What Does Grow Under Pine Trees? By Nancy Szilagyi

Everyone has seen those bare spots under pine trees.  Do you wonder why?  Perhaps you have heard that nothing likes to grow in such acidic soil.  The needles are thick under these trees. They must just make the soil too acidic for anything to want to live there. That’s what I thought.

Recently, I took an on-line class given by Dr. Tony Koski, professor at CSU and Extension Turfgrass Specialist.  I learned that our soil here in Colorado is very high pH--free lime.  Although pine needles fall in abundance, there could never be enough pine needles to lower the pH. Fallen needles may SLOWLY make the soil more acidic, but more likely for the better since it neutralizes the lime. It takes decades to change pH and will not decrease by more than .5 units. There goes that myth!

Following are the some of the real reasons many things, especially turf, don’t want to grow under these trees:

The turf tends to be smothered by a thick mat of pine needles.

Dense, year round growth leaves little light.  The only thing that will get through is ‘left over light’, according to Dr. Koski.  This light lacks     intensity and quality. This ‘left over light’ is what the tree does not use     for photosynthesis.

Any other plant will struggle with below ground competition—tree roots     competing for water and nutrients.  Our tree roots here in     Colorado tend to be fairly shallow.

Evergreens, with their dense growth, shed rain to the outside of the tree     line, so it’s dry under the tree. Without adequate water and nutrients,     most plants will suffer in this setting.

But, what does grow under pine trees?

 I have found a few things that for whatever reason, seem to work well under them.  The first is Brunnera macrophylla.  It has a couple of common names; False-forget-me-not, Siberian Bugloss and Heartleaf Brunnera. This one, my favorite, is ‘Jack Frost’.  It doesn’t mind the dense shade.  It doesn’t seem to mind the thick layer of pine needles around it, and the lacy blue flowers are dainty and beautiful.  After flowering is over, the stems can be cut back all of the way and you are left with the lovely heart shaped leaves for the rest of the season.

  The second, which I have come to count on, is Ceratostigma plumbaginoides, common name, Blue Leadwort. It, too, has dainty, pretty blue flowers, but it blooms later in the season than Brunnera. The flowers are followed by seed pods that look like little red tufts and are quite attractive.  The foliage is semi-evergreen and turns red in the fall. This plant is able to tolerate full sun to full shade!

  The third is Kinnikinnick.  This is a native plant in Colorado.  You’ll find it in the mountains growing quite happily along with all of the evergreens around it.  Kinnikinnick is more of a ground cover with evergreen, glossy, rounded, small leaves.  It blooms with tiny white and pink bells and shows off with pretty red berries in the fall.

All three of these plants will need additional irrigation, however, since lawn sprinklers and rain can’t reach them well, but it’s worth the extra time.

So, at least we know there are choices.  The easiest one would be to allow a natural mulch of needles to occupy that space, and that is just fine.  In fact, I find pine needle mulch quite attractive!  The other choice is to try one or more of the above plants, especially if you must have flowers in as many places as possible!

Vinca Minor, Free And Easy by Caroline Reardon

Do you have a shady spot in your yard that needs ground cover to hold back the erosion or to just cover a bare spot? If you or a friend are lucky enough to have a mat of thriving Vinca minor, you can easily propagate enough starts at home to solve your problem and save money to buy those spectacular plants you dreamed about over the winter.

Vinca minor, also known as periwinkle or creeping myrtle, propagates itself by putting out runners that take root in the soil, much as a strawberry plant does. You can use these runners to create healthy starts for those bare places in your yard. They will spread more quickly in areas that receive more water, and grow well in partial sun to full shade. An extra bonus‚this perennial remains evergreen throughout the winter.

 On the outer edges of the existing ground cover "crop" you will find the young, newly rooted Vinca runners which are the plants' most vigorous growers. Locate a clump and dig it up with your trowel. Shake it lose from the undergrowth and other roots and lift it out. Locate the clump's primary runner, which goes back to the mother plant, and snip it free with scissors.

You may find one clump can be snipped into three or more little rooted plants. Separate their roots, trim off any long stems and plant them in individual small pot with good soil mix.

Pinch off any flowers so all the plants' energy will be directed to developing good root systems in their new homes.

Water carefully so as not to disturb the roots and place the pots in a pan to catch any water runoff. Move them inside to a location with indirect sunlight.

 To keep their environment humid while rooting, cover the plants with plastic wrap. Mist them lightly every few days and check your little starts regularly to make sure the soil isn't drying out. Water if necessary.

 After about three weeks, gradually withdraw the plastic wrap and then take the plants to a shady area outside for several days to harden them off. Pop the Vinca out of their pots and transplant into the bare spots you'd planned for them, leaving  6"-8" between plants. Mulch to retain moisture and remember to water these little starts regularly for the first year as they get established.

Your home-grown Vinca minor starts will spread to become a lovely mass of shiny-leafed ground cover with periwinkle blue blossoms within a year or two, all for free.

Growing Hops for a "Native Lager" by Duane Davidson

Jeffco and other area gardeners who enjoy a cold brew on a warm day must have been intrigued by an article in the Denver Post recently. The headline and sub-head: "People's beer: AC Golden asks customers to grow hops and contribute them to its Colorado Native Lager, and 373 fans jump on board." Read it at http://www.denverpost.com/business/ci_16851639 .

The article explains that AC Golden Brewing Co., a small-batch unit of MillerCoors, brews a beer called Colorado Native Lager, "ostensibly made with all Colorado ingredients." But in truth it is only 99.89 percent local. Missing is enough locally-grown hops, which gives the beer its bitter taste.


To solve the problem (and just possibly – in my opinion – do a little product promotion) AC Golden is inviting customers to grow the hops and donate their harvest to the brewery. They announced this project on their Facebook page, and apparently drew a lot of response. The original deadline was November 15, but posts on Facebook indicate they were still accepting volunteer growers at mid-December.

The Post article explains that the brewer expects this program to yield only a small fraction of the 6,000 pelletized hops it expects to need in 2011. Colorado Native presently obtains 86 percent of its hops from Colorado, mostly commercial growers on the Western Slope. The rest comes mostly from Washington, Oregon, and Idaho.

Last summer I saw several rows of hops growing at CSU's Horticultural Research Center. They were part of the Specialty Crops Program shown to those attending the annual Turf and Horticulture Field Day. The Organic Hops Research project is testing twenty varieties of hops for their winter hardiness. There is also a study concerning hops plant disease.

I learned a little about the hops plant (Humulus lupulus) after I purchased one in a 3-inch pot several years ago. It is an easy vine to grow. It is quite hardy, but dies back to its rhizome root each year. Once mine was established growing on a yard fence, I gave it little extra water and no special care. Even so, I found it aggressive, its vines attaching themselves to nearby plants and its suckering roots invading adjacent plant beds. The flowers, which provide the beer flavoring, are a delightful surprise. They are described as cone-like spikes. Mine were up to two inches long, consisting of overlapping scales attached in whorls to a central core stem. There are some species of ornamental oregano bearing a similarly shaped flower. The scales are light green to yellow, fading and drying to a pale straw color. They are an interesting addition to floral arrangements, both fresh and dried. The standard leaf color is green, but a golden-leafed variety is considered more ornamental.

Why did I want to grow hops? Some years ago, when I had been asked to judge herbs at the Golden Garden Show, I was startled to find the show handbook listed a class for hops. I had never categorized this plant alongside thyme, rosemary, oregano, and the like. Then I realized that I was, after all, in Golden. There were no entries in this class, fortunately, as I wouldn't have known what to look for.

Later, when I came upon a plant at the Denver Botanic Gardens plant sale, I decided I should get to know it. Since that time, several local garden writers have mentioned it, particularly the golden-leaf version. They also cautioned that it's not the vine for every location.

Amazing Ivy by Gardener Dave

Boston Ivy



Are you an “Ivy Fan”? I am – up to a point. I use English Ivy (Hedera helix) as a groundcover for shade and semi-shade, and Boston Ivy (Parthenocissus tricuspidata) as a wall climber/cover in sunnier areas. Ivies can be used to “soften” a bare wall behind other plantings and provide added cooling and humidity in our dry climate. They can help to alleviate scorching and discourage spider mite infestations in sunny walled areas.

Part of my fascination with ivy is its ability to cover large expanses of ground, walls or fences quite quickly. I also like the evergreen (depending on our winter) qualities of English Ivy, and I like the fall reddening of Boston Ivy. I am also fascinated with the clever means by which these ivies climb walls and other vertical surfaces.

There are many other “ivies” and climbing plants that use different means of attachment, such as tendrils which wind around any supporting structure (and itself) in order to reach and grow upwards. I am only detailing here the ivies with which I have had personal experience. I also have some Virginia Creeper (Parthenocissus quinquefolia) – also sold as Engleman’s Ivy – coming into my yard from a neighbor’s. It does turn red in the fall, and it is very hardy, but it can be extremely invasive, and it is susceptible to powdery mildew which can spoil the fall color. Of the three types, English Ivy is the only one that is “evergreen” here (* See “Cautions” below).

In 1865, Darwin wrote about ivy at length in his book The Movements and Habits of Climbing Plants. The following are some of my own observations: My English Ivy has little “rootlets” that grow sideways from the main stems and take advantage of any little spaces on brick or stone walls, fence slats (or almost anything) to wedge itself in. The “rootlets” also adhere to surfaces very tenaciously. My Boston Ivy has little “feet” or “hands” growing from the main stems (please excuse my not using botanic terms for these appendages). Each “foot” has several little separate sticky pads that can seemingly attach to ANY surface with an extremely strong glue-like bond. They even attach to undersurfaces such as eaves and patio ceilings!


English Ivy


Geckos are famed for their ability to walk on walls, thanks to nanoscopic hairs on their feet called “setae”. http//www.newscientist.com/article/dn14902-geckogrip-material-aims-to-be-the-end-of-glue.html Ivy uses another nano-scale trick to defy gravity. Several articles I have read lately describe an exuded form of “nano-sized [cementing] globules” that allow ivy to cling tightly to surfaces. Researchers at the University of Tennessee in Knoxville have studied the process in depth, and say their tests reveal something like 19 different primary compounds in the ivy bonding process. I promise I won’t go into the chemical analysis of their research, but they report that millions or even billions of weak adhesion or hydrogen bonds (not bombs!) that the ivies produce, add up to make a very strong adhesion to climbing surfaces.

Researchers are also working on ways to counteract these forces with the goal of making paints that can protect surfaces from ivy damage. Also, researchers at University College Dublin in Ireland think that “…studying plants like ivy could uncover entirely novel nano-materials.” Perhaps new “miracle” adhesives?

Cautions: My ivies are not parasitic; they do not obtain nourishment from the trees, etc. that they climb on. But they will take advantage of any surface they can get their little “rootlets” into, “sticky pads” onto, or “tendrils” around. My ivies climb my brick house walls and fences and trees in my yard. They can also creep into windows and between (fairly tight) window panes. It looks “quaint” on a house wall and adds green interest to the overall landscape, but if you want to remove it, it can pose some problems. In our dry climate, the problem takes the form of leftover adhesions when you pull it off. A paint scraper or similar tool can help remove them, but they will never come off 100% unless the surface is vigorously sanded. Also, (*) English Ivy may winterburn in more-exposed areas, losing attractiveness and requiring some trimming back in Spring.

By way of interest – in moist climates, large overgrowths of ivy can bring down weakened tree branches, and its long-term decay against brick or stone walls can form humic acid which is capable of dissolving carbonate stone and some mortars. I seem to remember reading where some ivies are considered noxious weeds in moist climates, but in our area this should not be a problem with the three types I have mentioned.

Virginia Creeper

So – as I said earlier – I am an “Ivy Fan” up to a point. If you are willing to cut them back when you need to, they can be a nice green addition to your landscape. Don’t let them become too invasive, especially the Virginia Creeper or Engleman’s varieties. I have learned my lesson. Use them with this in mind and you will be happy with them. They are interesting, useful and decorative plants.

Cheers,
Gardener Dave