene E. Bush       #Beneficials   #Environment   #Shade

This hollow log was turned on end and filled with a mix of gritty composted pine bark. Moss and walking ferns were transplanted in it, and take care of themselves.


Being a gardener in shade, I have long been fascinated by logs. I have admired them in nature since childhood. There is something about the sight of one that draws me to it for a closer look; wanting to know about its past life as well as investigate how it keeps on giving even as it takes on a new life. However, it has been only in the last 5 years or so that I have begun to bring “nurse logs” into my garden.


This hollow beech tree will become a nurse log in the shade garden.


Natural Cycles
While alive, deciduous trees shed leaves to decompose beneath their branches, and in death they still keep on giving. Almost from the moment they fall to the forest floor, fungi begin to feed upon the log, slowly creating duff. As the log ages, insects move in to feed upon the decay. Roly polies (aka pillbugs), grubs, worms and beetles move in to dine, creating tunnels from log to soil enriching the surrounding area. In turn, the insects become dinner, as their colonies grow, for small mammals such as raccoons and skunks. Birds flock to the log to search for their next meal. As birds, insects and mammals take the log apart to get at the insects, the log is returned to the soil to become food for the next generation of shrubs and trees — plants of the forest floor.


Nurse Logs
Fallen logs often decompose to form containers in the decayed wood. Often you can see seedlings of trees and shrubs sprouting from the log. Given a large enough fallen tree (and time) you can often see how a row of trees has formed from being nursed and tended inside the log. In a shade garden, they can become even more than nature intended.


Design
Nurse logs in the shade garden provide a design element that is relaxed and natural. Depending upon the size of the log, it lends mass without seeming man-made. It becomes a feature that adds to, but does not detract from, the plants. The decaying logs become containers for tricky, hard-to-grow perennials and vines.

When moving a log to my garden, I dig a trench to match the length of the log. I also want the trench to be about one-third the diameter of the log. With some of the log buried it can wick up moisture and stay damp. I also like to mulch around the log with chopped leaves to add to the natural appearance.

I often use a mix of potting soil and pine bark fines as a growing medium inside the log where small ferns and shade-loving perennials are elevated, and thus closer to the eye.


This cedar is visited by woodpeckers frequently.
 

Since I garden on the side of a hill, water flow can sometimes be a problem with washouts. Strategically placed and dug-in logs are very useful in slowing and redirecting water flow.

When considering design elements for my garden, I like to include features not only for my ornamental design but also for the environment. I enjoy the wildlife a buried rotting log brings to my garden. My most prized visitor is the pileated woodpecker (Dryocopus pileatus) who comes to the garden each day to dine on his favorite log.


How Long Will it Last?
Some logs will have a longer life in your garden as a design element than others. Pine logs usually last about 4 or 5 years for me. Cedar decomposes very slowly. The size of the log and how decomposed it was when you obtained it helps to determine how long it will last as a feature. I usually count on 5 years when locating a log of any size to my garden.

I have been using logs in my garden long enough that my gardening friends check with me before discarding a fallen tree or large limb. Sometimes after a local storm there is an abundance of downed trees to select from. If you live near a river, there is always the option of collecting driftwood logs. Just make sure you have assistance when moving a log to your garden.
 

Moss on a nurse log in the shade garden. • Viola walteri ‘Silver Gem’ with Asarum virginica in the hollow of a buried log.
 

This colorful fungus is one among many that adds color to an aging log.


Favorite Companions
Among my favorite companions for my logs is moss. One of the first transplants to a new log is moss: Relatively quickly it gives the illusion that the log has been there forever. It also adds contrast between the hard wood, and the colors of brown and black, against the softness and green of the moss.

I find small ferns such as the walking fern (Camptosorus rhizophyllus) fascinating when grown in the log with mosses. Oak ferns (Gymnocarpium dryopteris) make perfect drifts along the outside of the log wandering between and around larger perennials. There is no end to larger clumping ferns, both native and non-native, to select from as companions.

If I could have only one vine to grow in my aging log it would be the partridge berry (Mitchella repens). This well-behaved small vine is a ground-hugger of tiny rounded, shiny, leaves with silver stripes down the center. Flowers are twin trumpets of white that become scarlet red berries.

Native woodlanders I look forward to each spring in my garden are toadshade (Trillium spp.), bloodroot (Sanguinaria canadensis), Jack-in-the-pulpit (Arisaema triphyllum), dwarf crested iris (Iris cristata) that forms a ground cover, and Canadian ginger (Asarum canadense). Hepatica spp. clumps are treasures of quiet color and silver-kissed fuzzy foliage. Viola walteri scampering about in the log is a gem. Notice that I choose to stay on the quiet side of colors when choosing companions for my logs.

Non-native choices as nurse log companions are the ubiquitous Hosta in small to medium size named varieties. Barrenwort (Epimedium spp.) are a must for ease of growth and a tough but attractive ground cover. Toadlilies (Tricyrtis spp.) are favorite perennials for their intricate orchid-like blooms of late color. For very early color and 12-month foliage Helleborus hybrids will fit nicely.

 

A version of this article appeared in a November/December 2015 print edition of State-by-State Gardening.
Photography courtesy of Gene E. Bush.

 

Posted: 11/14/18   RSS | Print

 

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